CN113670564A - Combined probe and method for measuring flow field of interstage tip region of small compressor - Google Patents
Combined probe and method for measuring flow field of interstage tip region of small compressor Download PDFInfo
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Abstract
The invention belongs to the technical field of subsonic three-dimensional flow field parameter testing, and particularly relates to a combined probe and a method for measuring a flow field of an interstage tip region of a small compressor. The method for obtaining the three-dimensional dynamic flow field parameters of the secondary flow in the tip area between the rotating and static parts of the small compressor has important significance for designing the small compressor and improving the performance of the compressor. The testing of secondary flow dynamic parameters in the tip region of the rotating and static blades of the small compressor has the measurement difficulties of large airflow deflection angle, narrow measurement space and the like. According to the invention, two single-hole dynamic pressure probes are sequentially inserted into the same radial position of the flow field, and dynamic changes of a secondary flow airflow pitch angle, an airflow deflection angle, total pressure, static pressure and Mach number in a tip area between the rotating and static parts of the small compressor are obtained. Compared with other three-dimensional flow field dynamic parameter measuring methods, the method has the advantages of higher spatial resolution, capability of accurately measuring the dynamic change of the secondary flow parameter of the tip region between the rotating and static parts of the small compressor, small interference on the flow field of the tip region and high frequency response.
Description
Technical Field
The invention belongs to the technical field of subsonic three-dimensional flow field parameter testing, and particularly relates to a combined probe and a method for measuring a flow field of an interstage sharp region of a small compressor.
Background
The method for obtaining the secondary flow dynamic parameters of the rotating and static peak areas of the small-sized compressor has important significance for designing the small-sized compressor and improving the performance of the compressor. For the test of the three-dimensional flow field parameters in the blade tip region between the rotor and the stator of the small compressor, the flow field comprises the wake of the movable blade, the leakage vortex and other secondary flows, the flow field has strong non-stationarity and rotation property, the axial clearance of the small compressor is very small, and the size of the clearance is about 2mm, so the parameter test of the flow field in the tip region has the measurement difficulties of large airflow deflection angle, narrow measurement space and the like.
The conventional steady-state pressure probe cannot be inserted into an interstage of a small compressor for testing due to size limitation on one hand, and cannot obtain dynamic parameter information of a flow field on the other hand; the hot wire probe can measure a dynamic speed signal of a flow field, but cannot provide dynamic information of an airflow pitch angle, an airflow deflection angle, total pressure, static pressure and Mach number. In a small-sized compressor test, dynamic changes of an airflow pitch angle, an airflow deflection angle, total pressure, static pressure and a Mach number of a secondary flow field in a tip region between a rotor and a stator are preferably obtained by measuring dynamic parameters of the secondary flow in the tip region between the rotor and the stator, and the dynamic changes are used for verifying the design and flow field diagnosis of the small-sized compressor so as to improve the performance of a machine, and the probe cannot meet the current test requirement.
At present, in measuring subsonic three-dimensional flow field dynamic parameters, a porous dynamic pressure probe is generally adopted, the probe is at least provided with 2 pressure sensing holes, the head of the probe is at least used for packaging 2 dynamic pressure sensors, and due to the fact that certain intervals exist among the sensing holes, data measured by each sensing hole are not pressure values of the same space point, the space resolution of the probe is low, meanwhile, the size of the head of the porous dynamic pressure probe is limited by the size of the sensor, the size of the head of the probe is not easy to be reduced, the size of the head of the probe is large, the probe cannot be inserted into a rotor and a stator of a small-sized air compressor to be tested, the large size of the head can reduce the space resolution of the probe, the measurement precision is reduced, and the measured flow field can be seriously interfered.
The head of the single-hole dynamic pressure probe is only packaged with one pressure sensor, the head is small in size, and the probe has the potential of measuring dynamic parameters of an interstage flow field of a small compressor. At present, a few three-dimensional single-hole dynamic pressure probes are introduced, a patent 201710118903.3 introduces a single-inclined-hole dynamic pressure probe for measuring a rotor outlet subsonic three-dimensional flow field, the head of the probe is a cylinder and a chamfer which share a bottom surface, a patent 201710115438.8 introduces a conical single-hole dynamic pressure probe for measuring a rotor outlet transonic three-dimensional flow field, and the head of the probe is a cylinder and a cone which share a bottom surface. The head sizes of the two probes are larger, so that the probes cannot be inserted into the small-sized gas compressor to measure the dynamic change of flow field parameters between static measurement and rotating measurement on one hand, and the spatial resolution of the probes is lower on the other hand; the transition angle of the joint of the cylinder at the head part of the probe, the beveling body and the cone is overlarge, and when the airflow angle of incoming flow is large, the airflow is easy to separate near the head part of the probe, so that the measured flow field is seriously disturbed; when the probe is used for measuring the dynamic pressure of a three-dimensional flow field close to the end wall, the incoming flow bypasses the cylinder to generate horseshoe vortex, and the horseshoe vortex can reduce the test precision of the probe; the beveling body and the tip end of the cone have small space, and the dynamic pressure sensor cannot be arranged close to the pressure sensing hole, so that a cavity between the pressure sensing hole and the sensor is large, the cavity effect is obvious, and the frequency response of the probe is low; in the process of measuring the dynamic parameters of the three-dimensional flow field, the single-hole dynamic pressure probe needs to rotate along the axis of the strut at more angular positions, which increases the complexity of measurement, and the two probes have no claim about positioning blocks. Therefore, the two patent applications cannot be applied to the measurement of the dynamic parameters of the secondary flow three-dimensional flow field in the rotating and static tip areas of the small compressor.
