CN211626374U - Blade tip clearance measuring device based on closed environment - Google Patents
Blade tip clearance measuring device based on closed environment Download PDFInfo
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- CN211626374U CN211626374U CN202020397589.4U CN202020397589U CN211626374U CN 211626374 U CN211626374 U CN 211626374U CN 202020397589 U CN202020397589 U CN 202020397589U CN 211626374 U CN211626374 U CN 211626374U
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Abstract
The utility model discloses a tip clearance measuring device based on airtight environment for nested installation is on the rotor blade that needs to detect, and rotor blade is located the quick-witted casket, and tip clearance measuring device includes capacitive sensor, detection circuitry unit, wireless transmission module, power supply battery and fastener, capacitive sensor sets up in the top of tip clearance measuring device, adjusts the radial position of tip clearance measuring device through adjusting the fastener, makes capacitive sensor's polar plate parallel with rotor blade's top; the capacitance sensor, the detection circuit unit and the wireless transmission module are sequentially connected, and the power supply battery is used for providing electric energy required by the blade tip clearance measuring device.
Description
Technical Field
The utility model relates to a apex clearance measurement field especially relates to an apex clearance measurement device based on under the airtight environment.
Background
In rotary machines such as aero-engines, gas turbines, steam turbines, etc., the minute distance between the tip of a rotor blade and the inner wall of a casing is called the tip clearance, which is one of the important parameters affecting the performance of the rotary machine. The reduction of the blade tip clearance can reduce the fuel consumption rate and obviously improve the operation efficiency of the rotary machine, but the too small blade tip clearance value can cause the collision and friction of the blade and the casing, and the operation safety of the rotary machine is seriously damaged. Therefore, the blade tip clearance measurement technology has important significance for improving the performance of the rotating machinery and guaranteeing the safe operation of the rotating machinery.
At present, mature blade tip clearance measuring methods include a discharge probe method, a laser triangulation method, an optical fiber bundle method, an eddy current method, a capacitance method and a microwave method, except the eddy current method, no hole needs to be formed when a casing is thin, sensors need to be installed on the surfaces of the casings in other methods, and clearance value measurement is achieved by measuring the distance between the top end of a blade and the top end of each sensor. The method breaks the tightness of the internal environment of the rotary machine, easily causes fluid leakage, and meanwhile, the opening of the casing is a permanent damage, and once a measuring point is replaced, the opening needs to be made again, so that great damage is caused to the rotary machine, and faults are easily caused.
In order to ensure the sealing property of the environment of the rotating machine, a common blade tip clearance measuring method is a plasticine method. The plasticine is uniformly coated on the inner wall of the casing, redundant plasticine can be cut off by the blades rotating at high speed, and the height of the residual plasticine is measured after the machine is stopped, namely the minimum value of the blade tip clearance in the working process. The method is simple to implement, low in cost and incapable of causing any damage to the rotating machinery, but the measurement precision is low, the minimum value of the clearance of the primary blade in the whole working process can be measured only, the measurement can be carried out only when the machine is started and stopped, and the real-time value of the blade tip clearance cannot be obtained.
SUMMERY OF THE UTILITY MODEL
The utility model aims at overcoming among the prior art rotary machine airtight environment and causing destruction, clearance value measurement accuracy is lower, and can only measure the clearance minimum of the whole working process of one-level rotor blade, fails to realize the shortcoming that a plurality of blade clearance values show in real time, provides one kind and is applicable to airtight environment, can realize multi-blade high accuracy, real-time, simple structure low cost's apex clearance measuring device.
The utility model aims at realizing through the following technical scheme:
a blade tip clearance measuring device based on a closed environment is used for being nested and installed on a rotor blade to be detected, the rotor blade is located in a casing, the blade tip clearance measuring device comprises a capacitance sensor, a detection circuit unit, a wireless transmission module, a power supply battery and a fastening device, the capacitance sensor is arranged at the top of the blade tip clearance measuring device, and the fastening device is adjusted to adjust the radial position of the blade tip clearance measuring device, so that a polar plate of the capacitance sensor is parallel to the top end of the rotor blade; the capacitance sensor, the detection circuit unit and the wireless transmission module are sequentially connected, and the power supply battery is used for providing electric energy required by the blade tip clearance measuring device.
Furthermore, the detection circuit unit comprises a signaling module and a main control chip.
