WO2014036701A1 - Tool for measuring pressure and speed of rotational flow field - Google Patents
Tool for measuring pressure and speed of rotational flow field Download PDFInfo
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- WO2014036701A1 WO2014036701A1 PCT/CN2012/081031 CN2012081031W WO2014036701A1 WO 2014036701 A1 WO2014036701 A1 WO 2014036701A1 CN 2012081031 W CN2012081031 W CN 2012081031W WO 2014036701 A1 WO2014036701 A1 WO 2014036701A1
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- probe
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- hot wire
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
- G01F1/34—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by measuring pressure or differential pressure
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/10—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables
Definitions
- the invention relates to the field of measurement of fluids. Specifically, a device for measuring the pressure and three-dimensional flow velocity of a swirl field using a seven-hole pressure probe and a one-dimensional hot wire probe in a swirling flow field. Background technique
- the cyclone field is a common phenomenon in engineering, and the distribution of large-scale vortices in the flow field is the main feature.
- the flow field at the downwind position of the building, the wing tip vortex field of the wing, the flow field around the rotor of the turbine engine, etc. and are usually turbulent fields.
- Research on such physical phenomena must accurately measure the pressure of the fluid flow and the three-dimensional transient velocity. From the measurement point of view, during the measurement of the swirl field, the velocity change rate of the two adjacent measurement points is large, which is a measurement of the large flow angle.
- Hot-wire anemometer is another commonly used flow velocity measurement tool.
- the principle is to use the fluid to flow through the hot wire to cause heat loss in the hot wire, resulting in a change in resistance.
- it has the characteristics of fast response and high accuracy, so it is often used for transient measurement of flow field, which is very suitable for analysis of turbulence characteristics of flow field.
- the measurement of three-dimensional flow velocity requires a three-dimensional hot wire, that is, a probe made of three hot wires.
- it is necessary to reduce the spatial scale as much as possible which is not only high in manufacturing cost but also difficult.
- the hot wire is easily broken, resulting in measurement failure.
- the hot wire anemometer When measuring the large flow angle with a three-dimensional hot wire anemometer, it is necessary to calibrate the state of the hot wire at all measurement angles. For example, it takes about 8 hours to calibrate a three-dimensional hotline with a flow field angle of -50° to +50°' and an interval of 5°. This can cause the electronic instrument to drift and distort the calibration results. Despite this, the hot wire anemometer is still the most effective flow measurement tool, especially the one-dimensional hot wire, which is widely used due to its simple structure and low production cost.
- Porous Pressure Probes including three, four, five, seven holes
- the basic principle for the measurement of three-dimensional velocity vectors is that the pressure difference measured from the different holes can determine the magnitude and direction of the fluid velocity.
- the fluid flow direction is a large flow angle with respect to the pressure probe fixed in the direction of placement.
- the fluid is exploring Flow separation occurs on the head, causing the fluid to not completely adhere to the probe surface.
- the pressure hole does not accurately obtain the local pressure value, and the measurement fails. This is often the case with three- and five-hole probes.
- the seven-hole pressure probe has a high application value and is more reliable when measuring large flow angles.
- the invention utilizes the respective advantages of the seven-hole pressure probe and the one-dimensional hot wire anemometer to design a measuring tool for the fluid flow of the swirl field, which combines the seven-hole pressure probe and the one-dimensional hot wire to measure the three-dimensional flow of the swirl field fluid. Transient flow, the device and operating process involved in pressure, velocity (including average velocity, instantaneous velocity) at high flow angles.
- the tool for measuring the pressure and velocity of a swirl field proposed by the present invention comprises a seven-hole pressure probe (1), a one-dimensional hot wire anemometer probe (2), a bracket system (2) having two rotational degrees of freedom, and a Three-degree-of-freedom translation mechanism (4), seven pressure sensors (5), pressure tube (6), room temperature bridge (7), wire (8), data acquisition management system (9), and control computer (10) component.
- Figure 1 is a layout diagram of a tool for measuring the pressure and velocity of a swirl field, showing the connection relationship of the above components. The figure indicates:
- the seven-hole pressure probe (1) and the hot wire anemometer probe (2) are positioned on a two-rotation degree support system (3); the two-degree-of-freedom support system (3) is fixed in a three-degree-of-freedom flat On the moving mechanism (4);
- the seven-hole pressure probe (1) is connected to seven pressure sensors (5) through a pressure tube (6), and then connected to the data acquisition system (9) and the control computer (10);
- the one-dimensional hot wire anemometer probe (2) is connected to the room temperature bridge (7) via the wire (8), and then connected to the data acquisition system (9) and the control computer (10).
- the seven-hole pressure probe (1) has a long cylindrical shape and has a truncated cone shape at its measuring end.
- Figure 2 is an external view and a top view of the measuring end of a seven-hole pressure probe.
- the top view is a view of the measuring end along the cylindrical axis of the seven-hole pressure probe.
- the seven-hole pressure probe has a central hole (11) with six additional peripheral holes (12) spaced 120° apart along its circumference.
- the center hole is also called a dynamic pressure hole; the six peripheral holes are also called static pressure holes, and the center hole (dynamic pressure hole) and the peripheral hole (static pressure hole) are pressure holes.
- the top view of Figure 2 illustrates the seven-hole unique partitioning strategy for a seven-hole pressure probe, as shown in Figure 3.
- the number on the center hole is 7 and the number of the peripheral holes is from 1 to 6.
- the seven wells are divided into six zones, each zone having four holes: holes 7-4-3-5; holes 7-3-2-4; holes 7-2-1-3; holes 7-1-2 - 6; Hole 7- 6- 1-5; Hole 7- 5- 4- 6.
- the above six areas are represented by area codes using 1 to 6. The measurement is effective as long as there is fluid adhesion in either zone.
- the angle between the flow direction and the direction of the fixedly placed seven-hole pressure probe (1) is large, even if the fluid is likely to be at the end of (1)
- the flow separation phenomenon occurs, the fluid does not completely adhere to the end surface, but there must be fluid attached to any of the six zones.
- the pressure values of the four pressure holes in the zone can obtain the three-dimensional velocity of the local fluid. And stress.
- the seven-hole pressure probe (1) can measure large angle flows.
- the seven-hole pressure probe ⁇ ) requires calibration before measurement.
- the one-dimensional hot wire anemometer probe (2) has the shape of an elongated cylinder.
- Figure 4 is an external view of the measuring end of the one-dimensional hot wire anemometer probe.
- a hot wire (13) is welded to the top of the hot wire holder (14), the hot wire holder is an electrical conductor, and the root is connected to the wire (8).
- the wire (8) is placed in a wire sleeve (15) that is in the form of a slender cylinder.
- the other end of the wire is connected to a normal temperature bridge (7).
- the fluid flows through the superheated wire (13), causing it to have a certain heat dissipation, resulting in a change in its resistance, and the output voltage value of the normal temperature bridge (7) changes.
- the relationship between the speed of the fluid and the output of the room temperature bridge (7) requires calibration.
- Figure 5 is a definition of two rotational degrees of freedom produced by a two-rotation degree support system (3), which means that the swing angles "° ( 16 ) and pitch angles ( 17 ) are generated in a Cartesian coordinate system. Turn. The angle of rotation of the two rotational degrees of freedom should cover the flow angle in the flow field.
- y, z are the three-dimensional directions of the Cartesian coordinate system.
- Figure 6 is a schematic view of the structure of a stent system having two rotational degrees of freedom.
- the figure shows the principle of the two degrees of freedom of the swing angles "° (16) and pitch angle (17).
