Cycle life test method for deep cryogenic tip clearance sensor

Abstract

The invention discloses a cycle life test method for a deep cryogenic blade tip clearance sensor, comprising the following steps: step 1: sealing and independently packaging a simulated blade (6), a first temperature sensor (7) and a deep cryogenic blade tip clearance sensor (8) in a deep cryogenic box (1); step 2: setting temperature change process parameters of the cycle life test through a temperature control component, and calculating a low temperature holding time H according to the temperature change process parameters. dhold And high temperature holding time H uhold ; Step 3: The temperature control component realizes the cyclic heating and cooling in the deep cold box (1); Step 4: During the heating and cooling cycle in the deep cold box (1), the temperature control component collects data in real time. The present invention can effectively control the heating and cooling speed of the deep low temperature blade tip clearance sensor test environment, truly simulate the working environment of the deep low temperature blade tip clearance sensor, and ensure the effectiveness and accuracy of the performance verification results of the deep low temperature blade tip clearance sensor.

Description

Technical Field

[0001] The invention relates to a detection method for a rotating mechanical component, in particular to a cycle life test method for a deep low temperature blade tip clearance sensor. Background Art

[0002] In rotating machinery such as aircraft engines, gas turbines, steam turbines, and compressors, the tiny distance between the top of the rotor blade and the inner wall of the casing is called the tip clearance, and the tip clearance is one of the important parameters that affect the performance of rotating machinery. A smaller tip clearance can reduce gas leakage at the tip and significantly improve the operating efficiency of rotating machinery, but a tip clearance that is too small will cause friction between the blade and the casing, seriously endangering the safe operation of the rotating machinery. There are many factors that affect the tip clearance of rotating machinery, among which the temperature change of components such as rotor blades and casings is an important factor affecting the tip clearance value. The temperature change caused by the changing working conditions causes the blades and casings to expand and contract, which directly leads to changes in the tip clearance. Therefore, real-time online monitoring of the tip clearance is of great significance to improving the performance of rotating machinery and ensuring the safe operation of rotating machinery.

[0003] The application environment of rotating machinery is complex and diverse. The real-time online monitoring of the tip clearance used in cryogenic nitrogen compressors (ambient temperature range can reach 25℃~-196℃) includes the deep cryogenic operation performance of the blades and the deep cryogenic cycle life of the blades. When the cryogenic nitrogen compressor is not working, its temperature is room temperature (about 25℃); when the cryogenic nitrogen compressor starts working, its temperature will slowly drop to -196℃, which is the critical temperature for nitrogen to be converted into liquid nitrogen; and when the cryogenic nitrogen compressor stops working again, its temperature will slowly rise to room temperature. The large-scale temperature change caused by each start and stop of the cryogenic nitrogen compressor places extremely high demands on the temperature adaptability of the tip clearance measurement system. In order to ensure that the tip clearance sensor can work normally for a long time under the harsh conditions of a large range of temperature changes, it is necessary to verify the cycle life of the tip clearance sensor within the working temperature change range. At present, the test scheme for realizing cyclic temperature change in the temperature range from room temperature to -196℃ is mainly as follows: immerse the tip clearance sensor directly from room temperature into a liquid nitrogen environment, take it out after the tip clearance sensor temperature drops to -196℃, then place it in a room temperature environment and heat it to room temperature, thus completing a temperature change process. However, the heating and cooling rates of this test scheme are too fast, which is different from the temperature change state of the tip clearance sensor during actual operation, and the tip clearance sensor works in a gas environment, not a liquid nitrogen environment. Therefore, the simulated environment of the deep low temperature cycle life test scheme of the tip clearance sensor in the prior art does not match the actual environment, resulting in a large error in the test results. Summary of the invention

[0004] The purpose of the present invention is to provide a cycle life test method for a deep cryogenic tip clearance sensor, which can effectively control the heating and cooling rates of the deep cryogenic tip clearance sensor test environment, truly simulate the working environment of the deep cryogenic tip clearance sensor, and ensure the effectiveness and accuracy of the performance verification results of the deep cryogenic tip clearance sensor.

[0005] The present invention is achieved in that:

[0006] A cycle life test method for a deep cryogenic blade tip clearance sensor, the cycle life test method is implemented by a cycle life test device for the deep cryogenic blade tip clearance sensor, the cycle life test device comprising a deep cryogenic box, a simulated blade, a first temperature sensor, a deep cryogenic blade tip clearance sensor and a temperature control component;

[0007] The cycle life test method of the deep cryogenic blade tip clearance sensor comprises the following steps:

[0008] Step 1: sealing and independently packaging the simulated blade, the first temperature sensor and the deep low temperature blade tip clearance sensor in a deep cold box;

[0009] Step 2: Set the temperature change process parameters of the cycle life test through the temperature control component, and calculate the low temperature holding time H according to the temperature change process parameters dhold And high temperature holding time H uhold ;

[0010] Step 3: The temperature control component realizes the cycle heating and cooling in the deep cold box;

[0011] Step 4: During the heating and cooling cycle in the cryogenic box, the temperature control component collects data in real time.

[0012] The step 1 comprises the following sub-steps:

[0013] Step 1.1: Determine whether the temperature range and sealing performance of the cycle life test chamber meet the test requirements. If so, proceed to step 1.2. If not, replace the cycle life test chamber that meets the test requirements.