There are few descriptions about probe positioning blocks, for example, patent 201710200518.3 describes a pressure probe positioning block, in which a bubble level is sleeved on one side of the base of the positioning block, and the positioning block has the disadvantages of large size, single positioning surface, etc.
Therefore, in order to measure the dynamic changes of the airflow pitch angle, the airflow deflection angle, the total pressure, the static pressure and the mach number of the secondary flow three-dimensional flow field in the rotating and static tip area of the small-sized compressor, the development of a small-size dynamic pressure probe with a positioning function is urgently needed.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: and acquiring secondary flow dynamic parameters of a rotating and static tip region of the small compressor, wherein the secondary flow dynamic parameters comprise three-dimensional flow parameters such as an airflow pitch angle, an airflow deflection angle, total pressure, static pressure, Mach number and the like. The combined probe consists of two single-hole dynamic pressure probes, the two single-hole dynamic pressure probes which are calibrated through a wind tunnel are sequentially inserted into the same radial position of the flow field for measurement, the circle centers of pressure sensing holes of the two probes are ensured to be positioned at the same spatial point, and dynamic changes of secondary flow pitch angle, flow deflection angle, total pressure, static pressure and Mach number of a rotating and static tip region of the small compressor are obtained through the combination of the two probes. Compared with other three-dimensional flow field dynamic parameter measuring methods, the method has the advantages of higher spatial resolution, capability of accurately measuring the dynamic change of the secondary flow field parameters in the tip region between the rotating and static parts of the small compressor, small interference on the flow field of the tip region and high frequency response.
The technical solution of the invention is as follows:
1. the pressure probe consists of two single-hole dynamic pressure probes, namely a positive-hole single-hole dynamic pressure probe and an inclined-hole single-hole dynamic pressure probe; the two single-hole dynamic pressure probes are composed of probe heads (1), supporting rods (2), dynamic pressure sensors (6) and positioning blocks (8); the probe head (1) consists of a cylinder (3) and an arc rotating body (4) which share the same bottom surface, the arc rotating body (4) is formed by rotating an arc AB around a shaft OB, the shaft OB is perpendicular to a tangent line of a point B and is superposed with the axis of the cylinder (3), and the arc AB is between 1/8 and 1/4; a probe head (1) of the positive hole type pressure probe is provided with a pressure sensing hole which is a positive hole (5); the probe head (1) of the inclined hole type pressure probe is provided with a pressure sensing hole which is an inclined hole (14); pressure sensing holes of the two pressure probes are communicated with a dynamic pressure sensor (6) packaged in the probe head (1), the central line of the pressure sensing hole and the axis of the cylinder of the probe head (1) are on the same plane, and the axis of the cylinder of the probe head (1) is superposed with the axis of the probe supporting rod (2);
2. furthermore, the diameter of the cylinder (3) at the head part (1) of the probe is d, the value range of d is more than or equal to 1.2mm and less than or equal to 2mm, and the length is 4d to 8 d; the diameter of the pressure sensing hole is 0.2mm to 0.4mm, and the central line of the positive hole (5) and the axis of the cylinder (3) of the probe head (1)The included angle is 90 degrees, the included angle between the central line of the inclined hole (14) and the axis of the cylinder (3) of the probe head (1) is theta, and the value range is more than or equal to 0 degree and less than 90 degrees; the vertical distance from the interface of the cylinder (3) at the head part of the positive hole type single-hole dynamic pressure probe and the revolution body (4) to the lowest point of the revolution body (4) is hzThe vertical distance from the center of the main hole (5) to the lowest point of the rotating body (4) is h1The value range is hz≤h1D is less than or equal to d; the vertical distance from the interface of the cylinder (3) at the head part of the inclined hole type single-hole dynamic pressure probe and the revolution body (4) to the lowest point of the revolution body (4) is hxThe vertical distance from the circle center of the inclined hole (14) to the lowest point of the rotating body (4) is h2The value range is not less than 0 h2<hx；
3. Furthermore, the probe supporting rod (2) is a cylinder, the diameter of the probe supporting rod is D, the value range of D is more than or equal to 2mm and less than or equal to 4mm, a circular pipeline is arranged in the probe supporting rod, a cable (7) of the dynamic pressure sensor packaged in the head part (1) of the probe is led out of the tail part of the probe through the pipeline in the probe supporting rod (2), and the tail parts of the two single-hole dynamic pressure probes are sleeved with a positioning block (8);
