Response bandwidth measuring device of capacitive blade tip clearance measuring system based on bipolar plate rotating structure

Abstract

The utility model discloses a response bandwidth measuring device of a capacitance type blade tip clearance measuring system based on a bipolar plate rotating structure, the blade tip clearance measuring system is composed of a capacitance sensor, a measuring system host and an upper computer which are connected in sequence, and the measuring system host comprises a signal demodulation module and an acquisition module; the response bandwidth measuring device comprises a sensitive polar plate, a receiving polar plate, a rotating table, a displacement table and a blocking capacitor; the rotating table comprises a rotating shaft, a mounting seat and a controller; the controller is used for controlling the rotating speed of the rotating shaft and displaying the rotating speed in real time; the supporting rod on the mounting seat is sleeved with a displacement table; the rotating shaft is rotatably mounted on the mounting seat; the sensitive polar plate is fixed on the rotating shaft as a rotating component; the receiving polar plate is fixedly arranged on the displacement table and is positioned above the sensitive polar plate; the distance between the receiving polar plate and the sensitive polar plate is changed by adjusting the height of the displacement table; and the receiving pole plate is sequentially connected with a blocking capacitor and a core pole of a tri-coaxial cable.

Description

TECHNICAL FIELD

[0001] The utility model relates to tip clearance measurement field especially relates to a capacitive tip clearance measurement system bandwidth measuring device based on bipolar plate rotation structure. BACKGROUND

[0002] In rotating machinery such as aero-engine, gas turbine and steam turbine, the tiny distance between the rotor blade top end and the inner wall of the casing is called tip clearance, which is one of the important parameters affecting the performance of rotating machinery, and the tip clearance measurement technology is of great significance to improve the performance of rotating machinery and ensure the safe operation of rotating machinery. The capacitive tip clearance measurement method is widely used in tip clearance engineering test because of its advantages of high temperature resistance, gas corrosion resistance, low intervention, non-contact, online and real-time.

[0003] The capacitive tip clearance measurement system is composed of a capacitive sensor, a cable, a gap signal demodulation module, an acquisition and processing module and upper computer software, and is based on the parallel plate capacitor principle. The tip clearance is measured by measuring the capacitance between the sensor core and the rotor tip. Since the capacitive tip clearance measurement system is an online measurement, in order to ensure the measurement accuracy and resolution at the highest speed of the rotating blade, the measurement system is required to have a high response bandwidth, and how to accurately measure the system response bandwidth becomes a key problem to be solved.

[0004] In order to measure the response bandwidth of the system, test signals of different frequencies are generally generated to simulate the system input, and the amplitude change of the system output signal is observed. However, the input signal of the capacitive tip clearance measurement system is the capacitance signal between the sensor core and the rotor blade, and the existing devices and methods cannot generate standard capacitance signals to simulate system input. If the voltage test signal is used as the input signal, the system capacitance-voltage conversion process will be ignored, resulting in low measurement accuracy of the system response bandwidth. UTILITY MODEL CONTENTS

[0005] The utility model aims at overcoming the shortcomings of the prior art that the existing devices cannot generate standard capacitance signals to simulate system input, and directly using standard voltage signals as input will ignore the influence of system capacitance-voltage conversion on response bandwidth, resulting in low measurement accuracy of response bandwidth, and provides a measuring device capable of directly generating standard capacitance signals to realize high-precision measurement of system response bandwidth.

[0006] The utility model aims at overcoming the shortcomings of the prior art that the existing devices cannot generate standard capacitance signals to simulate system input, and directly using standard voltage signals as input will ignore the influence of system capacitance-voltage conversion on response bandwidth, resulting in low measurement accuracy of response bandwidth, and provides a measuring device capable of directly generating standard capacitance signals to realize high-precision measurement of system response bandwidth.