Compared with the prior art, the utility model discloses a beneficial effect that technical scheme brought is:
1. the blade tip clearance measuring device of the utility model is installed and nested on the rotor blade to be detected, so that the blade tip clearance value of the rotor blade can be measured in the closed environment of the rotating machinery casing without punching and installing a sensor on the casing, and the damage to the rotating machinery structure is avoided;
2. the utility model discloses a blade tip clearance measuring device can send measured data to host computer through wireless transmission module in real time, therefore can be in real time on-line measurement under the high-speed rotatory state of rotor blade, overcome in traditional clearance measurement method, can only carry out the not enough of blade tip clearance measurement when opening the shut down;
3. the utility model discloses a apex clearance measuring device can send measured data to the host computer through wireless transmission module in real time, can realize the real-time on-line measurement to arbitrary rotor blade apex clearance, overcome in the traditional clearance measurement method, can only measure the not enough of apex clearance minimum in the working process;
4. the blade tip clearance measuring device of the utility model has small volume and delicate design, and can not cause structural damage to the rotating machinery, so that a plurality of measuring devices can be simultaneously installed on a single-stage blade;
5. through a wireless transmission technology, tip clearance values of a plurality of blades of the multistage rotor can be measured simultaneously;
6. through a wireless transmission technology, networking of a plurality of measuring devices can be realized, so that good technical support is provided for monitoring of the overall running state of the rotating machinery and data fusion;
7. the flexible sensing device is suitable for complex environments with different blade shapes and narrow gaps;
8. the blade tip clearance measuring device with low cost and high precision is provided for the closed environment of the rotating machinery.
Drawings
Fig. 1 shows the installation schematic diagram of the blade tip clearance measuring device of the present invention.
Fig. 2 shows a schematic structural diagram of the middle blade tip gap measuring device of the present invention.
Fig. 3 shows the flexible sensing structure diagram of the middle blade tip clearance measuring device of the present invention.
Reference numerals: 1-blade tip clearance measuring device, 2-rotor blade, 3-capacitance sensor, 4-fastening device, 5-casing, 6-power supply battery, 7-detection circuit unit, 8-wireless transmission module, 9-flexible sensing device and 10-obstacle
Detailed Description
The present invention will be described in further detail with reference to the following drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The utility model provides a apex clearance measuring device 1 based on under the airtight environment can the nested installation on the rotor blade 2 that needs detect, as shown in FIG. 1. The top end of the tip clearance measuring device 1 is provided with a capacitance sensor 3, the radial relative position of the tip clearance measuring device 1 is adjusted, the capacitance sensor 3 is just placed at the top end of the rotor blade 2 to be measured, and the polar plate of the capacitance sensor 3 is ensured to be parallel to the top end of the rotor blade 2 as far as possible. After the position of the blade tip clearance measuring device 1 is determined, the blade tip clearance measuring device is fixed on the rotor blade 2 through the fastening device 4, so that the blade tip clearance measuring device is prevented from generating play in the high-speed rotation process of the rotor blade 2 and influencing the accuracy of clearance measuring data.
The utility model discloses a apex clearance measuring device 1, based on capacitance sensor range finding technique, through measuring the electric capacity change of installing between 2 top center electrodes of rotor blade and the 5 inner walls of machine casket, calculate rotor blade 2's apex clearance value. Under the static state of the blade, the capacitance value from the central electrode of the capacitive sensor to the casing is as follows:
wherein, is dielectric constant, S is plate area, d1The distance between the central electrode of the capacitive sensor and the inner wall of the casing. Since the tip clearance measuring device 1 is fixed to the rotor blade 2 by the fastening device 4, the distance from the center electrode of the capacitive sensor 3 to the tip of the rotor blade 2 can be considered to be a fixed value d0Therefore, in the static state of the rotor, the tip clearance of the rotor blade is as follows:
d＝d1+d0
during operation, the rotor blade 2 rotates at high speed at high temperature, the strong centrifugal force and thermal stress may cause the blade to elongate, and the tip clearance measuring device 1 may move along with the rotor blade 2 in the fixed state of the fastening device 4, so that the radial relative position between the tip clearance measuring device and the rotor blade 2 may not change. However, the distance from the central electrode of the capacitive sensor 3 to the top end of the rotor blade 2 may change due to the influence of high temperature and centrifugal force, so that the blade tip clearance of the blade in the moving state of the rotor is:
d＝d1+d′0
wherein, d'0As the centre of a capacitive sensor in the rotor movementDistance of the electrode to the tip of the rotor blade. Therefore, the utility model discloses a apex clearance measuring device 1 can realize the apex clearance dynamic measurement under the high-speed motion state of rotor blade.
To sum up, apex clearance measuring device 1's structural design is very critical, the utility model discloses an apex clearance measuring device 1 structure is shown in fig. 2, by parts such as capacitive sensor 3, fastener 4, power supply battery 6, detection circuitry unit 7, wireless transmission module 8 and constitute.
First, the capacitance sensor 3 converts a displacement signal from the tip of the rotor blade 2 to the inner wall of the casing 5 into a change in capacitance value, and transmits the change to the detection circuit unit through the sensor cable. The detection circuit unit 7 then comprises a signaling module of the sensor, a main control chip and the like. The signal adjusting module of the sensor receives the capacitance signals transmitted by the sensor cable, removes noise, converts the capacitance signals into electric signals and transmits the electric signals to the main control chip. The main control chip comprises an ARM (advanced RISC machine), an FPGA (field programmable gate array) and the like, performs corresponding calculation according to the received electric signals, performs back calculation on the electric signals to obtain a blade tip clearance value, and transmits the blade tip clearance value to the wireless transmission module. And finally, the wireless transmission module 8 receives the blade tip clearance value and transmits the data to the upper computer of the system through wireless transmission. And the upper computer receives the blade tip clearance value and displays the value in the upper computer software.