4. furthermore, the positioning block (8) is of an integral structure and comprises a cuboid base (9), a cylindrical boss (10), a through hole (11) and threaded holes (12), the positioning block (8) is sleeved at the tail of the probe through the through hole (11) and fixed by a countersunk screw (13) penetrating through the threaded holes (12) on two sides of the boss (10), and the countersunk screw (13) is completely embedded into the threaded holes (12); the rectangular base (9) comprises four rectangular side surfaces and two square bottom surfaces, two adjacent side surfaces in the four side surfaces are perpendicular to each other, the four side surfaces can be used as positioning surfaces, one bottom surface in the base (9) is connected with a cylindrical boss (10), a perpendicular bisector of the bottom surface is superposed with the axis of the boss (10), the axis of the boss (10) is superposed with the central line of a through hole (11), the diameter of the through hole is D +0.05mm, the outer diameter of the boss is M, the value range is D +2mm or more and less than or equal to D +5mm, the side length of the bottom surface of the base (9) is M to M +3mm, the thickness of the base (9) is H, and the value range is 2mm or more and less than or equal to H and less than or equal to 5 mm;
5. furthermore, before measurement, the two probes are respectively calibrated in a subsonic calibration wind tunnel, one side surface of a base (9) of a positioning block (8) is selected as a positioning surface, the relative position of the positioning surface of the positioning block (8) and a pressure sensing hole is determined through a level gauge, the positioning block (8) is fixed through a countersunk head screw (13), and the pneumatic calibration coefficients of the probes are obtained in different incoming flow directions and different Mach numbers;
6. further, during measurement, firstly, a positive hole type single-hole dynamic pressure probe is installed and fixed on a displacement mechanism, and the specific process is that a level gauge is utilized to adjust the level of a positioning surface of the displacement mechanism, the probe is installed on the displacement mechanism, the level gauge is placed on the positioning surface of a probe positioning block (8), the probe is rotated along the axis of a probe supporting rod (2), the level of the positioning surface is adjusted through the level gauge, the relative position of the central line of a positive hole (5) and the positioning surface of the displacement mechanism is determined, and the probe is fixed on the displacement mechanism;
7. further, the inclined hole type single-hole dynamic pressure probe is installed and fixed on another displacement mechanism, the specific process is that a positioning surface of the displacement mechanism is adjusted to be horizontal by a level gauge, the inclined hole type single-hole dynamic pressure probe is installed on the displacement mechanism, the level gauge is placed on the positioning surface of a probe positioning block (8), the probe is rotated along the axis of a probe supporting rod (2), the level of the positioning surface is adjusted by the level gauge, the relative position of the central line of an inclined hole (14) and the positioning surface of the displacement mechanism is determined, and the probe is fixed on the displacement mechanism;
8. further, a displacement mechanism for installing a positive hole type single-hole dynamic pressure probe is installed on a casing (21) of the small compressor to be detected through a positioning device, the displacement mechanism is adjusted to insert the probe into a certain radial position of a flow field in a rotating and static interval of the small compressor, the probe is adjusted through the displacement mechanism according to a known average incoming flow direction, a positive hole (5) is aligned with the average incoming flow direction, the position is taken as a reference, the displacement mechanism is utilized to drive the probe to rotate around the axis of a probe supporting rod (2) for 1 angle in the counterclockwise direction and the clockwise direction respectively, the rotation angle is 30-45 degrees, 3 angle positions are measured in total, a data acquisition system (15) acquires dynamic pressure according to shaft pulse triggering phase locking, the triggering acquisition process is that a shaft encoder (17) is installed at the tail part of a rotating shaft of the small compressor, the rotating shaft (20) of the small compressor is connected with the rotating shaft encoder (17), the small-sized compressor rotating shaft (20) rotates to drive the rotor (18) to rotate and simultaneously drives the shaft encoder (17) to rotate, when the probe pressure sensing hole moves to a certain circumferential position relative to the rotor (18), through program control, the shaft encoder (17) outputs a pulse signal to the synchronizer (16), the synchronizer (16) outputs a pulse trigger acquisition signal to the data acquisition system (15), the data acquisition system (15) controls the pressure probe to acquire pressure, shaft pulse trigger phase-locked acquisition strictly ensures that each data acquisition is started from the same circumferential position (same phase) of a rotor coordinate system, dynamic pressure signals of 1000-2000 revolutions are acquired, and the airflow deflection angle, total pressure, static pressure and Mach number of the position are acquired according to a calibration coefficient in a calibration wind tunnel;