[0014] Step 1.2: Sealing and encapsulating the simulated blade, the first temperature sensor, and the deep low temperature blade tip clearance sensor in a sealing member;

[0015] Step 1.3: Install the seal in the cryogenic box;

[0016] Step 1.4: Lead the cables of the first temperature sensor and the deep cryogenic tip clearance sensor out of the seal and the deep cryogenic box;

[0017] Step 1.5: Connect the deep cryogenic tip clearance sensor and the first temperature sensor to the temperature control assembly;

[0018] Step 1.6: Isolate the interior of the cryogenic freezer from the outside world.

[0019] The requirement for the temperature range of the cycle life test chamber is: the minimum test temperature of the deep low temperature blade tip clearance sensor in the cycle life test is T min , the maximum test temperature is T max , then the real-time temperature T in the deep freezer satisfies T min ≤T≤T max .

[0020] The sealing performance requirement of the cycle life test chamber is: when the temperature in the cryogenic box reaches the minimum test temperature, the heat Q" transferred from the cryogenic box to the seal is equal to the maximum heat q transferred from the cable lead-out part to the outside world. max Q”>q max ; The heat Q transferred from the cryogenic box to the seal includes the cooling heat Q transferred from the cryogenic box to the seal during the cooling stage 1 The heat Q transferred from the cryogenic box to the seal during the heating stage 2 ;

[0021] The cooling heat Q transferred from the deep freezer to the seal during the cooling stage 1 The calculation formula is:

[0022]

[0023] Among them, k 1 The box cooling heat Q' is used for the cooling coefficient of the seal, k 1 is a constant and k 1 ≥1; S 1 is the outer surface area of ​​the seal, S is the inner surface area of ​​the cryogenic box;

[0024] Q' is the box cooling heat required for the temperature drop in the deep cold box test chamber. The calculation formula of Q' is:

[0025]

[0026] Among them, U is the cooling rate, ρ is the density of nitrogen, C p is the specific heat capacity of nitrogen, d is the inner diameter of the cryogenic box, l is the inner wall height of the cryogenic box;

[0027] The heating heat Q transferred from the cryogenic box to the seal during the heating stage 2 The calculation formula is:

[0028]

[0029] Among them, k 2 The heat required for the temperature rise in the cryogenic chamber test chamber W' is used for the temperature rise coefficient of the seal, k2 is a constant and k 2 ≥1;

[0030] W' is the heat required to heat up the deep cold box test chamber. The calculation formula of W' is:

[0031]

[0032] Where, U' is the heating rate;

[0033] The calculation formula for the heat q transferred from the cable lead-out portion to the outside is:

[0034]

[0035] Where, λ is the thermal conductivity of the cable, D is the diameter of the cable, T is the real-time temperature in the deep freezer, and T 3 is the external environment temperature of the deep freezer;

[0036] When the real-time temperature T in the deep freezer drops to the cooling termination temperature T 2 When the cable leads to the outside, the heat transferred to the outside reaches the maximum value q max .

[0037] In step 2, the temperature change process parameters include: the cooling starting temperature T 1 , cooling end temperature T 2 , cooling time H d , cooling speed U, heating starting temperature T 1 '、Heating end temperature T 2 '、Heating time H u , heating rate U' and heating and cooling repetition times s;

[0038] The cooling time H d The calculation formula is:

[0039]

[0040] The heating time H u The calculation formula is:

[0041]

[0042] In the cooling stage, the low temperature holding time H dhold The calculation method is:

[0043] Step S1-1: Cooling from the starting temperature T in the deep freezer 1 Drop to the cooling end temperature T 2 Calculate the ideal cooling temperature T of the seal when 4 , the calculation formula is:

[0044]

[0045] Among them, C ps is the specific heat capacity of the seal, ρ s is the density of the seal;

[0046] Step S1-2: using a lumped parameter method to represent the temperature change process of the seal;

[0047] The lumped parameter method formula for the temperature change process of the seal is:

[0048]

[0049] Among them, λ 1 is the thermal conductivity of the seal, S 1 is the outer surface area of ​​the seal, V 1 is the volume of the seal, τ is the temperature of the seal from t 1 Change to t 2 The time required; t 1 The temperature T in the deep freezer is the starting temperature of the cooling 1 Drop to the cooling end temperature T 2 The ideal cooling temperature of the seal at t 2 It is the cooling test temperature of the deep low temperature blade tip clearance sensor;

[0050] Step S1-3: When t 2 =T min When t 1 Change to t 2 The required time τ is the low temperature holding time H dhold ;

[0051] In the heating stage, the high temperature holding time H uhold The calculation method is:

[0052] Step S2-1: In the cryogenic box, the temperature is raised from the starting temperature T 1 'Raise to the heating end temperature T 2 ', calculate the ideal heating temperature T of the seal 5 , the calculation formula is:

[0053]

[0054] Step S2-2: using a lumped parameter method to represent the temperature change process of the seal;

[0055] The lumped parameter method formula for the temperature change process of the seal is:

[0056]

[0057] Where τ' is the temperature of the seal from t 1 'Change to t 2 'The time required, t 1 ' is the temperature T from the start of heating in the deep cold box 1 'Raise to the heating end temperature T 2 The ideal heating temperature of the seal at ', t 2 ' is the heating test temperature of the deep low temperature blade tip clearance sensor;

[0058] Step S2-3: When t 2 '=T max When t 1 'Change to t 2 'The required time τ', which is the holding time H at high temperature uhold .