[0007] A response bandwidth measuring device of a capacitive tip clearance measuring system based on a bipolar plate rotating structure, the capacitive tip clearance measuring system is composed of a capacitive sensor, a measuring system host and an upper computer connected in turn, the measuring system host comprises a signal demodulation module and an acquisition module, the capacitive sensor is composed of a sensor probe and a three coaxial cable connected with each other, the three coaxial cable comprises two sections of long and short, the three coaxial cable of the short section is fixed at the tail of the sensor probe and is connected with the three coaxial cable of the long section through an SMA joint, so that the three coaxial cable can be applied to different capacitive sensor probes; the measurement is based on the flat plate capacitance principle, the core pole of the sensor probe constitutes one pole plate of the variable capacitor, the rotating blade constitutes the other pole plate of the variable capacitor, the tip clearance signal is obtained by measuring the capacitance change between the two pole plates, and the tip clearance signal obtained by the sensor probe is transmitted to the measuring system host through the three coaxial cable;

[0008] The signal demodulation module demodulates the tip clearance signal output by the capacitive sensor to convert the tip clearance signal into a voltage signal; the acquisition module acquires and preliminarily processes the voltage signal and transmits the data to the upper computer; the upper computer further processes the data to obtain the tip clearance value, and simultaneously stores and displays the data value;

[0009] The response bandwidth measuring device is replaced with the sensor probe and is connected with the three coaxial cable of the long section through the SMA joint;

[0010] The response bandwidth measuring device is composed of a sensitive pole plate, a receiving pole plate, a rotating table, a displacement table and a direct current blocking capacitor;

[0011] The rotating table comprises a rotating shaft, a mounting seat and a controller, the controller is used for controlling the rotating speed of the rotating shaft and displaying the current rotating speed in real time; a supporting rod is arranged on the mounting seat, the displacement table is movably sleeved on the supporting rod; the rotating shaft is rotatably arranged in the middle part of the mounting seat;

[0012] The sensitive pole plate is fixed on the rotating shaft as a rotating component and is composed of a PCB plate;

[0013] The receiving pole plate is fixedly installed on the displacement table and located above the sensitive pole plate and is composed of a PCB plate, the distance between the receiving pole plate and the sensitive pole plate is changed by adjusting the height of the displacement table;

[0014] The surfaces of the receiving pole plate and the sensitive pole plate opposite to each other are conductive layers paved with copper and respectively constitute receiving electrodes and sensitive electrodes, the rest are insulating layers, the sensitive pole plate is grounded, and the receiving pole plate is connected with the core pole of the long section of the three coaxial cable and the direct current blocking capacitor in turn;

[0015] The sensitive electrode forms one pole of the variable capacitor, and the receiving electrode forms the other pole of the variable capacitor. During the rotation of the sensitive plate, the facing area between the two electrodes changes, causing a capacitance change in the response bandwidth measuring device. The shapes of the sensitive electrode and the receiving electrode are designed so that the capacitance change between the plates is a standard sine signal.

[0016] Furthermore, an even number of sensitive electrodes are provided on the conductive layer of the sensitive plate. Let the inner diameter of the sensitive plate be R si , and the outer diameter be R so . R1 and R2 are the edges of the sensitive electrode. The part between R1 and R2 is the sensitive electrode, forming an even number of petal-like structures, and the rest is the insulating layer. R1 and R2 are represented by the polar coordinate equations:

[0017] R1 = R + τ[sin(Nφ) + 1]

[0018] R2 = R - τ[sin(Nφ) + 1]

[0019] Among them, R is the radius of the reference circle that can separate the two sine waves formed by R1 and R2; N is the number of petal-like structures of the sensitive electrode; τ is the amplitude of the sine signal superimposed on the reference circle; φ represents the rotation angle of the rotor relative to the stator, φ = ωt, and ω is the rotation angular velocity of the rotor;

[0020] To ensure the integrity of the sensitive plate, the inner diameter R of the sensitive plate si < R - 2τ, and the outer diameter R of the sensitive plate so > R + 2τ.