- the system includes a probe positioning clip (18), a worm gear (19), a worm
- stepper motor No. 1 (20), stepper motor No. 1 (21), bracket (22), drive shaft (23), thrust bearing (24), stepper motor No. 2 (25) and other components.
- the connection relationship of each component is as shown in the figure.
- Figure 6 also shows that the two-degree-of-freedom bracket system (3) is attached to a three-degree-of-freedom translation mechanism (4).
- the three-degree-of-freedom translation mechanism refers to the motion in the three-dimensional plane direction in the Cartesian coordinate system, which is controlled by three stepping motors.
- the above two rotational degrees of freedom and three translational degrees of freedom constitute a total of five spatial degrees of freedom.
- Figure 7 shows the formation of a relationship between five spatial degrees of freedom.
- the figure shows: the translation (26) along the X-direction, the translation (27) in the y_ direction, and the translation (28) in the z_ direction, which can be used with two rotational degrees of freedom (3) Moving to any spatial point on the x_y, y_z, x_z plane, the swing angle "° (16) and pitch angle (17) shown in Figure 5 can be generated locally by a bracket system (3) with two degrees of rotational freedom. ) The rotation.
- the flow of the tool for measuring the pressure and velocity of the swirl field proposed by the present invention consists in: obtaining the flow direction of the measuring point with a seven-hole pressure probe, and then measuring the transient velocity in the flow direction at the same measuring point with a one-dimensional hot wire probe.
- Figure 8 is a flow chart of the process of using the tool. The figure shows that the tool usage process is divided into four steps. Specifically - the first step is the calibration of a seven-hole pressure probe;
- the second step is the calibration of the one-dimensional hot wire anemometer
- the third step is to obtain the flow angle of the measuring point with a seven-hole pressure probe
- the fourth step is to replace the seven-hole pressure probe with a one-dimensional hot wire probe for transient velocity measurements along known flow angles.
- Figure 1 is a layout of a tool for measuring the pressure and velocity of a swirl field.
- Figure 2 is an external view and a top view of the measuring end of the seven-hole pressure probe. In the figure, 11 center holes, 12 peripheral holes.
- Figure 3 shows the partitioning strategy for seven holes in a seven-hole pressure probe.
- Figure 4 is an external view of the measuring end of the one-dimensional hot wire anemometer probe.
- 13 hot wire 14 hot wire support, 15 wire sleeve.
- Figure 5 is a definition of two rotational degrees of freedom.
- Figure 6 is a schematic view of the structure of a stent system having two rotational degrees of freedom.
- Figure 7 is the formation of the relationship between the five spatial degrees of freedom.
- Figure 8 is a flow chart of the process of using the tool to measure the pressure and velocity of the swirl field.
- Figure 9 (a) and Figure 9 (b) are measurement schemes of the flow field of the three-dimensional wing wake.
- 30 wind tunnel air flow direction 31 three-dimensional wing, 29 wind tunnel, one seven-hole pressure probe, 2-dimensional hot wire anemometer probe, three bracket system with two rotational degrees of freedom, 4 three degrees of freedom translation Mechanism, 6 pressure tubes, 8 wires, 32 holes on the wall of the wind tunnel, 5 seven pressure sensors, 7 room temperature bridges, 33 signal amplifiers, 9 data acquisition management system, 10 control computers, 34 control lines.
- FIG. 9 (a), (b) is a measurement scheme of the flow field of the three-dimensional wing wake, showing the connection relationship between the seven-hole pressure probe (1) and the one-dimensional hot wire probe (2), and other components.
- the measuring device proposed by the present invention is placed in the wind tunnel (29) as a whole, and is placed in the three-dimensional wing (31) along the flow direction (30) of the airflow generated in the wind tunnel. Downstream.
- the static pressure ⁇ of the wind tunnel can be obtained from the static pressure hole on the wall surface, and the total pressure is determined by the state of the wind tunnel entrance.
- the wind tunnel produces a horizontal one-dimensional flow, and the flow velocity can be adjusted from subsonic to supersonic.
- the outline of the end of the seven-hole pressure probe in the shape of a slender cylindrical rod is the same as that of Fig. 2.
- the cone has a cone of thirty degrees and the cone volume is smaller than a sphere with a diameter of 3.5 mm.
- Each pressure hole has a diameter of 1.3 mm.
- the elongated cylinder has an outer diameter of 5 mm.
- the material is made of stainless steel.
- Figure 9 (a) shows the pressure tube (6) attached to the tail of the seven-hole pressure probe (1), here seven flexible thin tubes, protruding from the small hole (32) of the wall surface of the wind tunnel and seven pressure sensors ( 5) Connect, then connect the signal amplifier (33) and the data acquisition system (9).
- FIG. 9(b) shows the appearance of the one-dimensional hot wire probe as in Figure 4.
- the hot wire (13) is made of Nickel chromium and has a diameter of 5 ⁇ m.
- Hot wire bracket (14) Extends the long cylinder 3 wire (8) extends from the small hole (32) of the wind tunnel wall to the room temperature bridge (7), signal amplifier (33) and data acquisition system (9
- the data acquisition system (9) is connected to the control computer (10) and the two-rotation degree support system (3) and the three-degree-of-freedom translation mechanism (4) are adjusted via the control line (34).
- the first step is the calibration of the seven-hole pressure probe. Adjusting the three-degree-degree translation mechanism and the two-degree-of-freedom bracket system in the wind tunnel, positioning the seven-hole pressure probe in the center of the wind tunnel, and making the axial direction of the cylindrical shape of the seven-hole pressure probe The directions are the same, that is, the swing angle "° and the pitch angle are equal to zero.
- the calibrated flow angle is from -50° to 50° with an interval of 5° and a total of approximately 400 angles to be calibrated.
- the seven pressure values obtained from the seven pressure sensors connected to the seven-hole pressure probe are calculated to obtain fourteen pressure coefficients. They are that the radial pressure coefficient C and the tangential pressure coefficient are expressed as
- the fluid is completely attached to the probe, and the radial pressure coefficient and tangential pressure coefficient of the center hole (hole 7) can be obtained by the following formula.
- the calibration of the flow angle is independent of the incoming flow rate, and no other speed conditions are considered. If it takes 20 seconds for each calibration angle, a total of 400 angle calibrations are required for a total of 2.2 hours. After the calibration is completed, a calibration data list is formed, in which each calibration angle forms a one-to-one correspondence with 14 pressure coefficients.
- the second step of the measurement is to calibrate the one-dimensional hot wire probe in the wind tunnel. This process is a speed calibration and the calibration method is well known. At the time of calibration, the probe with a thin rod shape is placed in the direction of flow. This process is quick and easy. According to the calibration of 20 speed conditions, each working condition takes 20 seconds, and it takes about 7 minutes in total. The calibration process, which measures the first and second steps, does not exceed 3 hours in total.
- the measuring end of the seven-hole pressure probe can be reached at each measurement point in space.
- the pressure values of the seven pressure holes were obtained at each measurement point.
- the spatial position, flow angle and pressure coefficient of the measuring points are recorded as files by the data analysis and processing unit in the control computer of Fig. 1.
- the fourth step in the measurement is to measure the transient velocity with a one-dimensional hot wire probe.
- Through the control computer (10) at each measurement point, follow the recorded data about the spatial position and flow angle of the measurement point. Adjust the two-degree-of-freedom bracket system (3) and the three-degree-of-freedom translation mechanism (4) to reposition the one-dimensional hot wire probe (2) until it flows along the measurement point, known (" fl ,yT".
- the three-dimensional flow measurement of the flow field is processed into a local one-dimensional flow measurement.
- each measurement point of the flow field is measured twice, the flow direction of the flow field is obtained by the first pressure probe for the first time, and the transient speed of the flow field is obtained by the second time using the one-dimensional hot line probe.