[0059] In the step 3, the temperature control component includes a data acquisition device, a computer, a temperature controller and a second temperature sensor; the cycle life test device also includes a nitrogen tank, a solenoid valve, a heater and a temperature drop gas supply pipeline, the nitrogen tank has -196°C nitrogen built in, the nitrogen tank is connected to the cycle life test chamber through the temperature drop gas supply pipeline, the solenoid valve is arranged on the temperature drop gas supply pipeline and is electrically connected to the temperature control component; the heater is electrically connected to the temperature control component, and the heating coil of the heater is arranged inside the cycle life test chamber;

[0060] When the temperature is lowered in the cryogenic box, step 3 further comprises the following sub-steps:

[0061] Step 3.1.1: The computer calculates the cooling heat Q required to achieve the cooling rate U in the deep freezer, and sets the ideal cooling curve according to the cooling rate U. The calculation formula for the cooling heat Q is as follows:

[0062]

[0063] Where d is the inner diameter of the cryogenic box, l is the inner wall height of the cryogenic box, L is the wall thickness of the cryogenic box; T is the real-time temperature in the cryogenic box, T 3 is the external environment temperature of the cryogenic box; Q' is the heat required for cooling the cryogenic box test chamber, ρ is the density of nitrogen, C p is the specific heat capacity of nitrogen, λ b is the thermal conductivity of the cryogenic box wall, △Q is the heat consumed by the heat exchange between the cryogenic box and the external environment;

[0064] Step 3.1.2: The temperature controller opens the solenoid valve to allow the -196°C low-temperature nitrogen in the nitrogen tank to enter the cryogenic box through the temperature-reducing gas supply pipeline, thereby reducing the temperature in the cryogenic box;

[0065] Step 3.1.3: The real-time temperature T in the cryogenic box is collected by a second temperature sensor disposed in the cryogenic box, and is sent to a computer through a temperature controller. The computer generates an actual cooling curve according to the real-time temperature T;

[0066] Step 3.1.4: Compare the ideal cooling curve with the actual cooling curve, and calculate the real-time cooling temperature T of the seal at the end of the cooling stage of the deep cold box 4 ' and the ideal cooling temperature T 4 The difference between the two values ​​is used to calculate the remaining opening time of the solenoid valve. The calculation formula is:

[0067]

[0068] Among them, τ d The seal is cooled down by the real-time temperature T 4 'Cool down to the ideal cooling temperature T 4 the time required;

[0069] Step 3.1.5: Correct the low temperature holding time H of the deep freezer dhold , low temperature insulation correction time H dhold1 For: H dhold1 =H dhold +τ d Formula (9);

[0070] Step 3.1.6: When the temperature in the deep freezer drops to the cooling end temperature T 2 After that, the temperature controller controls the solenoid valve to close, and the cryogenic box is at the cooling end temperature T 2 Insulation, the insulation time is the insulation time at low temperature H dhold1 ;

[0071] Step 3.1.7: After the low-temperature insulation is completed, the temperature inside the deep freezer is increased.

[0072] In step 3.1.4, the temperature range of the cryogenic box is T 2 +30 <T<T 1 -30, and the actual cooling rate U d When <0.8U, it is considered that the cryogenic box may be leaking and needs to be repaired.

[0073] When the temperature in the cryogenic box 1 is increased, step 3 further comprises the following sub-steps:

[0074] Step S3.2.1: The computer calculates the heating amount W required to achieve the heating rate U' in the cryogenic box, the heating amount W is equal to the heat W' required to heat the cryogenic box test chamber, and sets the ideal heating curve according to the heating rate U';

[0075] Step 3.2.2: The temperature controller turns on the heater to increase the temperature inside the cryogenic box;

[0076] Step 3.2.3: The real-time temperature T in the cryogenic box is collected by a second temperature sensor disposed in the cryogenic box, and is sent to a computer through a temperature controller. The computer generates an actual temperature rise curve according to the real-time temperature T;

[0077] Step 3.2.4: Compare the ideal heating curve with the actual heating curve and calculate the real-time heating temperature T of the seal at the end of the deep cold box heating stage 5 ' and the ideal heating temperature T 5 The difference between the two values ​​is used to calculate the remaining opening time of the heater. The calculation formula is:

[0078]

[0079] Among them, τ u The seal is heated from real-time temperature T 5 'Heating to the ideal heating temperature T 5 the time required;

[0080] Step 3.2.5: Correct the holding time H at high temperature in the deep freezer uhold , high temperature insulation correction time H uhold1 For: H uhold1 =H uhold +τ u Formula (9-1);

[0081] Step 3.2.6: When the temperature in the deep freezer reaches the heating end temperature T 2 'After that, the temperature controller 13 controls the heater to turn off, and the cryogenic box is at the heating end temperature T 2 'Insulation, high temperature insulation time length is low temperature insulation time H uhold1 ;

[0082] Step 3.2.7: After the high temperature insulation is completed, the temperature in the deep freezer is lowered.

[0083] In step 3.2.4, the temperature range of the cryogenic box is T 1 '+30 <T<T 2 '-30, and the actual heating rate U u <0.8U', the cryogenic box may be leaking and needs to be repaired.