[0021] Furthermore, an even number of receiving electrodes are provided on the conductive layer of the receiving plate. Let the inner diameter of the receiving plate be R ri , and the outer diameter be R ro . The shape of the receiving electrode is a sector ring, the inner diameter of the sector ring is R3, the outer diameter is R4, and the central angle is λ;

[0022] To ensure the integrity of the receiving electrode, the inner diameter R of the receiving plate ri < R3, and the outer diameter R of the receiving plate ri > R4.

[0023] Furthermore, mechanical vibration and rotor tilt can cause a change Δd in the distance d between the sensitive plate and the receiving plate; an even number of receiving electrodes are designed to be evenly distributed on the conductive layer of the receiving plate, and each pair of receiving electrodes is diametrically opposite. Let the area of a single receiving electrode be S, then the capacitance C between each pair of receiving electrodes and the sensitive electrode is:

[0024]

[0025] Neglect (Δd) 2, the average effect of several receiving electrodes is used to reduce the error introduced by the change of the distance d between the sensitive electrode and the receiving electrode.

[0026] Further, to ensure the phase consistency of the signals received by several receiving electrodes, the number M of receiving electrodes is a divisor of the number N of sensitive electrodes.

[0027] Further, the central angle of the sector of each receiving electrode is The overlapping area between the receiving electrode and the sensitive electrode is calculated, and the sector area formula in polar coordinates is known as Where r(θ) is the radius of the sector, and θ is the central angle, then the overlapping area is:

[0028]

[0029] The overlapping area S between the electrodes is rs The capacitance value C between the receiving electrode and the sensitive electrode is calculated as:

[0030]

[0031] Where d is the distance between the sensitive electrode and the receiving electrode; φ represents the rotation angle of the rotor relative to the stator, φ = ωt, ω is the rotation angular velocity of the rotor; N is the number of sensitive electrode petal-shaped structures; R1 and R2 are the edges of the sensitive electrode; M is the number of receiving electrodes; τ is the amplitude of the sinusoidal signal superimposed on the reference circumference;

[0032] When the shapes of the receiving electrode and the sensitive electrode are determined, the DC part is isolated by the DC blocking capacitor C1, and the remaining part is a sinusoidal signal, and the signal amplitude is The frequency is

[0033] Before carrying out the response bandwidth measurement experiment, according to the frequency band range of the measured object, the number N of sensitive electrodes and the rotation angular velocity ω need to be determined.

[0034] Further, the upper surface of the displacement table is provided with a level, and the support rod includes a support rod A and a support rod B, to ensure that the displacement table remains horizontal, two methods are included:

[0035] One is that the support ring buckle movably mounted on the support rod A and the support rod B can move up and down; the displacement table is sleeved on the support rod A and the support rod B, and the displacement table is kept horizontal by adjusting the position of the support ring buckle and observing the level;

[0036] Another way, the support rod B can be up and down the active installation of support ring buckle, support ring buckle on the installation of the support plate, the displacement table one end of the support rod A, the other end of the support plate, by adjusting the support ring buckle position and observation level to keep the displacement table level.

[0037] Compared with the prior art, the technical scheme of the utility model brings the beneficial effects that:

[0038] 1. Improve the measurement accuracy: by designing a device capable of generating a standard capacitance signal, a capacitance signal with a sinusoidal signal trend change is generated to simulate the input of the capacitance tip clearance measurement system; avoid the error caused by ignoring the system capacitance-voltage conversion process when using standard voltage signal as input, thereby significantly improving the accuracy of system response bandwidth measurement.

[0039] 2. Enhance system adaptability: the utility model can adapt to the test requirements of different frequency ranges, and is suitable for various types of capacitive sensors; the generated capacitance signal with a sinusoidal signal trend change has adjustable frequency and amplitude, which can be changed according to user requirements and application scenarios; by generating standard capacitance signals of different frequencies to simulate system input, the overall measurement of system response bandwidth is realized, overcoming the limitations of existing methods.