- the above measuring device and flow are suitable for the swirl field, that is, the measurement of the flow field at a large flow angle, replacing the three-dimensional hot wire anemometer which is usually required in this situation.
- the total measurement time is not significantly increased because the measurement of the seven-hole pressure probe and the one-dimensional hot wire is much less than that of the three-dimensional hot wire.
- each calibration angle takes 20 seconds, 20 speed conditions.
- 20 seconds x 20 x 400 44 hours.
- the use of the invention makes the measurement process simple and fast. As mentioned above, the calibration time is less than 3 hours, saving 90% of the time, greatly shortening and simplifying the hot line calibration time and process, and reducing the length of the measuring instrument. The error caused by overheating makes the measurement result more reliable.
- the production cost of a seven-hole pressure probe is about 10% of that of a one-dimensional hot-wire probe, while the cost of a one-dimensional hot-wire probe is about 1% of that of a three-dimensional hot-wire probe.
- a three-dimensional transient measurement using a seven-hole pressure probe and a one-dimensional hot wire anemometer typically uses a three-dimensional hot wire anemometer method that reduces manufacturing costs by more than 95%.
- Thrust bearing Stepper motor No. 2 X-direction translation y_direction translation Z-direction translation Wind tunnel
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Abstract
The present invention relates to the field of fluid measuring, in particular to a device for measuring pressure and three-dimensional flow speed of rotational flow field by a seven-hole pressure probe and a one-dimensional hot-wire probe in a rotational flow field. The device comprises: a seven-hole pressure probe (1), a one-dimensional hot wire wind velocity probe (2), a support system with two rotary degrees of freedom (3), a translation mechanism with three degrees of freedom (4), seven pressure sensors (5), a pressure pipe (6), a normal bridge (7), a lead wire (8), a data acquisition management system (9) and a control computer (10) etc.
Description
测量旋流场的压力和速度的工具 Tool for measuring the pressure and velocity of a swirl field
技术领域 Technical field
本发明涉及流体的测量领域。 具体是在旋流场中利用七孔压力探头和一维热线探头来测 量旋流场的压力和三维流速的装置。 背景技术 The invention relates to the field of measurement of fluids. Specifically, a device for measuring the pressure and three-dimensional flow velocity of a swirl field using a seven-hole pressure probe and a one-dimensional hot wire probe in a swirling flow field. Background technique
旋流场是工程中常见的现象, 以流场中分布大尺度旋涡为主要特征。 例如, 建筑物下风 位置的流场、 机翼的翼尖涡流场、 涡轮发动机转子周围的流场等等, 而且通常都是湍流场。 针对这类物理现象的研究必须精确测量流体流动的压力和三维瞬态速度。 从测量的角度讲, 旋流场的测量过程中, 两个邻近的测量点的速度方向变化率较大, 是大流动角度的测量。 The cyclone field is a common phenomenon in engineering, and the distribution of large-scale vortices in the flow field is the main feature. For example, the flow field at the downwind position of the building, the wing tip vortex field of the wing, the flow field around the rotor of the turbine engine, etc., and are usually turbulent fields. Research on such physical phenomena must accurately measure the pressure of the fluid flow and the three-dimensional transient velocity. From the measurement point of view, during the measurement of the swirl field, the velocity change rate of the two adjacent measurement points is large, which is a measurement of the large flow angle.
随着电子、 光学技术日益进步, 激光多普勒测速仪(LDA), 粒子成像测速技术(PIV)等 流体测量方法已经有了广泛的应用。 然而用上述流体测量仪器往往需要较大的制造和使用成 本, 而且都是应用在较小的测量区域内, 测量结果必须通过对信号的后处理技术才能获得。 多普勒测速和示踪粒子成像测速都需要示踪粒子, 示踪粒子相对流体流动的跟随性问题, 即 示踪粒子是否能够真实地反应流体的流动状态。 由于示踪粒子的密度和流体密度的差异, 导 致两者的转动惯量不同。 在旋流场中, 示踪粒子不能真实反映当地流体的运动轨迹。 这类测 量技术的可靠性在旋流场的测量中得不到保障。 With the advancement of electronic and optical technologies, fluid measurement methods such as laser Doppler velocimetry (LDA) and particle imaging velocimetry (PIV) have been widely used. However, the above fluid measuring instruments often require large manufacturing and use costs, and are applied in a small measuring area, and the measurement results must be obtained by post-processing techniques on the signals. Both Doppler velocity measurement and tracer particle imaging velocity require tracer particles to trace the follow-up of the particle relative to the fluid flow, ie, whether the tracer particle can truly reflect the flow state of the fluid. Due to the difference in density of the tracer particles and the density of the fluid, the moment of inertia of the two is different. In the cyclone field, the tracer particles do not truly reflect the trajectory of the local fluid. The reliability of this type of measurement technique is not guaranteed in the measurement of the cyclone field.
热线风速仪 (Hot-wire anemometer) 是另一类常用的流场速度测量工具, 其原理是利用 流体流经热线时, 使热线产生热量损失, 从而导致电阻的变化。 特别是具有响应快、 准确性 高的特点, 因而常被用于流场的瞬态测量, 非常适合对流场的湍流特性分析。 三维流动速度 的测量需要三维热线, 即三根热丝制成的探头, 为了减小呈细杆状的热线探头对流场的扰动, 需要尽量减小其空间尺度, 不仅制造成本高、 难度大, 而且在实际应用过程中, 热丝极易折 断, 致使测量失败。 三维热线风速仪测量大流动角度时, 需要对所有的测量角度下的热线的 状态进行标定。例如, 对于流场流动角度在 -50°到 +50°'、间隔为 5°的三维热线标定的时间约需 要 8个小时。 这会引起电子仪器发生飘移, 使得标定结果失真。 尽管如此, 热线风速仪仍是 最有效的流速测量工具, 特别是一维热线, 由于结构简单、 制作成本低而得到广泛应用。 Hot-wire anemometer is another commonly used flow velocity measurement tool. The principle is to use the fluid to flow through the hot wire to cause heat loss in the hot wire, resulting in a change in resistance. In particular, it has the characteristics of fast response and high accuracy, so it is often used for transient measurement of flow field, which is very suitable for analysis of turbulence characteristics of flow field. The measurement of three-dimensional flow velocity requires a three-dimensional hot wire, that is, a probe made of three hot wires. In order to reduce the disturbance of the flow field of the thin rod-shaped hot wire probe, it is necessary to reduce the spatial scale as much as possible, which is not only high in manufacturing cost but also difficult. Moreover, in the actual application process, the hot wire is easily broken, resulting in measurement failure. When measuring the large flow angle with a three-dimensional hot wire anemometer, it is necessary to calibrate the state of the hot wire at all measurement angles. For example, it takes about 8 hours to calibrate a three-dimensional hotline with a flow field angle of -50° to +50°' and an interval of 5°. This can cause the electronic instrument to drift and distort the calibration results. Despite this, the hot wire anemometer is still the most effective flow measurement tool, especially the one-dimensional hot wire, which is widely used due to its simple structure and low production cost.