9. further, a displacement mechanism provided with a normal-hole type single-hole dynamic pressure probe is taken down, the displacement mechanism provided with an inclined-hole type single-hole dynamic pressure probe is arranged at the same position of a small compressor casing (21) through a positioning device, the displacement mechanism is adjusted to insert the probe into the same radial position of a flow field of a rotating and static middle sharp area of the small compressor, the probe is adjusted through the displacement mechanism according to the known average incoming flow direction, the inclined hole (14) is aligned to the average incoming flow direction, the circle center of the inclined hole (14) and the circle center of the normal hole (5) at the reference position are ensured to be located at the same spatial point, in the position, a data acquisition system (15) triggers phase locking according to shaft pulse to acquire dynamic pressure, acquires dynamic pressure signals of 1000-2000 revolutions, and acquires an airflow pitch angle of the position according to a calibration coefficient in a calibration wind tunnel;
10. and further, inserting the probes into different radial positions of a flow field, and repeating the measuring steps to obtain dynamic changes of a pitch angle, an airflow deflection angle, total pressure, static pressure and Mach number of the secondary flow airflow in a tip area between the rotating and static parts of the small-sized compressor.
The invention has the beneficial effects that:
the beneficial effects are that: the method is characterized in that the flow field parameters of the tip region between the rotating and static parts of the small-sized compressor are measured, a probe needs to be inserted into the flow field, the axial clearance between the rotating and static parts of the small-sized compressor is very small, the clearance range is about 2mm, the head of the three-dimensional porous/single-hole dynamic pressure probe is too large at present, and the dynamic change of the flow field parameters of the tip region between the rotating and static parts of the small-sized compressor cannot be inserted; the two single-hole dynamic pressure probes adopted by the invention have small sizes, can be inserted into a rotating and static tip region of a small-sized gas compressor to measure flow field parameters, and are combined for use, so that the functions of measuring three-dimensional flow field airflow pitch angle, airflow deflection angle, total pressure, static pressure and Mach number dynamic change of the rotating and static tip region are realized;
the beneficial effects are that: compared with other porous dynamic pressure probes, the dynamic pressure probe has the advantages that the size of the head of the probe is relatively small, the circle centers of the pressure sensing holes of the two probes are located at the same spatial point, the spatial resolution of the probe is high, the measurement accuracy is high, the influence of the velocity gradient and the pressure gradient of the flow field of the tip area of the small-sized gas compressor on the measurement result of the probe is avoided, when the probe is inserted into the measured flow field for measurement, the interference of the probe on the measured flow field is small, and the influence on the performance of a measured object is small;
the beneficial effects are three: when the airflow flows through the surface of the arc spinning body, the special structure of the arc spinning body can inhibit the airflow separation on the surface of the airflow and weaken the interference of the streaming around the head of the supporting rod on the flow field of the sharp area on one hand, and on the other hand, when the flow field parameter measurement is carried out near the end wall, the invention can inhibit the scale of the horseshoe vortex at the front end of the head of the probe and improve the measurement precision;
the beneficial effects are four: because the head of the probe adopts a special structure of an arc spinning body, the space of the tip of the head is larger, so that a pressure sensor in the inclined-hole dynamic pressure probe can be installed closer to a pressure sensing hole, a cavity between the sensor and the pressure sensing hole is smaller, the cavity effect is not obvious, the frequency response of the probe is high and can reach 50kHz-60 kHz;
the beneficial effects are five: compared with other probe positioning blocks, the positioning block adopted by the invention has small size, has small influence on the probe in the measuring process, can be replaced with each other because the four side surfaces can be used as positioning surfaces, has simple and convenient positioning process and is more suitable for engineering application.
Drawings
FIG. 1 is a schematic view of two single-hole dynamic pressure probes.
Fig. 2 shows a process of forming a circular arc line revolution body.
FIG. 3 is a schematic view of a positive bore, single bore dynamic pressure probe.
Fig. 4 is a partially enlarged view of fig. 3.
Fig. 5 is a top view of fig. 3.