[0040] 3. Simplify the test process: the utility model adopts a bipolar plate rotating structure, which generates standard capacitance signals through rotary motion, avoiding complex circuit design and debugging process, simplifying the design and use of the test device, and improving the test efficiency.

[0041] 4. Ensure stability in high temperature environment: the capacitive tip clearance measurement system has the characteristics of high temperature resistance and anti-gas corrosion, and the measurement device designed by the utility model also has these advantages, which can operate stably in high temperature environment and ensure the reliability of measurement results.

[0042] 5. Realize real-time online measurement: the measurement device of the utility model supports online real-time measurement, which can dynamically monitor the tip clearance during the operation of the rotating machinery, timely reflect the change of system response bandwidth, and help improve the safety and performance of the rotating machinery.

[0043] 6. Reduce cost: the device structure of the utility model is simple and easy to process, which can be produced by any printed circuit board manufacturer, with short processing cycle and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A schematic diagram of a capacitive tip clearance measurement system is shown.

[0045] Figure 2 A structure principle diagram of the response bandwidth measurement device in the utility model is shown.

[0046] Figure 3 The structure schematic view of the sensitive pole plate of the response bandwidth measuring device in the utility model is shown.

[0047] Figure 4 The structure schematic view of the receiving pole plate of the response bandwidth measuring device in the utility model is shown.

[0048] Figure 5 The pole plate spacing change diagram caused by mechanical vibration and rotor tilt is shown.

[0049] Figure 6 The bandwidth measurement scheme diagram of the tip clearance measurement system using the utility model is shown.

[0050] Figure 7 The tip clearance measurement system bandwidth measurement flow chart using the utility model is shown.

[0051] The drawing mark: 1-capacitance sensor, 11-sensor probe, 12-three coaxial cable, 13-SMA joint, 2-measurement system host, 21-signal demodulation module, 22-acquisition module, 3-upper computer, 4-sensitive pole plate, 5-receiving pole plate, 6-controller, 7-rotary shaft, 8-displacement table, 81-supporting rod A, 82-supporting rod B, 83-supporting ring buckle, 84-level gauge, 9-mounting base, 10-direct current isolation capacitor;41-sensitive electrode, 42-sensitive pole plate insulating layer, 51-receiving electrode, 52-receiving pole plate insulating layer. DETAILED DESCRIPTION

[0052] The utility model will be further explained in detail in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0053] The capacitance type tip clearance measurement system is mainly composed of capacitance sensor 1, signal demodulation module 21, acquisition module 22, measurement system host 2 and upper computer 3 and other parts, as shown in Figure 1 .

[0054] Capacitance sensor 1 is composed of sensor probe 11 and three coaxial cable 12, and three coaxial cable 12 includes two long and short sections, and the short section of three coaxial cable is fixed at the tail of sensor probe and is connected with the long section of three coaxial cable through SMA joint, so as to apply three coaxial cable to different capacitance sensor probes 11;The measurement is based on the principle of flat plate capacitance, the sensor core pole constitutes one pole plate of variable capacitance, and the rotating blade constitutes another pole plate of variable capacitance, and the tip clearance value is obtained by measuring the capacitance change between the two pole plates. The tip clearance signal obtained by sensor probe 11 is transmitted to the measurement system host through low-noise three coaxial cable 12.

[0055] The signal demodulation module 21 in the measurement system host 2 demodulates the varying capacitance signal output by the capacitive sensor 1, converts the capacitance signal into a voltage signal; the data acquisition module 22 performs data acquisition and preliminary processing on the voltage signal, and transmits the data to the upper computer 3; the upper computer 3 further processes the data, calculates the blade tip clearance value, and simultaneously performs data storage and numerical display.

[0056] The response bandwidth measuring device is replaced with the sensor probe 11 and is connected with the long three-coaxial cable through the SMA joint; the response bandwidth measuring device of the capacitive blade tip clearance measurement system in the embodiment is composed of the sensitive electrode plate 4, the receiving electrode plate 5, the rotating table, the displacement table 8, the direct-current blocking capacitor 10 and the like, and the structure principle of the device is shown in Figure 2 .