很多场合, 特别是对于流体平均流动速度的测量, 多孔压力探头, 由于具有低成本, 加 工制造简单的特点, 仍然有广泛的应用。 多孔压力探头 (包括三、 四、 五、 七孔) 用于三维 速度矢量的测量的基本原理在于从不同孔中测量得的压力差可以判定流体速度大小和方向。 旋流场中, 相对于放置方向固定的压力探头, 流体流动方向是大流动角度。 此时, 流体在探
头上会产生流动分离现象, 致使流体不能完全地附着在探头表面, 压力孔则不能准确获得当 地的压力值, 测量失败。 三孔和五孔探头经常发生这样的情况。 相比之下, 七孔压力探头有 较高的应用价值, 在测量较大的流动角度时, 更加可靠。 In many occasions, especially for the measurement of the average flow velocity of a fluid, a porous pressure probe has a wide range of applications due to its low cost and simple manufacturing. Porous Pressure Probes (including three, four, five, seven holes) The basic principle for the measurement of three-dimensional velocity vectors is that the pressure difference measured from the different holes can determine the magnitude and direction of the fluid velocity. In the swirl field, the fluid flow direction is a large flow angle with respect to the pressure probe fixed in the direction of placement. At this point, the fluid is exploring Flow separation occurs on the head, causing the fluid to not completely adhere to the probe surface. The pressure hole does not accurately obtain the local pressure value, and the measurement fails. This is often the case with three- and five-hole probes. In contrast, the seven-hole pressure probe has a high application value and is more reliable when measuring large flow angles.
总之, 对于旋流场的压力和速度的测量需要开发一种精确、 可靠、 低成本的测量工具。 发明内容 In summary, the measurement of the pressure and velocity of the cyclone field requires the development of an accurate, reliable, and low-cost measurement tool. Summary of the invention
本发明利用七孔压力探头和一维热线风速仪的各自的优势, 设计一套用于旋流场流体流 动的测量工具, 既是将七孔压力探头和一维热线结合起来测量旋流场流体的三维瞬态流动, 即在大流动角度时的压力、 速度 (包括平均速度、 瞬时速度) 所涉及的装置和操作过程。 The invention utilizes the respective advantages of the seven-hole pressure probe and the one-dimensional hot wire anemometer to design a measuring tool for the fluid flow of the swirl field, which combines the seven-hole pressure probe and the one-dimensional hot wire to measure the three-dimensional flow of the swirl field fluid. Transient flow, the device and operating process involved in pressure, velocity (including average velocity, instantaneous velocity) at high flow angles.
本发明提出的测量旋流场的压力和速度的工具包括一个七孔压力探头 (1 )、 一个一维热 线风速仪探头 (2)、 一个有两个转动自由度的支架*** (3 )、 一个三自由度平动机构 (4)、 七个压力传感器 (5)、 压力管 (6)、 常温电桥 (7)、 导线 (8)、 数据采集管理*** (9)及控 制计算机 (10) 等部件。 图 1是测量旋流场的压力和速度的工具的布局图, 表明了上述部件 的连接关系。 图中标明: The tool for measuring the pressure and velocity of a swirl field proposed by the present invention comprises a seven-hole pressure probe (1), a one-dimensional hot wire anemometer probe (2), a bracket system (2) having two rotational degrees of freedom, and a Three-degree-of-freedom translation mechanism (4), seven pressure sensors (5), pressure tube (6), room temperature bridge (7), wire (8), data acquisition management system (9), and control computer (10) component. Figure 1 is a layout diagram of a tool for measuring the pressure and velocity of a swirl field, showing the connection relationship of the above components. The figure indicates:
七孔压力探头(1 )和热线风速仪探头(2)定位在有两个转动自由度的支架***(3)上; 有两个转动自由度的支架*** (3) 固定在一个三自由度平动机构 (4) 上; The seven-hole pressure probe (1) and the hot wire anemometer probe (2) are positioned on a two-rotation degree support system (3); the two-degree-of-freedom support system (3) is fixed in a three-degree-of-freedom flat On the moving mechanism (4);
七孔压力探头 (1 ) 通过压力管 (6 ) 连接到七个压力传感器 (5), 再连接到数据采集系 统 (9) 、 控制计算机 (10) ; The seven-hole pressure probe (1) is connected to seven pressure sensors (5) through a pressure tube (6), and then connected to the data acquisition system (9) and the control computer (10);
一维热线风速仪探头 (2 ) 通过导线 (8) 连接到常温电桥 (7), 再连接到数据采集*** (9) 、 控制计算机 (10) 。 七孔压力探头(1 ) 的外形呈长圆柱体形状, 在其测量端端部呈圆锥台形状。 图 2是七孔 压力探头的测量端的外观图和顶视图。 顶视图是沿着七孔压力探头的圆柱形的轴线观看测量 端的视图。 七孔压力探头有一个中心孔 (11 ), 沿着其圆周方向均勾地分布着另外六个间隔 120°的周边孔 (12)。 中心孔也称作动压孔; 六个周边孔也称作静压孔, 中心孔 (动压孔)和 周边孔 (静压孔) 都是压力孔。 The one-dimensional hot wire anemometer probe (2) is connected to the room temperature bridge (7) via the wire (8), and then connected to the data acquisition system (9) and the control computer (10). The seven-hole pressure probe (1) has a long cylindrical shape and has a truncated cone shape at its measuring end. Figure 2 is an external view and a top view of the measuring end of a seven-hole pressure probe. The top view is a view of the measuring end along the cylindrical axis of the seven-hole pressure probe. The seven-hole pressure probe has a central hole (11) with six additional peripheral holes (12) spaced 120° apart along its circumference. The center hole is also called a dynamic pressure hole; the six peripheral holes are also called static pressure holes, and the center hole (dynamic pressure hole) and the peripheral hole (static pressure hole) are pressure holes.
利用图 2的顶视图可以说明七孔压力探头的七个孔特有的分区策略, 如图 3所示。 中心 孔上的标号为 7,周边孔的标号从 1到 6。 将七个孔分成六个区,每个区有四个孔:孔 7-4-3-5; 孔 7-3-2-4; 孔 7-2-1-3; 孔 7- 1-2- 6; 孔 7- 6- 1-5; 孔 7- 5- 4- 6。 以上六个区使用 1至 6表 示为区号。 只要在任一个区内有流体的附着, 测量即为有效。 针对旋流场的流动特点, 流动 方向和固定放置的七孔压力探头 (1 ) 的方向之间的角度较大, 即使流体有可能在 (1 ) 的端
部发生流动分离现象, 流体没有完全附着在其端部表面, 但是必然有流体附着在六个区内的 任一区内, 该区的四个压力孔的压力值即可获得当地流体的三维速度和压力。 因而, 七孔压 力探头 (1 ) 可以测量大角度的流动。 七孔压力探头 α ) 在测量使用之前需要标定。 The top view of Figure 2 illustrates the seven-hole unique partitioning strategy for a seven-hole pressure probe, as shown in Figure 3. The number on the center hole is 7 and the number of the peripheral holes is from 1 to 6. The seven wells are divided into six zones, each zone having four holes: holes 7-4-3-5; holes 7-3-2-4; holes 7-2-1-3; holes 7-1-2 - 6; Hole 7- 6- 1-5; Hole 7- 5- 4- 6. The above six areas are represented by area codes using 1 to 6. The measurement is effective as long as there is fluid adhesion in either zone. For the flow characteristics of the swirl field, the angle between the flow direction and the direction of the fixedly placed seven-hole pressure probe (1) is large, even if the fluid is likely to be at the end of (1) The flow separation phenomenon occurs, the fluid does not completely adhere to the end surface, but there must be fluid attached to any of the six zones. The pressure values of the four pressure holes in the zone can obtain the three-dimensional velocity of the local fluid. And stress. Thus, the seven-hole pressure probe (1) can measure large angle flows. The seven-hole pressure probe α) requires calibration before measurement.