FIG. 6 is a schematic view of a slant hole type single hole dynamic pressure probe.
Fig. 7 is a partially enlarged view of fig. 6.
Fig. 8 is a top view of fig. 6.
Fig. 9 is a schematic diagram of a trigger acquisition process.
Wherein: 1-probe head, 2-probe support rod, 3-cylinder, 4-arc rotation body, 5-positive hole, 6-dynamic pressure sensor, 7-cable of dynamic pressure sensor, 8-positioning block, 9-cuboid base, 10-cylinder boss, 11-through hole, 12-threaded hole, 13-countersunk screw, 14-inclined hole, 15-data acquisition system, 16-synchronizer, 17-shaft encoder, 18-compressor rotor, 19-compressor stator, 20-compressor rotating shaft, 21-compressor box and 22-compressor hub.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
As shown in fig. 3 and fig. 6, a positive hole type single-hole dynamic pressure probe and an inclined hole type single-hole dynamic pressure probe are respectively arranged; the two single-hole dynamic pressure probes are composed of probe heads (1), supporting rods (2), dynamic pressure sensors (6) and positioning blocks (8); the probe head (1) consists of a cylinder (3) and an arc rotating body (4) which share the same bottom surface, as shown in fig. 2, the arc rotating body (4) is formed by rotating an arc AB around an axis OB, the axis OB is perpendicular to a tangent line of a point B and is superposed with the axis of the cylinder (3), and the arc AB is 1/4 circumference; a probe head (1) of the positive hole type pressure probe is provided with a pressure sensing hole which is a positive hole (5); the probe head (1) of the inclined hole type pressure probe is provided with a pressure sensing hole which is an inclined hole (14); pressure sensing holes of the two pressure probes are communicated with a dynamic pressure sensor (6) packaged in the probe head (1), the central line of the pressure sensing hole and the axis of the cylinder of the probe head (1) are on the same plane, and the axis of the cylinder of the probe head (1) is superposed with the axis of the probe supporting rod (2);
as shown in fig. 4 and 7, the diameter of the cylinder (3) of the probe head (1) is 1.5mm, and the length is 9 mm; the diameter of the pressure sensing hole is 0.3mm, the included angle between the central line of the positive hole (5) and the axis of the cylinder (3) of the probe head (1) is 90 degrees, and the included angle between the central line of the inclined hole (14) and the axis of the cylinder (3) of the probe head (1) is 65 degrees; the vertical distance from the interface of the cylinder (3) at the head of the positive hole type single-hole dynamic pressure probe and the revolution body (4) to the lowest point of the revolution body (4) is 0.75mm, and the vertical distance from the circle center of the positive hole (5) to the lowest point of the revolution body (4) is 0.9 mm; the vertical distance from the interface of the cylindrical body (3) at the head part of the inclined hole type single-hole dynamic pressure probe and the revolution body (4) to the lowest point of the revolution body (4) is 0.75mm, and the vertical distance from the circle center of the inclined hole (14) to the lowest point of the revolution body (4) is 0.4 mm.
The probe supporting rod (2) is a cylinder, the diameter of the probe supporting rod is 3mm, a circular pipeline is arranged in the probe supporting rod, a cable (7) of a dynamic pressure sensor packaged in the probe head (1) is led out of the tail of the probe through the pipeline in the probe supporting rod (2), and the tail of each of the two single-hole dynamic pressure probes is sleeved with a positioning block (8);
the positioning block (8) is of an integrated structure and comprises a cuboid base (9), a cylindrical boss (10), a through hole (11) and threaded holes (12), the through hole (11) is sleeved at the tail of the probe supporting rod (2), a countersunk screw (13) penetrates through the threaded holes (12) on the two sides of the boss (10) to be fixed, and the countersunk screw (13) is completely embedded into the threaded holes (12);
the rectangular base (9) comprises four rectangular side surfaces and two square bottom surfaces, adjacent side surfaces in the four side surfaces are perpendicular to each other, the four side surfaces can be used as positioning surfaces, one bottom surface in the base (9) is connected with a cylindrical boss (10), the perpendicular bisector of the bottom surface is superposed with the axis of the boss (10), the axis of the boss (10) is superposed with the central line of a through hole (11), the diameter of the through hole is 3.05mm, the outer diameter of the boss is 6mm, the side length of the bottom surface of the base (9) is 8mm, and the thickness of the base (9) is 3 mm;
before measurement, the two probes are respectively calibrated in a subsonic calibration wind tunnel, one side surface of a base (9) of a positioning block (8) is selected as a positioning surface, the relative position of the positioning surface of the positioning block (8) and a pressure sensing hole is determined through a level gauge, the positioning block (8) is fixed through a countersunk screw (13), and the pneumatic calibration coefficients of the probes are obtained in different incoming flow directions and different Mach numbers;