[0057] The rotating table includes the rotating shaft 7, the mounting seat 9 and the controller 6, the controller 6 is used for controlling the rotating speed of the rotating shaft 7 and displaying the current rotating speed in real time; in the embodiment, the mounting seat 9 is provided with a support rod A81, and one end of the displacement table 8 is movably sleeved on the support rod A81; in order to ensure the level of the receiving electrode plate 5 installed on the displacement table 8, a support rod B82 is further arranged on the mounting seat 9, a supporting plate is installed on the support rod B82, and the other end of the displacement table 8 is placed on the supporting plate, and the level of the receiving electrode plate 5 is adjusted by observing the level meter 84; the rotating shaft 7 is rotatably arranged in the middle of the mounting seat 9;

[0058] The sensitive electrode plate 4 is fixed to the rotating shaft 7 as a rotating component and is composed of a printed circuit board (PCB) plate;

[0059] The receiving electrode plate 5 is installed and fixed on the displacement table 8 and located above the sensitive electrode plate 4, is composed of a printed circuit board (PCB) plate, and the distance between the receiving electrode plate 5 and the sensitive electrode plate 4 is changed by adjusting the height of the displacement table 8;

[0060] The surfaces of the receiving electrode plate 5 and the sensitive electrode plate 4 opposite to each other are conductive layers paved with copper and respectively constitute receiving electrodes and sensitive electrodes, the rest are insulating layers, the sensitive electrode plate 4 is grounded, and the receiving electrode plate 5 is connected with the core of the direct-current blocking capacitor 10 and the three-coaxial cable 12 in sequence.

[0061] The sensitive electrode 41 in the response bandwidth measuring device constitutes one pole of the variable capacitor, the receiving electrode 51 constitutes the other pole of the variable capacitor, the facing area between the two electrodes changes in the rotating process of the sensitive electrode plate, thereby causing the capacitance change of the response bandwidth measuring device, and the shapes of the sensitive electrode 41 and the receiving electrode 51 are designed to make the capacitance change between the electrode plates a standard sine signal.

[0062] The inner diameter of the sensitive electrode plate 4 is designed as R si , the outer diameter is R so , the petal shape of the sensitive electrode 41 is as shown inFigure 3 As shown, R1 and R2 are the edges of the sensitive electrode plate. The part between R1 and R2 on the conductive layer is the sensitive electrode, forming an even number of petal-shaped structures, and the rest is the insulating layer. R1 and R2 are represented by the polar coordinate equation as:

[0063] R1 = R + τ[sin(Nφ) + 1]

[0064] R2 = R - τ[sin(Nφ) + 1]

[0065] Where, R is the radius of the reference circle that can separate the two sine waves formed by R1 and R2; N is the number of petal-shaped structures of the sensitive electrode; τ is the amplitude of the sine signal superimposed on the reference circle; φ represents the rotation angle of the rotor relative to the stator, φ = ωt, and ω is the rotational angular velocity of the rotor. To ensure the integrity of the sensitive electrode plate 4, the inner diameter R of the sensitive electrode plate 4 si < R - 2τ, and the outer diameter R of the sensitive electrode plate 4 si > R + 2τ.

[0066] The inner diameter of the receiving electrode plate 5 is designed to be R ri , and the outer diameter is Rr o . The shape of the receiving electrode 51 is as Figure 4 shown. The receiving electrode plate 5 is in the shape of a sector ring, with the inner diameter of the sector ring being R3, the outer diameter being R4, and the central angle being λ. To ensure the integrity of the receiving electrode plate 5, the inner diameter R of the receiving electrode plate 5 ri < R3, and the outer diameter R of the receiving electrode plate 5 ri > R4.