一维热线风速仪探头(2)外形是呈细长圆柱体的形状。 图 4是一维热线风速仪探头的测 量端的外观图。 一根热丝 (13) 焊接在热丝支架 (14) 顶部, 热丝支架为导电体, 根部连接 导线 (8)。 导线 (8)置于外形是呈细长圆柱体的导线套筒 (15) 内。 导线另一端连接常温电 桥(7)。 流体流过热丝 (13), 造成其产生一定的热耗散, 导致其电阻的变化, 常温电桥 (7) 输出电压值产生变化。 流体的速度和常温电桥 (7) 的输出之间的关系需要标定。 The one-dimensional hot wire anemometer probe (2) has the shape of an elongated cylinder. Figure 4 is an external view of the measuring end of the one-dimensional hot wire anemometer probe. A hot wire (13) is welded to the top of the hot wire holder (14), the hot wire holder is an electrical conductor, and the root is connected to the wire (8). The wire (8) is placed in a wire sleeve (15) that is in the form of a slender cylinder. The other end of the wire is connected to a normal temperature bridge (7). The fluid flows through the superheated wire (13), causing it to have a certain heat dissipation, resulting in a change in its resistance, and the output voltage value of the normal temperature bridge (7) changes. The relationship between the speed of the fluid and the output of the room temperature bridge (7) requires calibration.
图 5是有两个转动自由度的支架***(3)产生的两个转动自由度的定义, 即是指在笛卡 尔坐标系下产生摆动角度《° ( 16 ) 和仰俯角度 ( 17) 的转动。 两个转动自由度转动的角 度应该覆盖流场中的流动角度。 图中 , y, z是笛卡尔坐标系的三维方向。 Figure 5 is a definition of two rotational degrees of freedom produced by a two-rotation degree support system (3), which means that the swing angles "° ( 16 ) and pitch angles ( 17 ) are generated in a Cartesian coordinate system. Turn. The angle of rotation of the two rotational degrees of freedom should cover the flow angle in the flow field. In the figure, y, z are the three-dimensional directions of the Cartesian coordinate system.
图 6是有两个旋转自由度的支架***的结构示意图。 图中表示了摆动角度《° ( 16)和仰 俯角度 ( 17)两个自由度产生的原理。 该***包括探头定位夹子 (18)、 蜗轮 (19)、 蜗杆 Figure 6 is a schematic view of the structure of a stent system having two rotational degrees of freedom. The figure shows the principle of the two degrees of freedom of the swing angles "° (16) and pitch angle (17). The system includes a probe positioning clip (18), a worm gear (19), a worm
( 20)、 步进电机 1号 (21 )、 支架(22)、 传动轴 (23)、 止推轴承(24)、 步进电机 2号 (25) 等部件。 各个部件的连接关系如图中所示。 (20), stepper motor No. 1 (21), bracket (22), drive shaft (23), thrust bearing (24), stepper motor No. 2 (25) and other components. The connection relationship of each component is as shown in the figure.
图 6也表示了有两个转动自由度的支架***(3) 固定在一个三自由度平动机构(4)上。 三自由度平动机构是指笛卡尔坐标系下的三维平面方向上的运动,分别由三台步进电机控制。 上述两个转动自由度和三个平动自由度共构成五个空间自由度。 图 7表示了五个空间自由度 之间的关系的形成。 图中表示: 沿着 X-方向的平动 (26)、 y_方向的平动 (27)、 z_方向的平 动 (28) ,可以将有两个转动自由度的支架*** (3) 移动到 x_y、 y_z、 x_z平面上的任意空 间点, 在当地可以由有两个转动自由度的支架*** (3)产生如图 5所示的摆动角度《° ( 16) 和仰俯角度 ( 17) 的转动。 本发明提出的测量旋流场的压力和速度的工具的使用流程在于: 用七孔压力探头获得测 量点的流动方向, 然后用一维热线探头在同一个测量点沿流动方向测量瞬态速度。 图 8是该 工具的使用过程的流程图。 图中表示, 该工具使用过程具体分为四步。 具体是- 第一步是七孔压力探头的标定; Figure 6 also shows that the two-degree-of-freedom bracket system (3) is attached to a three-degree-of-freedom translation mechanism (4). The three-degree-of-freedom translation mechanism refers to the motion in the three-dimensional plane direction in the Cartesian coordinate system, which is controlled by three stepping motors. The above two rotational degrees of freedom and three translational degrees of freedom constitute a total of five spatial degrees of freedom. Figure 7 shows the formation of a relationship between five spatial degrees of freedom. The figure shows: the translation (26) along the X-direction, the translation (27) in the y_ direction, and the translation (28) in the z_ direction, which can be used with two rotational degrees of freedom (3) Moving to any spatial point on the x_y, y_z, x_z plane, the swing angle "° (16) and pitch angle (17) shown in Figure 5 can be generated locally by a bracket system (3) with two degrees of rotational freedom. ) The rotation. The flow of the tool for measuring the pressure and velocity of the swirl field proposed by the present invention consists in: obtaining the flow direction of the measuring point with a seven-hole pressure probe, and then measuring the transient velocity in the flow direction at the same measuring point with a one-dimensional hot wire probe. Figure 8 is a flow chart of the process of using the tool. The figure shows that the tool usage process is divided into four steps. Specifically - the first step is the calibration of a seven-hole pressure probe;
第二步是一维热线风速仪的标定; The second step is the calibration of the one-dimensional hot wire anemometer;
第三步是用七孔压力探头获得测量点的流动角度; The third step is to obtain the flow angle of the measuring point with a seven-hole pressure probe;
第四步是用一维热线探头替换七孔压力探头, 沿着已知的流动角度进行瞬态速度测量。
附图说明 The fourth step is to replace the seven-hole pressure probe with a one-dimensional hot wire probe for transient velocity measurements along known flow angles. DRAWINGS
图 1是测量旋流场的压力和速度的工具的布局图。 图中, 1七孔压力探头、 2—维热线风速仪 探头、 3有两个转动自由度的支架***、 4三自由度平动机构、 5七个压力传感器、 6压 力管、 7常温电桥、 8导线、 9数据采集管理***、 10控制计算机。 Figure 1 is a layout of a tool for measuring the pressure and velocity of a swirl field. In the figure, 1 seven-hole pressure probe, 2-dimensional hot wire anemometer probe, 3 bracket system with two rotational degrees of freedom, 4 three-degree-of-freedom translation mechanism, 57 pressure sensors, 6 pressure tubes, 7 room temperature bridge , 8 wires, 9 data acquisition management system, 10 control computer.
图 2是七孔压力探头的测量端的外观图和顶视图。 图中, 11中心孔、 12周边孔。 Figure 2 is an external view and a top view of the measuring end of the seven-hole pressure probe. In the figure, 11 center holes, 12 peripheral holes.
图 3是七孔压力探头七个孔的分区策略。 Figure 3 shows the partitioning strategy for seven holes in a seven-hole pressure probe.
图 4是一维热线风速仪探头的测量端的外观图。 图中, 13热丝、 14热丝支架、 15导线套筒。 图 5是两个转动自由度的定义。 图中, 16摆动角度《 、 17仰俯角度 、 1七孔压力探头、 2 一维热线风速仪探头。 Figure 4 is an external view of the measuring end of the one-dimensional hot wire anemometer probe. In the figure, 13 hot wire, 14 hot wire support, 15 wire sleeve. Figure 5 is a definition of two rotational degrees of freedom. In the figure, 16 swing angles, 17 pitch angle, 1 seven-hole pressure probe, 2 one-dimensional hot wire anemometer probe.