[0084] Compared with the prior art, the present invention has the following beneficial effects:

[0085] 1. The present invention adopts a heater to heat the box body and -196°C liquid nitrogen to cool the box body, so there is no need to immerse the deep cryogenic tip clearance sensor in liquid nitrogen, which is more convenient to operate and can truly simulate the application environment of the deep cryogenic tip clearance sensor, thereby improving the reliability of the low temperature cycle life test of the deep cryogenic tip clearance sensor and meeting the requirements of the low temperature cycle life test of the deep cryogenic tip clearance sensor.

[0086] 2. The present invention collects and monitors the temperature inside the box in real time during the heating and cooling process, and adjusts the heating and cooling process and the subsequent insulation process according to the actual heating and cooling status, so that the heating and cooling speed in the box is safe, controllable and accurate, further improving the reliability of the low-temperature cycle life test of the deep low-temperature tip clearance sensor.

[0087] 3. The present invention solves the problem that the low-temperature cycle life of the deep-cryogenic tip clearance sensor cannot be effectively verified before being applied in industrial sites, provides effective data support for subsequent field applications, and can be applied to low-temperature cycle life test verification of various types of sensors.

[0088] The present invention can effectively control the heating and cooling rates of the deep cryogenic tip clearance sensor test environment, realize the real simulation of the deep cryogenic tip clearance sensor working environment through the cyclic control of the heating and cooling process, and can timely and effectively intervene in the test process according to the difference between the actual temperature change state and the ideal temperature change state during the test, thereby ensuring the validity and accuracy of the performance verification results of the deep cryogenic tip clearance sensor, and also providing a reliable basis for subsequent field applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 It is a working principle diagram of a cycle life test device used in the cycle life test method of the deep low temperature blade tip clearance sensor of the present invention;

[0090] Figure 2 yes Figure 1 A three-dimensional view of the middle support frame;

[0091] Figure 3 yes Figure 1 A cross-sectional view of the middle cable holder;

[0092] Figure 4 The present invention is a flow chart of a cycle life test method for a deep cryogenic blade tip clearance sensor.

[0093] In the figure, 1 is a deep cold box, 2 is an insulation layer, 3 is an exhaust hole, 4 is a top cover, 5 is a sealing member, 6 is a simulated blade, 7 is a first temperature sensor, 8 is a deep low temperature blade tip clearance sensor, 9 is a cable holder, 10 is a data collector, 11 is a sensor drive conditioning module, 12 is a computer, 13 is a temperature controller, 14 is a temperature display, 15 is a nitrogen tank, 16 is an electromagnetic valve, 17 is a heater, 18 is a second temperature sensor, 19 is a temperature drop air supply pipeline, 20 is a support frame, and 21 is a through hole. DETAILED DESCRIPTION

[0094] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0095] Please see attached Figure 1 The cycle life test method of the deep cryogenic blade tip clearance sensor of the present invention is implemented by a cycle life test device of the deep cryogenic blade tip clearance sensor, which comprises: a cycle life test box, a seal 5, a deep cryogenic blade tip clearance sensor 8, a temperature control component, a sensor drive conditioning module 11, a nitrogen tank 15, an electromagnetic valve 16, a heater 17 and a temperature drop air supply pipeline 19; the deep cryogenic blade tip clearance sensor 8 is sealed and packaged in the seal 5, and the seal 5 is arranged in the cycle life test box, and the cable of the deep cryogenic blade tip clearance sensor 8 is led out of the seal 5 and the cycle life test box and is electrically connected to the sensor drive conditioning module 11, and the sensor drive conditioning module 11 is electrically connected to the temperature control component; the nitrogen tank 15 has -196°C nitrogen built in, and the nitrogen tank 15 is connected to the cycle life test box through the temperature drop air supply pipeline 19, and the electromagnetic valve 16 is arranged on the temperature drop air supply pipeline 19 and is electrically connected to the temperature control component; the heater 17 is electrically connected to the temperature control component, and the heating coil of the heater 17 is arranged inside the cycle life test box. Since the cycle life test chamber is not a sealed chamber, there is air in the cycle life test chamber. When the temperature changes, the air may condense into ice or produce water vapor. The seal 5 can be used to prevent ice from forming on the surface of the deep low temperature blade tip clearance sensor 8 and affecting the normal operation of the deep low temperature blade tip clearance sensor 8.

[0096] The cycle life test chamber comprises a cryogenic box 1, an insulation layer 2 and a top cover 4; the cryogenic box 1 is a box structure with an opening at the top, the insulation layer 2 is arranged on the inner wall of the cryogenic box 1, and the top cover 4 is sealed and connected to the top opening of the cryogenic box 1. The insulation layer 2 and the top cover 4 ensure that the space inside the cryogenic box 1 is an independent space relative to the outside world, thereby meeting the large temperature change requirement of 25°C to -196°C.

[0097] The cryogenic box 1 is provided with an exhaust hole 3, which is respectively located on the two side end faces of the cryogenic box 1, and the electromagnetic valve 16 and the heater 17. When the temperature changes, the pressure state in the cryogenic box 1 may change. In order to ensure the test safety of the cryogenic box 1, the pressure can be appropriately released through the exhaust hole 3 when the pressure is too high. The exhaust hole 3, the electromagnetic valve 16 and the heater 17 are respectively arranged on both sides of the cryogenic box 1 to reduce the influence of the exhaust process on the temperature rise or fall.