[0067] Preferably, mechanical vibration and rotor tilt may cause a change Δd in the distance d between the sensitive electrode plate 4 and the receiving electrode plate 5, as Figure 5 shown. An even number of receiving electrodes 51 are designed to be evenly distributed on the conductive layer of the receiving electrode plate 5. Each pair of receiving electrodes 51 is diametrically opposite. Taking Figure 4 as an example, the number of receiving electrodes 51 is 4. Let the area of a single receiving electrode 51 be S, then the capacitance C between each pair of receiving electrodes 51 and the sensitive electrode 41 is:

[0068]

[0069] Since Δd is an infinitesimal quantity, (Δd) 2 is a second-order infinitesimal quantity and can be ignored. Therefore, the average effect of multiple receiving electrodes 51 can be utilized to reduce the error introduced by the change in d.

[0070] Preferably, to ensure that the signals received by multiple receiving electrodes 51 have the same phase, the number M of receiving electrodes 51 is a divisor of the number N of sensitive electrodes 41 in the shape of a petal.

[0071] Since the integral value of the periodic function in a period is constant, in order to avoid the output capacitor constant, the sector center angle of each receiving electrode 51

[0072] The overlapping area between the receiving electrode 51 and the sensitive electrode 41 is calculated, and the area formula in polar coordinates is known Therefore, the overlapping area is:

[0073]

[0074] The overlapping area S between the receiving electrode 51 and the sensitive electrode 41 is calculated rs The capacitance value C between the receiving electrode 51 and the sensitive electrode 41 can be calculated as:

[0075]

[0076] Where d is the distance between the sensitive electrode and the receiving electrode; φ represents the rotation angle of the rotor relative to the stator, φ = ωt, ω is the rotation angular velocity of the rotor; N is the number of sensitive electrode petal-shaped structures; R1 and R2 are the edges of the sensitive electrode; M is the number of receiving electrodes; τ is the amplitude of the sine signal superimposed on the reference circumference;

[0077] When the shapes of the receiving electrode 51 and the sensitive electrode 41 are determined, the direct current part is isolated by the blocking capacitor C1, and the remaining part is a sine signal, and the signal amplitude is The frequency is

[0078] Before carrying out the response bandwidth measurement experiment, according to the frequency band range of the measured object, the number N of the sensitive electrode 41 and the rotation angular velocity ω are determined.

[0079] The response bandwidth measurement device of the utility model is used for measuring the bandwidth of the capacitive tip clearance measurement system, and the system bandwidth measurement scheme is as shown in Figure 6 The response bandwidth measurement device based on the double-plate rotating structure can generate varying capacitance test signals of different frequencies, and the output voltage signals are transmitted to the signal demodulation module through the three coaxial cables, the output voltage signals are collected and stored, the amplitudes of the output signals under different frequencies are compared, and the bandwidth of the tip clearance measurement system is obtained.

[0080] The capacitive tip clearance measurement system bandwidth measurement test process is as shown in Figure 7The installation and debugging of the experimental equipment to be tested are completed, the frequency points to be tested have n, the control signal frequency of the response bandwidth measuring device based on the rotating structure of the bipolar plate is adjusted, the output voltage of the signal demodulation module under different test frequencies is recorded, the output signal amplitude is compared, when the output signal amplitude is reduced to 0.707 times of the maximum amplitude, the upper limit value minus the lower limit value of the frequency obtained is the bandwidth of the tip clearance measurement system. If the signal amplitude output by the experimental equipment to be tested meets the requirements, the bandwidth of the experimental equipment to be tested is the selected working frequency band range, if the amplitude does not meet the requirements, the bandwidth of the experimental equipment to be tested is less than the working frequency band range, and the experimental equipment to be tested does not meet the requirements.

[0081] The utility model is not limited to the above-mentioned embodiments. The above description of the specific embodiments is intended to describe and illustrate the technical scheme of the utility model, and the above-mentioned specific embodiments are only illustrative and not restrictive. Without departing from the purpose of the utility model and the scope of protection of the claims, those skilled in the art can make many forms of specific changes under the inspiration of the utility model, and these all belong to the protection scope of the utility model.