图 6是有两个旋转自由度的支架***的结构示意图。 图中, 16摆动角度《°、 21步进电机 1 号、 24止推轴承、 22支架、 17仰俯角度 、 1七孔压力探头、 2—维热线风速仪探头、Figure 6 is a schematic view of the structure of a stent system having two rotational degrees of freedom. In the figure, 16 swing angles "°, 21 stepping motor No. 1, 24 thrust bearing, 22 bracket, 17 pitch angle, 1 seven-hole pressure probe, 2-wei hot wire anemometer probe,
19蜗轮、 18定位夹子、 20蜗杆、 23传动轴、 25步进电机 2号、 4三自由度平动机构。 图 7是五个空间自由度之间的关系的形成。 图中, 1七孔压力探头、 2—维热线风速仪探头、19 worm gear, 18 positioning clamp, 20 worm, 23 drive shaft, 25 stepping motor 2, 4 three degrees of freedom translation mechanism. Figure 7 is the formation of the relationship between the five spatial degrees of freedom. In the figure, a seven-hole pressure probe, 2-dimensional hot wire anemometer probe,
17仰俯角度 、 16摆动角度《°、 27 y_方向的平动、 28 z_方向的平动 26 χ-方向的平 动、 4三自由度平动机构、 3有两个转动自由度的支架***。 17 pitch angle, 16 swing angle "°, 27 y_ direction translation, 28 z_ direction translation 26 χ-direction translation, 4 three-degree-of-freedom translation mechanism, 3 with two rotational degrees of freedom Bracket system.
图 8是测量旋流场的压力和速度的工具的使用过程的流程图。 Figure 8 is a flow chart of the process of using the tool to measure the pressure and velocity of the swirl field.
图 9 (a)、 图 9 (b)是三维机翼尾流的流场的测量方案图。 图中, 30风洞气流流动方向、 31三 维机翼、 29风洞、 1七孔压力探头、 2—维热线风速仪探头、 3有两个转动自由度的支架 ***、 4三自由度平动机构、 6压力管、 8导线、 32风洞壁面上的小孔、 5七个压力传感 器、 7常温电桥、 33信号放大器、 9数据采集管理***、 10控制计算机、 34控制线。 Figure 9 (a) and Figure 9 (b) are measurement schemes of the flow field of the three-dimensional wing wake. In the figure, 30 wind tunnel air flow direction, 31 three-dimensional wing, 29 wind tunnel, one seven-hole pressure probe, 2-dimensional hot wire anemometer probe, three bracket system with two rotational degrees of freedom, 4 three degrees of freedom translation Mechanism, 6 pressure tubes, 8 wires, 32 holes on the wall of the wind tunnel, 5 seven pressure sensors, 7 room temperature bridges, 33 signal amplifiers, 9 data acquisition management system, 10 control computers, 34 control lines.
具体实施方式 detailed description
以下结合具体实施例子对本发明的结构和原理做进一步说明。 该实施例子是用本发明提 出的测量旋流场的压力和速度的工具在亚音速风洞中测量三维机翼尾流的三维瞬态流场。 众 所周知, 三维机翼尾流的流场是以翼尖涡结构为主要特征。 翼尖涡结构表现为流动的螺旋形 状并向下游传播, 是高度旋转的流场。 图 9 (a)、 (b)是三维机翼尾流的流场的测量方案图, 分别表示了七孔压力探头 (1 )和一维热线探头 (2), 与其他部件的连接关系。 该具体实施例 子使用的测量旋流场的压力和速度的工具的部件组成、 布局和连接关系与图 1所示相同, 这 里不再叙述。
如图 (a)、 (b)中所示, 本发明提出的测量装置整体放在风洞 (29) 中, 沿着风洞内产生 的气流流动方向 (30) 安置在三维机翼 (31) 的下游。 风洞的静压 ρ 可从壁面上的静压孔 获得, 总压 ^由风洞入口状态决定。 风洞产生水平一维来流, 流速可以从亚音速到超音速 进行调节, 不同的风速下, 风洞的静压 改变, 风洞的总压 ptoi不变。 呈细长圆柱体杆状的七孔压力探头端部外形图与图 2相同。圆锥呈三十度的锥形,锥形体 积小于直径为 3.5mm的球体。 每个压力孔的直径 1.3mm。 细长圆柱体外径为 5mm。材料为不锈 钢制成。 七孔压力探头 (1) 的七个孔的分区策略如图 3所示。 The structure and principle of the present invention will be further described below in conjunction with specific embodiments. This embodiment is based on the tool for measuring the pressure and velocity of a swirl field proposed by the present invention to measure a three-dimensional transient flow field of a three-dimensional wing wake in a subsonic wind tunnel. It is well known that the flow field of a three-dimensional wing wake is characterized by a wing tip vortex structure. The wing tip vortex structure appears as a spiral shape of the flow and propagates downstream, which is a highly rotating flow field. Figure 9 (a), (b) is a measurement scheme of the flow field of the three-dimensional wing wake, showing the connection relationship between the seven-hole pressure probe (1) and the one-dimensional hot wire probe (2), and other components. The component composition, layout, and connection relationship of the tool for measuring the pressure and velocity of the swirl field used in this embodiment are the same as those shown in Fig. 1, and will not be described here. As shown in (a) and (b), the measuring device proposed by the present invention is placed in the wind tunnel (29) as a whole, and is placed in the three-dimensional wing (31) along the flow direction (30) of the airflow generated in the wind tunnel. Downstream. The static pressure ρ of the wind tunnel can be obtained from the static pressure hole on the wall surface, and the total pressure is determined by the state of the wind tunnel entrance. The wind tunnel produces a horizontal one-dimensional flow, and the flow velocity can be adjusted from subsonic to supersonic. Under different wind speeds, the static pressure of the wind tunnel changes, and the total pressure p toi of the wind tunnel does not change. The outline of the end of the seven-hole pressure probe in the shape of a slender cylindrical rod is the same as that of Fig. 2. The cone has a cone of thirty degrees and the cone volume is smaller than a sphere with a diameter of 3.5 mm. Each pressure hole has a diameter of 1.3 mm. The elongated cylinder has an outer diameter of 5 mm. The material is made of stainless steel. The partitioning strategy for the seven holes of the seven-hole pressure probe (1) is shown in Figure 3.
图 9(a)表示七孔压力探头 (1) 的尾部连接有压力管 (6), 此处为七根柔性细管, 从风 洞壁面的小孔 (32)伸出与七个压力传感器 (5)相连, 再连接信号放大器(33)和数据采集 *** (9)。 Figure 9 (a) shows the pressure tube (6) attached to the tail of the seven-hole pressure probe (1), here seven flexible thin tubes, protruding from the small hole (32) of the wall surface of the wind tunnel and seven pressure sensors ( 5) Connect, then connect the signal amplifier (33) and the data acquisition system (9).
图 9(b)表示一维热线探头外形与图 4 相同。 热丝 (13) 材料为镍铬合金 (Nickel chromium), 直径为 5 μ m。 热丝支架 (14) 伸出长圆柱体 3 导线 (8) 从风洞壁面的小孔 (32) 伸出连接到常温电桥 (7)、 信号放大器 (33) 和数据采集*** (9 Figure 9(b) shows the appearance of the one-dimensional hot wire probe as in Figure 4. The hot wire (13) is made of Nickel chromium and has a diameter of 5 μm. Hot wire bracket (14) Extends the long cylinder 3 wire (8) extends from the small hole (32) of the wind tunnel wall to the room temperature bridge (7), signal amplifier (33) and data acquisition system (9
数据采集*** (9) 连接控制计算机 (10), 并通过控制线 (34) 调整有两个转动自由度 的支架*** (3) 和三自由度平动机构 (4)。 The data acquisition system (9) is connected to the control computer (10) and the two-rotation degree support system (3) and the three-degree-of-freedom translation mechanism (4) are adjusted via the control line (34).