[0098] Please see attached Figure 3 The top of the cryogenic box 1 is provided with a cable holder 9, which is in an "Ω" shape, so that the arc structure in the middle of the cable holder 9 can match and fit on the surface of the cable, and the two ends of the cable holder 9 fit on the surface of the insulation layer 2 at the connection between the top of the cryogenic box 1 and the top cover 4, so that the cable remains sealed at the lead-out position, and the cable is fixed without swinging, so as to avoid affecting the connection reliability between the cable and the first temperature sensor 7 and the cryogenic tip clearance sensor 8, thereby ensuring the measurement accuracy of the first temperature sensor 7 and the cryogenic tip clearance sensor 8. The insulation layer 2 at the connection between the top of the cryogenic box 1 and the top cover 4 can preferably be an elastic material such as wool felt. When the top cover 4 is covered with the cryogenic box 1, the top cover 4 can press the insulation layer 2 to reduce the heat exchange inside and outside the cryogenic box 1.

[0099] The temperature control component includes a first temperature sensor 7, a data collector 10, a computer 12, a temperature controller 13 and a second temperature sensor 18; the first temperature sensor 7 is sealed and packaged in a seal 5, the cable of the first temperature sensor 7 is led out of the seal 5 and the deep cold box 1 and is connected to the input end of the data collector 10, the output end of the sensor drive conditioning module 11 is connected to the input end of the data collector 10, the output end of the data collector 10 is connected to the input end of the computer 12, the output end of the computer 12 is connected to the input end of the temperature controller 13 with a temperature display 14, and the output end of the temperature controller 13 is connected to the solenoid valve 16 and the heater 17; the second temperature sensor 18 is arranged in the deep cold box 1, and the output end of the second temperature sensor 18 is connected to the input end of the temperature controller 13.

[0100] The data collector 10 collects the temperature data of the first temperature sensor 7 and the test data of the cryogenic blade tip clearance sensor 8, and transmits them to the computer 12. The control software installed in the computer 12 is used to write the temperature control instruction, and the temperature control instruction is sent to the temperature controller 13 through the computer 12. The temperature controller 13 can adopt the PLC controller of the prior art. The temperature controller 13 controls the on and off of the heater 17 and the solenoid valve 16 according to the temperature control instruction, thereby controlling the heater 17 to heat the deep cold box 1 or providing -196°C nitrogen gas to cool the deep cold box 1 through the solenoid valve 16. In the process of heating or cooling, the real-time temperature in the deep cold box 1 is fed back to the temperature controller 13 through the second temperature sensor 18, which is convenient for controlling the heating speed and cooling speed to ensure the temperature control accuracy. At the same time, due to the setting of the seal 5, there is a certain difference between the actual working temperature of the deep cryogenic blade tip clearance sensor 8 and the temperature in the deep cold box 1. The temperature change in the seal 5 is monitored in real time by the first temperature sensor 7 to ensure that the temperature change range of the low temperature cycle life test of the deep cryogenic blade tip clearance sensor 8 is consistent with the actual ambient temperature change range.

[0101] The seal 5 contains a simulated blade 6 which is sealed and packaged inside. The simulated blade 6 is arranged facing the deep cryogenic blade tip clearance sensor 8. The first temperature sensor 7 of the temperature control assembly is located between the simulated blade 6 and the deep cryogenic blade tip clearance sensor 8. The arrangement of the simulated blade 6 can verify whether the deep cryogenic blade tip clearance sensor 8 can operate normally and maintain good working performance.

[0102] The seal 5 is arranged in the cryogenic box 1 of the cycle life test box through the support frame 20, so that the seal 5 is located beside the heating coil of the heater 17 and the air outlet of the temperature reduction air supply pipe 19, ensuring that the heating and cooling processes can directly act on the deep low temperature blade tip clearance sensor 8.

[0103] Please see attached Figure 2 The surface of the support frame 20 that contacts the seal 5 is provided with a plurality of through holes 21 at intervals. The matrix arrangement of the through holes 21 can reduce the barrier effect of the support frame 20 on hot and cold air, increase the temperature rise and fall rate of the deep low temperature blade tip clearance sensor 8 in the seal 5, and reduce the temperature difference between the inside and outside of the seal 5. Preferably, the support frame 20 can adopt a steel frame structure.

[0104] Please see attached Figure 4 , a cycle life test method for a deep cryogenic blade tip clearance sensor, comprising the following steps:

[0105] Step 1: The simulated blade 6 , the first temperature sensor 7 and the deep low temperature blade tip clearance sensor 8 are sealed and independently packaged in a deep cold box 1 .

[0106] Step 1.1: Determine whether the temperature range and sealing performance of the cryogenic box 1 of the cycle life test chamber meet the test requirements. If so, perform step 1.2. If not, replace the cryogenic box 1 that meets the test requirements (i.e., with a stronger refrigeration capacity and a larger working power).

[0107] The requirement for the temperature range of the cycle life test chamber is: the lowest test temperature of the deep low temperature blade tip clearance sensor 8 in the cycle life test is T min , the maximum test temperature is T max , then the real-time temperature T in the deep freezer 1 satisfies T min ≤T≤T max .