Claims

1. A response bandwidth measuring device of a capacitive tip clearance measurement system based on a bipolar plate rotating structure, the capacitive tip clearance measurement system being composed of a capacitive sensor, a measurement system host and an upper computer connected in sequence, the measurement system host comprising a signal demodulation module and an acquisition module, the capacitive sensor being composed of a sensor probe and a three coaxial cable connected with each other, the three coaxial cable comprising a long section and a short section, the three coaxial cable of the short section being fixed at the tail of the sensor probe and connected with the three coaxial cable of the long section through an SMA joint, so as to apply the three coaxial cable to different capacitive sensor probes; the measurement is based on a flat plate capacitance principle, a core pole of the sensor probe constitutes one pole plate of a variable capacitor, a rotating blade constitutes another pole plate of the variable capacitor, a tip clearance signal is obtained by measuring the capacitance change between the two pole plates, the tip clearance signal obtained by the sensor probe is transmitted to the measurement system host through the three coaxial cable; the signal demodulation module demodulates the tip clearance signal output by the capacitive sensor, and converts the tip clearance signal into a voltage signal; the acquisition module acquires and preliminarily processes the voltage signal, and transmits the data to the upper computer; the upper computer further processes the data to obtain a tip clearance value, and simultaneously stores and displays the data; characterized in that, the response bandwidth measuring device is used to replace the sensor probe and is connected with the three coaxial cable of the long section through the SMA joint; the response bandwidth measuring device is composed of a sensitive pole plate, a receiving pole plate, a rotating table, a displacement table and a direct current blocking capacitor; the rotating table comprises a rotating shaft, a mounting seat and a controller, the controller is used for controlling the rotating speed of the rotating shaft and displaying the current rotating speed in real time; a support rod is arranged on the mounting seat, the displacement table is movably sleeved on the support rod; the rotating shaft is rotatably arranged in the middle part of the mounting seat; the sensitive pole plate is fixed on the rotating shaft as a rotating component and is composed of a PCB plate; the receiving pole plate is fixedly installed on the displacement table and located above the sensitive pole plate, and is composed of a PCB plate; the distance between the receiving pole plate and the sensitive pole plate is changed by adjusting the height of the displacement table; the surfaces of the receiving pole plate and the sensitive pole plate opposite to each other are conductive layers paved with copper and respectively constitute receiving electrodes and sensitive electrodes, and the rest are insulating layers; the sensitive pole plate is grounded, and the receiving pole plate is connected with the core pole of the long section of the three coaxial cable and the direct current blocking capacitor in sequence; the sensitive electrode constitutes one pole of a variable capacitor, and the receiving electrode constitutes another pole of the variable capacitor; the facing area between the two electrodes changes during the rotation of the sensitive pole plate, causing the capacitance change of the response bandwidth measuring device; the shapes of the sensitive electrode and the receiving electrode are designed to make the capacitance change between the pole plates a standard sinusoidal signal.

2. The response bandwidth measuring device of the capacitive tip clearance measurement system based on the rotating structure of the bipolar plate according to claim 1, characterized in that, The conductive layer of the sensitive electrode plate is provided with an even number of sensitive electrodes, the inner diameter of the sensitive electrode plate is R si , the outer diameter is R so , R1 and R2 are the edges of the sensitive electrode, the part between R1 and R2 is the sensitive electrode, an even number of petal-shaped structures are formed, the remaining part is an insulating layer, and R1 and R2 are represented by a polar equation. R1=R+τ[sin(Nφ)+1] R2=R-τ[sin(Nφ)+1] wherein, R is the radius of a reference circumference capable of separating the two sinusoidal waves constituted by R1 and R2; N is the number of petal-shaped structures of the sensitive electrode; τ is the amplitude of the sinusoidal signal superimposed on the reference circumference; φ represents the rotation angle of the rotor relative to the stator, φ=ωt, and ω is the rotation angular velocity of the rotor. To ensure the integrity of the sensitive electrode plate, the inner diameter R si <R - 2τ, the outer diameter R so > R + 2τ of the sensitive electrode plate.