按照图 8给出的该工具的使用过程的流程图, 第一步是七孔压力探头的标定。 在风洞中 调整三个自由度的平动机构和有两个转动自由度的支架***,定位七孔压力探头在风洞中心, 并使七孔压力探头的圆柱形外形的轴线方向与来流方向一致, 即摆动角度《°和仰俯角度 等于零。 标定的流动角度从 -50°到 50°, 间隔为 5°, 共约 400个需要标定的角度。 对于每个 用不同的 表示的、需要标定的角度, 需要从连接七孔压力探头的七个压力传感器获取 的七个压力值经过计算获得十四个压力系数。它们是,径向压力系数 C 和切向压力系数 分别表示为 According to the flow chart of the use of the tool given in Figure 8, the first step is the calibration of the seven-hole pressure probe. Adjusting the three-degree-degree translation mechanism and the two-degree-of-freedom bracket system in the wind tunnel, positioning the seven-hole pressure probe in the center of the wind tunnel, and making the axial direction of the cylindrical shape of the seven-hole pressure probe The directions are the same, that is, the swing angle "° and the pitch angle are equal to zero. The calibrated flow angle is from -50° to 50° with an interval of 5° and a total of approximately 400 angles to be calibrated. For each angle that needs to be calibrated with a different representation, the seven pressure values obtained from the seven pressure sensors connected to the seven-hole pressure probe are calculated to obtain fourteen pressure coefficients. They are that the radial pressure coefficient C and the tangential pressure coefficient are expressed as
Cpr, ^ ; (1)Cpr, ^ ; (1)
PP
Cpti = Pj「Pj2 , (2) '· 2 Cpti = Pj " Pj2 , (2) '· 2
式中变量的下标 表示孔的标号, 也是图 3中表示的分区策略的区号, i=l, 2, ...6.
如果 =7, 则 J7=^J2= 如果 则 J7=^J2=7, 当 等于其他, jl=i+l;j2=i-l。 针对小角度的流动方向 (流动角小于 30°) 的情况,流体完全附着在探头上, 中心孔 (孔 7 ) 的径向压力系数和切向压力系数可用下式求得, The subscript of the variable in the formula indicates the label of the hole, which is also the area code of the partitioning strategy shown in Fig. 3, i=l, 2, ... 6. If =7, then J7=^J2= If J7=^J2=7, when equal to the other, jl=i+l;j2=il. For small angle flow directions (flow angle less than 30°), the fluid is completely attached to the probe, and the radial pressure coefficient and tangential pressure coefficient of the center hole (hole 7) can be obtained by the following formula.
Cptb - Cptc Cptb - Cptc
Cpr7 = Cpta + - ( 3 ) Cpr 7 = Cpta + - ( 3 )
2 2
其中 among them
CptaCpta
从这个过程可以看出, 在求取压力系数的公式中没有与来流速度相关的风洞的总压 Ptot 和静压 值。 因而, 流动角度的标定与来流速度无关, 不用考虑其他速度工况。 如果在每 一个标定角度耗时 20秒, 全范围 400个角度标定共需 2. 2小时。标定结束后, 形成标定数据 列表, 其中每一个标定角度 都和 14个压力系数形成一一对应关系。 测量的第二步是在风洞中进行一维热线探头的标定。 这个过程是进行速度标定, 标定方 法是公知的。 标定时, 呈细杆状的探头沿来流方向放置。 这个过程快捷、 简单。 按照 20个速 度工况标定, 每个工况需 20秒, 总共需要约 7分钟。 标定过程, 即测量第一步和第二步, 总 共不超过 3小时。 It can be seen from this process that there is no total pressure Ptot and static pressure value of the wind tunnel associated with the incoming flow velocity in the formula for determining the pressure coefficient. Therefore, the calibration of the flow angle is independent of the incoming flow rate, and no other speed conditions are considered. If it takes 20 seconds for each calibration angle, a total of 400 angle calibrations are required for a total of 2.2 hours. After the calibration is completed, a calibration data list is formed, in which each calibration angle forms a one-to-one correspondence with 14 pressure coefficients. The second step of the measurement is to calibrate the one-dimensional hot wire probe in the wind tunnel. This process is a speed calibration and the calibration method is well known. At the time of calibration, the probe with a thin rod shape is placed in the direction of flow. This process is quick and easy. According to the calibration of 20 speed conditions, each working condition takes 20 seconds, and it takes about 7 minutes in total. The calibration process, which measures the first and second steps, does not exceed 3 hours in total.
测量的第三步是用七孔压力探头获得测量点的流动方向。 将七孔压力探头保持在标定时 的位置, 即《 = 0, yT = 0。 调整三个自由度的平动机构 (4), 即可使七孔压力探头的测量 端达到在空间上的每个测量点。在每个测量点获得七个压力孔的压力值。按照公式(1 ) - ( 4) 计算测量点的压力系数, 利用测得的压力系数和标定的压力系数数据列表进行角度插值, 获 得测量点的流动方向, 即用插值得到的测量点的 (《fl ,yT)。将测量点的空间位置、流动角度和 压力系数用图 1中的控制计算机中的数据分析和处理单元记录成文件。 The third step of the measurement is to obtain the flow direction of the measuring point with a seven-hole pressure probe. Hold the seven-hole pressure probe at the nominal position, ie = 0, yT = 0. By adjusting the translation mechanism (4) of three degrees of freedom, the measuring end of the seven-hole pressure probe can be reached at each measurement point in space. The pressure values of the seven pressure holes were obtained at each measurement point. Calculate the pressure coefficient of the measuring point according to the formula (1) - (4), and use the measured pressure coefficient and the calibrated pressure coefficient data list to perform angular interpolation to obtain the flow direction of the measuring point, that is, the measuring point obtained by interpolation (" Fl , yT). The spatial position, flow angle and pressure coefficient of the measuring points are recorded as files by the data analysis and processing unit in the control computer of Fig. 1.