[0108] Since the cables of the first temperature sensor 7 and the cryogenic tip clearance sensor 8 are led out from the joint between the cryogenic box 1 and the top cover 4, and since the cables themselves are not covered with thermal insulation materials, the complete sealing of the cryogenic box 1 cannot be guaranteed, and the heat conduction rate of the cable lead-out part is relatively fast. The sealing performance requirements of the cycle life test chamber are: when the temperature in the cryogenic box 1 reaches the minimum test temperature, the heat Q transferred from the cryogenic box 1 to the seal 5 (the heat of the seal 5 includes the heat of the simulated blade 6 inside the seal 5, the first temperature sensor 7 and the cryogenic tip clearance sensor 8, the same below) is equal to the maximum value of the heat q transferred from the cable lead-out part to the outside world max Q”>q max The heat Q" transferred from the cryogenic box 1 to the sealing member 5 includes the cooling heat Q transferred from the cryogenic box 1 to the sealing member 5 during the cooling stage. 1 and the heating heat Q transferred from the cryogenic box 1 to the sealing member 5 during the heating stage 2 .

[0109] During the cooling phase:

[0110] The cooling heat Q transferred from the cryogenic box 1 to the sealing member 5 is 1 The calculation formula is:

[0111]

[0112] Among them, k 1 The box cooling heat Q' is used for the cooling coefficient of the seal 5 (including the simulated blade 6 inside the seal 5, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8, the same below), k 1 is a constant and k 1 ≥1, which can be determined by experiments. Generally, most of the box cooling heat Q' is used for changing the temperature inside the cryogenic box 1, and only a small part is used for changing the temperature of the sealing member 5.

[0113] S 1 is the outer surface area of ​​the seal 5 , and S is the inner surface area of ​​the cryogenic box 1 .

[0114] Q' is the temperature drop in the test chamber of the deep cold box 1 (i.e., the temperature drop from the starting temperature T 1 Change temperature to cooling end temperature T 2 ) The required box cooling heat, Q' is calculated as:

[0115]

[0116] Among them, U is the cooling rate, ρ is the density of nitrogen, C p is the specific heat capacity of nitrogen, d is the inner diameter of the cryogenic box 1, and l is the inner wall height of the cryogenic box 1.

[0117] During the warming phase:

[0118] The temperature rise heat Q transferred from the cryogenic box 1 to the sealing member 5 is 2 The calculation formula is:

[0119]

[0120] Among them, k 2 The heat W' required for the temperature rise in the test chamber of the cryogenic box 1 is used for the temperature rise coefficient of the seal 5 (including the simulated blade 6 inside the seal 5, the first temperature sensor 7 and the cryogenic tip clearance sensor 8, the same below), k 2 is a constant and k 2 ≥1, which can be determined experimentally; generally, most of the heat W' required for the temperature rise in the test chamber of the cryogenic box 1 is used for the temperature change inside the cryogenic box 1, and only a small part is used for the temperature change of the seal 5.

[0121] W' is the temperature rise in the test chamber of the deep cold box 1 (i.e., the temperature rise from the starting temperature T 1 'Change temperature to heating end temperature T 2 ') The calculation formula for the heat required, W' is:

[0122]

[0123] Wherein, U' is the heating rate. The calculation formula of the heat q transferred from the cable lead-out part to the outside is:

[0124]

[0125] Where, λ is the thermal conductivity of the cable, D is the diameter of the cable, T is the real-time temperature in the deep cold box 1, T 3 is the external environment temperature of the cryogenic box 1.

[0126] When the real-time temperature T in the deep freezer 1 drops to the cooling end temperature T 2When q is 0, the temperature difference between the inside and outside of the deep cold box 1 is the largest, and the heat transferred from the cable lead-out part to the outside world also reaches the maximum value, that is, max .

[0127] Step 1.2: The simulated blade 6 , the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 are sealed in the sealing member 5 .

[0128] Step 1.3: Install the seal 5 in the cryogenic box 1 through the support frame 20, ensuring that the cryogenic tip clearance sensor 8 is close to the source of heating and cooling.

[0129] Step 1.4: The cables of the first temperature sensor 7 and the deep cryogenic blade tip clearance sensor 8 are led out of the seal 5 and out of the cryogenic box 1 through the cable holder 9. When leading out the cables, the reliability of the connection between the first temperature sensor 7 and the deep cryogenic blade tip clearance sensor 8 and their cables should be ensured to ensure the effectiveness and accuracy of parameter collection.

[0130] Step 1.5: Connect the deep cryogenic tip clearance sensor 8 to the sensor drive conditioning module 11, connect the first temperature sensor 7 to the data acquisition device 10, and connect the computer 12 through the data acquisition device 10, open the acquisition software of the computer 12, and observe the status of the acquisition signal. If the receiving voltage signal and temperature value of the deep cryogenic tip clearance sensor 8 can be displayed normally in the acquisition software, the status is normal, otherwise the deep cryogenic tip clearance sensor 8 needs to be repaired or replaced.

[0131] Step 1.6: Cover the top cover 4 on the cryogenic box 1 to isolate the inside of the cryogenic box 1 from the outside. Ensure that the serial ports of the temperature control components are connected in good condition, the temperature data collected by the second temperature sensor 18 is accurate, and the temperature display 14 can display normally, otherwise perform maintenance.

[0132] Step 2: Set the temperature change process parameters of the cycle life test through the computer 12 of the temperature control component, and calculate the low temperature holding time H according to the temperature change process parameters. dhold And high temperature holding time H dhold .

[0133] The temperature change process parameters are determined by the requirements of the low temperature cycle life test of the blade tip clearance sensor. The temperature change process parameters include: the cooling start temperature T 1 , cooling end temperature T 2 , cooling time H d , cooling speed U, heating starting temperature T 1 '、Heating end temperature T 2 '、Heating time H u , heating rate U' and the number of heating and cooling repetitions s and other parameters.