during measurement, firstly, a positive hole type single-hole dynamic pressure probe is installed and fixed on a displacement mechanism, the specific process is that a positioning surface of the displacement mechanism is adjusted to be horizontal by a level gauge, the probe is installed on the displacement mechanism, the level gauge is placed on the positioning surface of a probe positioning block (8), the probe is rotated along the axis of a probe supporting rod (2), the level of the positioning surface is adjusted by the level gauge, the relative position of the central line of a positive hole (5) and the positioning surface of the displacement mechanism is determined, and the probe is fixed on the displacement mechanism;
the inclined hole type single-hole dynamic pressure probe is installed and fixed on another displacement mechanism, the specific process is that a positioning surface of the displacement mechanism is adjusted to be horizontal by a level gauge, the inclined hole type single-hole dynamic pressure probe is installed on the displacement mechanism, the level gauge is placed on the positioning surface of a probe positioning block (8), the probe is rotated along the axis of a probe supporting rod (2), the level of the positioning surface is adjusted by the level gauge, the relative position of the central line of an inclined hole (14) and the positioning surface of the displacement mechanism is determined, and the probe is fixed on the displacement mechanism;
then, a displacement mechanism provided with a positive hole type single-hole dynamic pressure probe is arranged on a casing (21) of the small compressor to be detected through a positioning device, the displacement mechanism is adjusted to insert the probe into a certain radial position of a flow field in a rotating and static tip region of the small compressor, as shown in figure 9, according to the known average incoming flow direction, the probe is adjusted through the displacement mechanism, a positive hole (5) is aligned with the average incoming flow direction, the position is taken as a reference, the displacement mechanism is utilized to drive the probe to rotate around the axis of a probe supporting rod (2) in the counterclockwise direction and the clockwise direction by 1 angle respectively, the rotation angle is 40 degrees, 3 angular positions are measured in total, under each angular position, a data acquisition system (15) triggers phase locking according to shaft pulses to acquire dynamic pressure, the triggering acquisition process is that a shaft encoder (17) is arranged at the tail part of a rotating shaft of the small compressor, the rotating shaft (20) of the small compressor is connected with the rotating shaft encoder (17), the small-sized compressor rotating shaft (20) rotates to drive the rotor (18) to rotate and simultaneously drives the shaft encoder (17) to rotate, when the probe pressure sensing hole moves to a certain circumferential position relative to the rotor (18), through program control, the shaft encoder (17) outputs a pulse signal to the synchronizer (16), the synchronizer (16) outputs a pulse trigger acquisition signal to the data acquisition system (15), the data acquisition system (15) controls the pressure probe to acquire pressure, shaft pulse trigger phase-locked acquisition strictly ensures that each data acquisition is started from the same circumferential position (same phase) of a rotor coordinate system, dynamic pressure signals of 1000-2000 revolutions are acquired, and the airflow deflection angle, total pressure, static pressure and Mach number of the position are acquired according to a calibration coefficient in a calibration wind tunnel;
taking down a displacement mechanism provided with a positive hole type single-hole dynamic pressure probe, installing the displacement mechanism provided with an inclined hole type single-hole dynamic pressure probe at the same position of a small compressor casing (21) through a positioning device, adjusting the displacement mechanism to insert the probe into the same radial position of a tip area flow field between rotating and static parts of a compressor, adjusting the probe through the displacement mechanism according to a known average incoming flow direction to enable an inclined hole (14) to be aligned with the average incoming flow direction, ensuring that the circle center of the inclined hole (14) and the circle center of a positive hole (5) at a reference position are located at the same spatial point, triggering a phase lock by a data acquisition system (15) according to axial pulses to acquire dynamic pressure, acquiring dynamic pressure signals of 1000-2000 revolutions, and acquiring an airflow pitch angle at the position according to a calibration coefficient in a calibration wind tunnel;
and finally, inserting the probes into different radial positions of the flow field, and repeating the measuring steps to obtain the dynamic changes of the pitch angle, the deflection angle, the total pressure, the static pressure and the Mach number of the secondary flow in the rotating and static tip region of the small-sized compressor.