测量第四步是用一维热线探头测量瞬态速度。 换下七孔压力探头 (1 ), 换上一位热线风 速仪探头 (2), 通过控制计算机(10), 在各个测量点, 按照已经记录的关于测量点的空间位 置、 流动角度的文件, 调整有两个自由度的支架*** (3 )和三个自由度的平动机构 (4), 重 新定位一维热线探头(2), 直至其沿着该测量点的流动方向, 即已知的 (《fl ,yT )。 这样, 流场 的三维流动测量被处理成当地一维流动测量。 得到的当地瞬态流动速度 , 很容易求得瞬态 速度三维分量
u - V co " cos β°; v = V ύη α° τν =— cos«。 sin 。。 ( 6 ) The fourth step in the measurement is to measure the transient velocity with a one-dimensional hot wire probe. Replace the seven-hole pressure probe (1) and replace it with a hot wire anemometer probe (2). Through the control computer (10), at each measurement point, follow the recorded data about the spatial position and flow angle of the measurement point. Adjust the two-degree-of-freedom bracket system (3) and the three-degree-of-freedom translation mechanism (4) to reposition the one-dimensional hot wire probe (2) until it flows along the measurement point, known (" fl ,yT". In this way, the three-dimensional flow measurement of the flow field is processed into a local one-dimensional flow measurement. The local transient flow velocity obtained, it is easy to find the three-dimensional component of transient velocity u - V co " cos β°; v = V ύη α° τν =— cos«. sin (6)
通过这样的测量过程, 具体是对流场的每个测量点进行了两次测量, 第一次用七孔压力 探头获得流场流动方向, 第二次用一维热线探头获得流场瞬态速度。 上述测量装置和流程适 合旋流场, 即大流动角度的流场的测量, 取代了该形势下通常需要使用的三维热线风速仪。 按照本发明提出的装置, 总的测量时间没有明显增长, 因为七孔压力探头和一维热线的测量 用时相比三维热线分别要少很多。 如果这个实施例子使用三维热线风速仪, 按照相同的角度 标定范围、 每个角度的标定时间和速度工况标定范围, 即按 400个标定角度, 每个标定角度 需 20 秒, 20个速度工况来计算, 仅标定时间就需要: 20秒 x20x400=44小时。 而本发明的 使用使测量过程简单、 快捷, 如前面提到, 标定时间不超过 3小时, 节省了 90%的时间, 极 大缩短和简化了热线标定时间和过程, 减小了测量仪器的长时间过热而带来的误差, 使测量 结果更可靠。 七孔压力探头的制作成本约为一维热线探头的 10%, 而一维热线探头的制作成 本约为三维热线探头的 1%。 因而, 用一个七孔压力探头和一个一维热线风速仪代替的三维瞬 态测量通常所使用的三维热线风速仪的方法, 降低了制造成本 95% 以上。 Through such a measurement process, specifically, each measurement point of the flow field is measured twice, the flow direction of the flow field is obtained by the first pressure probe for the first time, and the transient speed of the flow field is obtained by the second time using the one-dimensional hot line probe. . The above measuring device and flow are suitable for the swirl field, that is, the measurement of the flow field at a large flow angle, replacing the three-dimensional hot wire anemometer which is usually required in this situation. According to the device proposed by the present invention, the total measurement time is not significantly increased because the measurement of the seven-hole pressure probe and the one-dimensional hot wire is much less than that of the three-dimensional hot wire. If this embodiment uses a three-dimensional hot wire anemometer, the calibration range of the same angle, the calibration time of each angle, and the calibration range of the speed conditions, that is, according to 400 calibration angles, each calibration angle takes 20 seconds, 20 speed conditions. To calculate, only the calibration time is required: 20 seconds x 20 x 400 = 44 hours. The use of the invention makes the measurement process simple and fast. As mentioned above, the calibration time is less than 3 hours, saving 90% of the time, greatly shortening and simplifying the hot line calibration time and process, and reducing the length of the measuring instrument. The error caused by overheating makes the measurement result more reliable. The production cost of a seven-hole pressure probe is about 10% of that of a one-dimensional hot-wire probe, while the cost of a one-dimensional hot-wire probe is about 1% of that of a three-dimensional hot-wire probe. Thus, a three-dimensional transient measurement using a seven-hole pressure probe and a one-dimensional hot wire anemometer typically uses a three-dimensional hot wire anemometer method that reduces manufacturing costs by more than 95%.
附图标记列表 List of reference signs
1七孔压力探头 1 seven-hole pressure probe
2一维热线风速仪探头 2 one-dimensional hot wire anemometer probe
3有两个转动自由度的支架*** 3 bracket system with two rotational degrees of freedom
4三自由度平动机构 4 three degrees of freedom translation mechanism
5七个压力传感器 5 seven pressure sensors
6压力管 6 pressure tube
7常温电桥 7 normal temperature bridge
8导线 8 wire
9数据采集管理*** 9 data collection management system
10控制计算机 10 control computer
11中心孔 11 center hole
12周边孔 12 peripheral holes
13热丝
热丝支架 导线套筒 摆动角度《° 仰俯角度 定位夹子 蜗轮 13 hot wire Hot wire bracket wire sleeve swing angle "° pitch angle positioning clip worm wheel
蜗杆 Worm
步进电机 1号 支架 Stepper motor No. 1 bracket
传动轴 Drive shaft
止推轴承 步进电机 2号 X-方向的平动 y_方向的平动 Z-方向的平动 风洞 Thrust bearing Stepper motor No. 2 X-direction translation y_direction translation Z-direction translation Wind tunnel
风洞气流流动方向 三维机翼 风洞壁面上的小孔 信号放大器 控制线
Wind tunnel airflow direction 3D wing Small hole signal amplifier on the wall surface Control line
Claims
1. 一种测量旋流场的压力和速度的工具, 其特征在于, 包括一个七孔压力探头(1 )、 一个一 维热线风速仪探头(2)、 一个有两个转动自由度的支架***(3)、 一个三自由度平动机构A tool for measuring the pressure and velocity of a swirl field, comprising a seven-hole pressure probe (1), a one-dimensional hot wire anemometer probe (2), and a bracket system having two rotational degrees of freedom (3), a three-degree-of-freedom translation mechanism
(4)、 七个压力传感器 (5)、 压力管 (6)、 常温电桥 (7)、 导线 (8)、 数据采集管理***(4), seven pressure sensors (5), pressure tube (6), room temperature bridge (7), wire (8), data acquisition management system
(9) 及控制计算机 (10) 等部件, 上述部件的连接关系: (9) and control computer (10) and other components, the connection relationship of the above components:
七孔压力探头 (1 )和热线风速仪探头 (2)定位在有两个转动自由度的支架*** (3)上; 有两个转动自由度的支架*** (3) 固定在一个三自由度平动机构 (4) 上; The seven-hole pressure probe (1) and the hot wire anemometer probe (2) are positioned on a two-rotation degree support system (3); the two-degree-of-freedom support system (3) is fixed in a three-degree-of-freedom flat On the moving mechanism (4);
七孔压力探头 (1 )通过压力管 (6)连接到七个压力传感器 (5), 再连接到数据采集*** The seven-hole pressure probe (1) is connected to seven pressure sensors (5) via a pressure tube (6) and then connected to the data acquisition system
(9) 、 控制计算机 ( 10) ; (9), control computer (10);
一维热线风速仪探头( 2 )通过导线( 8 )连接到常温电桥( 7 ),再连接到数据采集***( 9 )、 控制计算机 (10) 。 The one-dimensional hot wire anemometer probe (2) is connected to the normal temperature bridge (7) through the wire (8), and then connected to the data acquisition system (9) and the control computer (10).
2. 根据权利要求 1所述的一种测量旋流场的压力和速度的工具, 其特征在于, 所述的七孔压 力探头 (1 ) 的外形呈长圆柱体的形状, 在其测量端端部呈圆锥台形状。 2. A tool for measuring the pressure and velocity of a swirl field according to claim 1, wherein the seven-hole pressure probe (1) has a long cylindrical shape at its measuring end. The part is in the shape of a truncated cone.
3. 根据权利要求 1所述的一种测量旋流场的压力和速度的工具, 其特征在于, 所述的一维热 线风速仪探头 (2) 外形是呈细长圆柱体的形状。 3. A tool for measuring the pressure and velocity of a swirl field according to claim 1, wherein said one-dimensional hot wire anemometer probe (2) has the shape of an elongated cylinder.
4. 根据权利要求 1所述的一种测量旋流场的压力和速度的工具, 其特征在于, 其使用过程具 体分为四步, 具体是- 第一步是七孔压力探头 (1 ) 的标定; 4. A tool for measuring the pressure and velocity of a swirl field according to claim 1, wherein the use process is specifically divided into four steps, specifically - the first step is a seven-hole pressure probe (1) Calibration
第二步是一维热线风速仪探头 (2) 的标定; The second step is the calibration of the one-dimensional hot wire anemometer probe (2);
第三步是用七孔压力探头 (1 ) 获得测量点的流动角度; The third step is to obtain the flow angle of the measuring point with a seven-hole pressure probe (1);
第四步是用一维热线风速仪探头(2)替换七孔压力探头(1 ), 沿着已知的流动角度进行
The fourth step is to replace the seven-hole pressure probe (1) with a one-dimensional hot wire anemometer probe (2), along a known flow angle.
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