3. The response bandwidth measuring device of the capacitive tip clearance measurement system based on the rotating structure of the bipolar plate according to claim 1, characterized in that, An even number of receiving electrodes are provided on the conductive layer of the receiving plate, and the inner diameter of the receiving plate is R. ri The outer diameter is R ro The receiving electrode is shaped like a fan ring, with an inner diameter of R3, an outer diameter of R4, and a central angle of λ. To ensure the integrity of the receiving electrode, the inner diameter R ri R3, the outer diameter R ri R4 of the receiving electrode plate 4. The response bandwidth measuring device of the capacitive tip clearance measurement system based on the rotating structure of the bipolar plate according to claim 1, characterized in that, The mechanical vibration and the rotor tilt can cause the distance d between the sensitive electrode plate and the receiving electrode plate to change by Δd; an even number of receiving electrodes are designed to be evenly distributed on the conductive layer of the receiving electrode plate, each pair of receiving electrodes is diametrically opposite, the area of a single receiving electrode is S, and the capacitance C between each pair of receiving electrodes and the sensitive electrode is: Neglect (Ad) 2 The variation of the distance d between the sensitive and the receiving plate introduces an error which is reduced by the averaging effect of several receiving electrodes.

5. The response bandwidth measuring device of the capacitive tip clearance measurement system based on the rotating structure of the bipolar plate according to claim 1, characterized in that, To ensure that the phases of the signals received by the receiving electrodes are consistent, the number M of receiving electrodes is a divisor of the number N of sensitive electrodes.

6. The response bandwidth measuring device of the capacitive tip clearance measurement system based on the rotating structure of the bipolar plate according to claim 1, characterized in that, central angle of the sector circle of each receiving electrode The overlapping area between the receiving electrode and the sensitive electrode is calculated, and the sector area formula under the polar coordinate is known as Where r(θ) is the sector radius, and is the central angle of θ, and the overlapping area is: The overlapping area S between the electrode plates rs The capacitance value C between the receiving electrode and the sensitive electrode is calculated as Wherein, d is the distance between the sensitive electrode plate and the receiving electrode plate; φ represents the rotation angle of the rotor relative to the stator, φ = ωt, ω is the rotation angular velocity of the rotor; N is the number of sensitive electrode petal-shaped structures; R1 and R2 are the edges of the sensitive electrode plate; M is the number of receiving electrodes; τ is the amplitude of the sinusoidal signal superimposed on the reference circumference; When the shape of the receiving electrode and the sensitive electrode is determined, the direct current part is isolated by the direct current isolation capacitor C1, and the remaining part is a sinusoidal signal, and the signal amplitude is The frequency is Before carrying out the response bandwidth measurement experiment, according to the frequency band range of the measured object, the number N of sensitive electrodes and the rotation angular velocity ω need to be determined.

7. The response bandwidth measuring device of the capacitive tip clearance measurement system based on the rotating structure of the bipolar plate according to claim 1, characterized in that, The upper surface of the displacement table is provided with a level meter, and the support rods include support rod A and support rod B, in order to ensure that the displacement table remains horizontal, two modes are included: One is that the support ring buckle movably mounted on the support rod A and the support rod B; the displacement table is sleeved on the support rod A and the support rod B, and the displacement table remains horizontal by adjusting the position of the support ring buckle and observing the level meter; Another way is that the support ring buckle movably mounted on the support rod B is movably mounted on the support rod B, and the support ring buckle is movably mounted on the support rod B; one end of the displacement table is sleeved on the support rod A, and the other end is placed on the support plate, and the displacement table remains horizontal by adjusting the position of the support ring buckle and observing the level meter.

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