Claims (1)
1. A combined probe and a method for measuring a flow field of an interstage tip region of a small compressor are characterized in that:
the combined probe consists of two single-hole dynamic pressure probes, namely a positive-hole single-hole dynamic pressure probe and an inclined-hole single-hole dynamic pressure probe; the two single-hole dynamic pressure probes are composed of probe heads (1), supporting rods (2), dynamic pressure sensors (6) and positioning blocks (8); the probe head (1) consists of a cylinder (3) and an arc rotating body (4) which share the same bottom surface, the arc rotating body (4) is formed by rotating an arc AB around a shaft OB, the shaft OB is perpendicular to a tangent line of a point B and is superposed with the axis of the cylinder (3), and the arc AB is between 1/8 and 1/4; a probe head (1) of the positive hole type pressure probe is provided with a pressure sensing hole which is a positive hole (5); the probe head (1) of the inclined hole type pressure probe is provided with a pressure sensing hole which is an inclined hole (14); pressure sensing holes of the two pressure probes are communicated with a dynamic pressure sensor (6) packaged in the probe head (1), the central line of the pressure sensing hole and the axis of the cylinder of the probe head (1) are on the same plane, and the axis of the cylinder of the probe head (1) is superposed with the axis of the probe supporting rod (2);
the diameter of the cylinder (3) of the probe head (1) is d, the range of d is more than or equal to 1.2mm and less than or equal to 2mm, and the length is 4d to 8 d; the diameter of the pressure sensing hole is 0.2mm to 0.4mm, the included angle between the central line of the positive hole (5) and the axis of the cylinder (3) of the probe head (1) is 90 degrees, the included angle between the central line of the inclined hole (14) and the axis of the cylinder (3) of the probe head (1) is theta, and the value range is that theta is more than or equal to 0 degree and less than 90 degrees; the vertical distance from the interface of the cylinder (3) at the head part of the positive hole type single-hole dynamic pressure probe and the revolution body (4) to the lowest point of the revolution body (4) is hzThe vertical distance from the center of the main hole (5) to the lowest point of the rotating body (4) is h1The value range is hz≤h1D is less than or equal to d; the vertical distance from the interface of the cylinder (3) at the head part of the inclined hole type single-hole dynamic pressure probe and the revolution body (4) to the lowest point of the revolution body (4) is hxThe vertical distance from the circle center of the inclined hole (14) to the lowest point of the rotating body (4) is h2The value range is not less than 0 h2<hx；
The probe supporting rod (2) is a cylinder, the diameter of the probe supporting rod is D, the value range of D is more than or equal to 2mm and less than or equal to 4mm, a circular pipeline is arranged in the probe supporting rod, a cable (7) of a dynamic pressure sensor packaged in the head part (1) of the probe is led out of the tail part of the probe through the pipeline in the probe supporting rod (2), and the tail parts of two kinds of single-hole dynamic pressure probes are sleeved with a positioning block (8);
the positioning block (8) is of an integrated structure and comprises a cuboid base (9), a cylindrical boss (10), a through hole (11) and a threaded hole (12), the positioning block (8) is sleeved at the tail of the probe through the through hole (11) and fixed by a countersunk screw (13) penetrating through the threaded holes (12) on two sides of the boss (10), and the countersunk screw (13) is completely embedded into the threaded hole (12); the rectangular base (9) comprises four rectangular side surfaces and two square bottom surfaces, two adjacent side surfaces in the four side surfaces are perpendicular to each other, the four side surfaces can be used as positioning surfaces, one bottom surface in the base (9) is connected with a cylindrical boss (10), a perpendicular bisector of the bottom surface is superposed with the axis of the boss (10), the axis of the boss (10) is superposed with the central line of a through hole (11), the diameter of the through hole is D +0.05mm, the outer diameter of the boss is M, the value range is D +2mm or more and less than or equal to D +5mm, the side length of the bottom surface of the base (9) is M to M +3mm, the thickness of the base (9) is H, and the value range is 2mm or more and less than or equal to H and less than or equal to 5 mm;
before measurement, the two probes are respectively calibrated in a subsonic calibration wind tunnel, one side surface of a base (9) of a positioning block (8) is selected as a positioning surface, the relative position of the positioning surface of the positioning block (8) and a pressure sensing hole is determined through a level gauge, the positioning block (8) is fixed through a countersunk screw (13), and the pneumatic calibration coefficients of the probes are obtained in different incoming flow directions and different Mach numbers;
during measurement, firstly, a positive hole type single-hole dynamic pressure probe is installed and fixed on a displacement mechanism, the specific process is that a positioning surface of the displacement mechanism is adjusted to be horizontal by a level gauge, the probe is installed on the displacement mechanism, the level gauge is placed on the positioning surface of a probe positioning block (8), the probe is rotated along the axis of a probe supporting rod (2), the level of the positioning surface is adjusted by the level gauge, the relative position of the central line of a positive hole (5) and the positioning surface of the displacement mechanism is determined, and the probe is fixed on the displacement mechanism;