The blade tip clearance measuring device 1 is powered by the battery 6, so that the normal work of the whole system is guaranteed. The blade tip clearance measuring device 1 is fixed on the rotor blade 2 through the fastening device 4, and the fastening device 4 can ensure that the measuring device 1 does not move relative to the rotor blade 2 under the severe working conditions of high temperature, high pressure and high-speed rotation.
Further, in order to enable the blade tip clearance measuring device 1 to work normally in a closed environment of the rotary machine, the blade tip clearance measuring device should be designed according to the working environment of the rotor blade of the rotary machine and with reference to the measurement requirement of the blade tip clearance.
The method comprises the following specific steps:
(1) the blade tip clearance measuring device should be designed to be small and exquisite due to the limited space on the rotor of the rotating machine in a closed environment. In order to ensure the gas flow capacity of the rotor blade, the casing height H of the tip clearance measuring device should be less than half the rotor blade radius R, i.e. less than half the rotor blade radius R
H＜0.5R
(2) When the same-stage rotor is required to measure the blade tip clearance of a plurality of blades, a plurality of blade tip clearance measuring devices are required to be installed on different blades. In order to enable the gap measuring device to be mounted on adjacent rotor blades, the width W of the device housing should be such that
Wherein N is the number of rotor blades, R is the rotor hub radius, and R is the rotor blade radius.
(3) The capacitive sensor 3 is arranged at the top end of the rotor blade 2, and the parallel of a polar plate of the capacitive sensor and the top end of the blade needs to be ensured as much as possible during installation. However, due to the influence of installation error, high temperature, high pressure or blade rotation, the polar plate of the capacitive sensor may have an inclination angle, so that the capacitive signal of the capacitive sensor has an error:
the dielectric constant is, d is a tip clearance value, a is a characteristic length of a polar plate of the capacitance sensor, and theta is a polar plate inclination angle. When the error of the capacitance signal is less than deltaC, determined by the detection capability and the calculation level of the circuit0When the inclination angle is smaller than theta, the error can be ignored or eliminated by circuit compensation, and then the inclination angle is known to be smaller than theta0When the plate is in use, the error caused by the change of the inclination angle of the plate can be ignored or eliminated by circuit compensation, wherein, Delta C0And theta0Are all constants determined by technical level and measurement accuracy requirements.
(4) In order to adapt to different application environments, the capacitance sensor has different forms, one of which is a capacitance polar plate type, namely a capacitance sensor 3, and is mainly applied to the environment with simple internal structure and no complex barrier; still another is a flexible sensing device 9, which uses flexible PCB, and is suitable for use in the environment of complicated structure with different blade shapes in the turbine or aeroengine, as shown in fig. 3. The flexible sensing device 9 can bypass the complex barrier 10, pass through a narrow gap, and be fixed on the surface of the blade through a magnet, so that the flexible sensing device cannot generate relative position movement with the rotor blade under the working condition of high-speed rotation. The working principle and design process of the flexible sensor means 9 is still as described above, except that the structure of the sensor itself is slightly different.
(5) Each tip clearance measuring device can be provided with a plurality of sensors, and can measure different positions of the same rotor blade. In addition, a plurality of blade tip clearance measuring devices can be installed on a single-stage rotor of the rotary machine, each rotary machine comprises a multi-stage rotor, and fusion of data of a plurality of measured blades of the multi-stage rotor can be realized through networking, so that the overall operation state of the rotary machine is finally obtained.
The present invention is not limited to the above-described embodiments. The above description of the embodiments is intended to describe and illustrate the technical solutions of the present invention, and the above embodiments are merely illustrative and not restrictive. Without departing from the spirit of the invention and the scope of the appended claims, the person skilled in the art can make many changes in form and detail within the teaching of the invention.
Claims (2)
1. A blade tip clearance measuring device based on a closed environment is used for being nested and installed on a rotor blade to be detected, and the rotor blade is located in a casing; the capacitance sensor, the detection circuit unit and the wireless transmission module are sequentially connected, and the power supply battery is used for providing electric energy required by the blade tip clearance measuring device.
2. The device for measuring the blade tip clearance based on the closed environment according to claim 1, wherein the detection circuit unit comprises a signal modulation module and a main control chip.
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| CN202020397589.4U CN211626374U (en) | 2020-03-25 | 2020-03-25 | Blade tip clearance measuring device based on closed environment |
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| CN202020397589.4U CN211626374U (en) | 2020-03-25 | 2020-03-25 | Blade tip clearance measuring device based on closed environment |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113671518A (en) * | 2021-08-27 | 2021-11-19 | 沈阳透平机械股份有限公司 | Wind tunnel compressor moving blade clearance measuring method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113671518A (en) * | 2021-08-27 | 2021-11-19 | 沈阳透平机械股份有限公司 | Wind tunnel compressor moving blade clearance measuring method |
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