[0134] The cooling time Hd The calculation formula is:

[0135]

[0136] The heating time H u The calculation formula is:

[0137]

[0138] Since the cables of the deep cryogenic blade tip clearance sensor 8 and the first temperature sensor 7 are in contact with the external environment, the external heat will be continuously transferred from the cable lead-out part to the interior of the deep cryogenic box 1 through the cables. Therefore, the actual cooling speed in the seal 5 is inconsistent with the ideal cooling speed in the deep cryogenic box 1. The temperature in the deep cryogenic box 1 needs to be reduced to the cooling end temperature T 2 Keep warm for a while.

[0139] The low temperature holding time H dhold The calculation method is:

[0140] Step S1-1: Cooling from the starting temperature T in the cryogenic box 1 1 Drop to the cooling end temperature T 2 When the ideal cooling temperature T of the seal 5 is calculated 4 (The temperature of the seal 5 includes the temperature of the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 inside the seal 5, the same below), and the calculation formula is:

[0141]

[0142] Among them, C ps is the specific heat capacity of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 inside it, the same below), ρ s is the density of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 therein, the same below).

[0143] Step S1-2: using the lumped parameter method to represent the temperature change process of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 therein, the same below).

[0144] The lumped parameter method formula for the temperature change process of the seal 5 is:

[0145]

[0146] Among them, λ 1 is the thermal conductivity of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 inside it, the same below), S1 is the outer surface area of ​​the seal 5, V 1 is the volume of the seal 5, τ is the temperature of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 inside it, the same below) from t 1 Change to t 2 The time required, t 1 is the temperature T from which the temperature is lowered in the deep freezer 1 1 Drop to the cooling end temperature T 2 The ideal cooling temperature of the seal 5, t 2 It is the cooling test temperature of the deep low temperature blade tip clearance sensor 8.

[0147] Step S1-3: When t 2 =T min When t is t, the temperature of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8, the same below) is calculated according to formula (6) from t 1 Change to t 2 The time τ required is the low temperature holding time H dhold .

[0148] Since the cables of the cryogenic tip clearance sensor 8 and the first temperature sensor 7 are in contact with the external environment, the external heat will be continuously transferred from the cable lead-out part to the interior of the cryogenic box 1 through the cables. Therefore, the actual heating speed in the seal 5 is inconsistent with the ideal heating speed in the cryogenic box 1. The temperature needs to be raised to the end temperature T in the cryogenic box 1. 2 'Then keep warm for a while.

[0149] The high temperature holding time H uhold The calculation method is:

[0150] Step S2-1: In the cryogenic box 1, the temperature is raised from the starting temperature T 1 'Raise to the heating end temperature T 2 ', calculate the ideal heating temperature T of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature blade tip clearance sensor 8, the same below) 5 , the calculation formula is:

[0151]

[0152] Step S2-2: The temperature variation process of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8 therein, the same below) is represented by using the lumped parameter method.

[0153] The lumped parameter method formula for the temperature change process of the seal 5 is:

[0154]

[0155] Wherein, τ' is the temperature of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8, the same below) from t 1 'Change to t 2 'The time required, t 1 ' is the temperature T from the start of heating in the deep cold box 1 1 'Raise to the heating end temperature T 2 The ideal heating temperature of the seal 5 at ', t 2 ' is the heating test temperature of the deep low temperature blade tip clearance sensor 8.

[0156] Step S2-3: When t 2 '=T max When t is t, the temperature of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature tip clearance sensor 8, the same below) is calculated according to formula (6-1) from t 1 'Change to t 2 'The required time τ', which is the holding time H at high temperature uhold .

[0157] Step 3: The computer 12 sends a temperature control instruction to the temperature controller 13, and the temperature controller 13 implements the cycle heating and cooling in the deep cold box 1 according to the temperature control instruction. Click the start test button on the software control interface of the computer 12, and the cycle of heating and cooling can be controlled by the software program. In order to ensure the safety of the test, a pause button can be set on the software control interface of the computer 12. After pressing the pause button, the solenoid valve 16 and the heater 17 are closed, and the entire device stops working.

[0158] When the temperature in the deep freezer 1 is lowered, the step 3 further comprises the following sub-steps:

[0159] Step 3.1.1: The computer 12 calculates the cooling heat Q required to achieve the cooling speed U in the deep cold box 1, and sets the ideal cooling curve according to the cooling speed U. The calculation formula of the cooling heat Q is as follows:

[0160]

[0161] Wherein, d is the inner diameter of the cryogenic box 1, l is the inner wall height of the cryogenic box 1, L is the wall thickness of the cryogenic box 1; T is the real-time temperature in the cryogenic box 1, T 3 is the external environment temperature of the cryogenic box 1; Q' is the heat required for cooling the test chamber of the cryogenic box 1, ρ is the density of nitrogen, C p is the specific heat capacity of nitrogen, λ bis the thermal conductivity of the wall of the cryogenic box 1, and △Q is the heat consumed by the heat exchange between the cryogenic box 1 and the external environment.

[0162] Step 3.1.2: The temperature controller 13 opens the solenoid valve 16 to allow the -196°C low-temperature nitrogen in the nitrogen tank 15 to enter the cryogenic box 1 through the temperature-reducing gas supply pipeline 19, thereby reducing the temperature inside the cryogenic box 1.