the inclined hole type single-hole dynamic pressure probe is installed and fixed on another displacement mechanism, the specific process is that a positioning surface of the displacement mechanism is adjusted to be horizontal by a level gauge, the inclined hole type single-hole dynamic pressure probe is installed on the displacement mechanism, the level gauge is placed on the positioning surface of a probe positioning block (8), the probe is rotated along the axis of a probe supporting rod (2), the level of the positioning surface is adjusted by the level gauge, the relative position of the central line of an inclined hole (14) and the positioning surface of the displacement mechanism is determined, and the probe is fixed on the displacement mechanism;
then, a displacement mechanism provided with a positive hole type single-hole dynamic pressure probe is arranged on a casing (21) of the small compressor to be detected through a positioning device, the displacement mechanism is adjusted to insert the probe into a certain radial position of a flow field in a rotating and static tip region of the small compressor, the probe is adjusted through the displacement mechanism according to a known average incoming flow direction, a positive hole (5) is aligned with the average incoming flow direction, the displacement mechanism is used as a reference to drive the probe to rotate around the axis of a probe supporting rod (2) by an angle in the counterclockwise direction and the clockwise direction respectively, the rotation angle is 30-45 degrees, 3 angular positions are measured in total, a data acquisition system (15) acquires dynamic pressure according to shaft pulse triggering phase locking at each angular position, the triggering acquisition process is that a shaft encoder (17) is arranged at the tail part of a rotating shaft of the small compressor, and the rotating shaft (20) of the small compressor is connected with the rotating shaft encoder (17), the small-sized compressor rotating shaft (20) rotates to drive the rotor (18) to rotate and simultaneously drives the shaft encoder (17) to rotate, when the probe pressure sensing hole moves to a certain circumferential position relative to the rotor (18), through program control, the shaft encoder (17) outputs a pulse signal to the synchronizer (16), the synchronizer (16) outputs a pulse trigger acquisition signal to the data acquisition system (15), the data acquisition system (15) controls the pressure probe to acquire pressure, shaft pulse trigger phase-locked acquisition strictly ensures that each data acquisition is started from the same circumferential position (same phase) of a rotor coordinate system, dynamic pressure signals of 1000-2000 revolutions are acquired, and the airflow deflection angle, total pressure, static pressure and Mach number of the position are acquired according to a calibration coefficient in a calibration wind tunnel;
taking down a displacement mechanism provided with a positive hole type single-hole dynamic pressure probe, installing the displacement mechanism provided with an inclined hole type single-hole dynamic pressure probe at the same position of a small compressor casing (21) through a positioning device, adjusting the displacement mechanism to insert the probe into the same radial position of a tip area flow field between rotating and static parts of a compressor, adjusting the probe through the displacement mechanism according to a known average incoming flow direction to enable an inclined hole (14) to be aligned with the average incoming flow direction, ensuring that the circle center of the inclined hole (14) and the circle center of a positive hole (5) at a reference position are located at the same spatial point, triggering a phase lock by a data acquisition system (15) according to axial pulses to acquire dynamic pressure, acquiring dynamic pressure signals of 1000-2000 revolutions, and acquiring an airflow pitch angle at the position according to a calibration coefficient in a calibration wind tunnel;
and finally, inserting the probes into different radial positions of the flow field, and repeating the measuring steps to obtain the dynamic changes of the pitch angle, the deflection angle, the total pressure, the static pressure and the Mach number of the secondary flow in the rotating and static tip region of the small-sized compressor.
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| CN202110830166.6A CN113670564A (en) | 2021-07-22 | 2021-07-22 | Combined probe and method for measuring flow field of interstage tip region of small compressor |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115452313A (en) * | 2022-11-14 | 2022-12-09 | 中国空气动力研究与发展中心高速空气动力研究所 | Method for quickly calibrating angular sensitivity of probe in sonic explosion test |
| CN116658451A (en) * | 2023-08-02 | 2023-08-29 | 中国航发四川燃气涡轮研究院 | Method for correcting total pressure of outlet of air compressor in core machine environment based on wake loss |
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2021
- 2021-07-22 CN CN202110830166.6A patent/CN113670564A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115452313A (en) * | 2022-11-14 | 2022-12-09 | 中国空气动力研究与发展中心高速空气动力研究所 | Method for quickly calibrating angular sensitivity of probe in sonic explosion test |
| CN116658451A (en) * | 2023-08-02 | 2023-08-29 | 中国航发四川燃气涡轮研究院 | Method for correcting total pressure of outlet of air compressor in core machine environment based on wake loss |
| CN116658451B (en) * | 2023-08-02 | 2023-10-03 | 中国航发四川燃气涡轮研究院 | Method for correcting total pressure of outlet of air compressor in core machine environment based on wake loss |
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