[0163] Step 3.1.3: The real-time temperature T in the cryogenic box 1 is collected by the second temperature sensor 18 disposed in the cryogenic box 1, and is sent to the computer 12 through the temperature controller 13. The computer 12 generates an actual cooling curve according to the real-time temperature T.

[0164] Step 3.1.4: Compare the ideal cooling curve with the actual cooling curve, and calculate the real-time cooling temperature T of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature blade tip clearance sensor 8, the same below) at the end of the cooling stage of the deep cold box 1 4 ' and the ideal cooling temperature T 4 and the remaining opening time of the solenoid valve 16 is calculated based on the difference, so as to achieve the purpose of accurately controlling the temperature drop in the cryogenic box 1.

[0165] The remaining opening time of the solenoid valve 16 is calculated using the lumped parameter method, and the calculation formula is:

[0166]

[0167] Among them, τ d The seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature blade tip clearance sensor 8, the same below) is cooled by the real-time temperature T 4 'Cool down to the ideal cooling temperature T 4 The time required.

[0168] In step 3.1.4, since the cryogenic box 1 changes temperature mainly through heat convection and heat conduction, when the temperature inside the cryogenic box 1 is similar to the temperature of the heat exchange gas, the temperature change speed of the cryogenic box 1 will decrease significantly, which is normal. However, if the cryogenic box 1 is in the rapid temperature change stage, that is, the temperature change range of the cryogenic box 1 is within T 2 +30 <T<T 1 In the range of -30, the actual cooling speed U d When <0.8U, it is considered that there may be leakage in cryogenic box 1, and cryogenic box 1 needs to be repaired.

[0169] Step 3.1.5: Correct the low temperature holding time H of deep freezer 1 dhold , low temperature insulation correction time H dhold1 =H dhold1 =H dhold+τ d Formula (9).

[0170] Step 3.1.6: When the temperature in the cryogenic box 1 drops to the end temperature T of the cooling stage 2 After that, the temperature controller 13 controls the electromagnetic valve 16 to close, and the cryogenic box 1 is at the cooling end temperature T 2 Insulation, the insulation time is the insulation time at low temperature H dhold1 .

[0171] Step 3.1.7: After the low temperature insulation is completed, the temperature inside the deep cold box 1 is increased.

[0172] When the temperature in the cryogenic box 1 is increased, the step 3 further comprises the following sub-steps:

[0173] Step S3.2.1: The computer 12 calculates the heating amount W required to achieve a heating rate U' in the cryogenic box 1, and sets an ideal heating curve according to the heating rate U'. Since the internal temperature of the cryogenic box 1 is lower than the external environment temperature, the convective heat exchange between the cryogenic box 1 and the external environment helps to achieve the heating rate U' of the cryogenic box 1. Therefore, it can be considered that the heating amount W is equal to the heat W' required for heating the test cavity of the cryogenic box 1.

[0174] Step 3.2.2: The temperature controller 13 turns on the heater 17 to increase the temperature inside the cryogenic box 1.

[0175] Step 3.2.3: The real-time temperature T in the cryogenic box 1 is collected by the second temperature sensor 18 disposed in the cryogenic box 1, and is sent to the computer 12 through the temperature controller 13. The computer 12 generates an actual temperature rise curve according to the real-time temperature T.

[0176] Step 3.2.4: Compare the ideal temperature rise curve with the actual temperature rise curve, and calculate the real-time temperature rise T of the seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature blade tip clearance sensor 8, the same below) at the end of the temperature rise stage of the deep cold box 1 5 ' and the ideal heating temperature T 5 and the remaining opening time of the heater 17 is calculated based on the difference, thereby achieving the purpose of accurately controlling the temperature rise in the cryogenic box 1.

[0177] The remaining opening time of the heater 17 is calculated by using the lumped parameter method, and the calculation formula is:

[0178]

[0179] Among them, τ u The seal 5 (including the simulated blade 6, the first temperature sensor 7 and the deep low temperature blade tip clearance sensor 8, the same below) is heated from the real-time temperature T 5'Heating to the ideal heating temperature T 5 The time required.

[0180] In step 3.2.4, since the cryogenic box 1 changes temperature mainly through heat convection and heat conduction, when the temperature of the cryogenic box is similar to the temperature of the heat exchange gas, the temperature change speed of the cryogenic box 1 will decrease significantly, which is normal. However, if the cryogenic box 1 is in the rapid temperature change stage, that is, the temperature change range of the cryogenic box 1 is within T 1 '+30 <T<T 2 In the range of '-30, the actual heating rate U u <0.8U', cryogenic box 1 may have leakage and other problems, and cryogenic box 1 needs to be repaired.

[0181] Step 3.2.5: Correct the holding time H at high temperature of deep freezer 1 uhold , high temperature insulation correction time H uhold1 =H uhold1 =H uhold +τ u Formula (9-1).

[0182] Step 3.2.6: When the temperature in the cryogenic box 1 rises to the heating end temperature T 2 'After that, the temperature controller 13 controls the heater 17 to turn off, and the cryogenic box 1 is at the heating end temperature T 2 'Insulation, high temperature insulation time length is low temperature insulation time H uhold1 .

[0183] Step 3.2.7: After the high temperature insulation is completed, the temperature in the deep freezer 1 is lowered.

[0184] Step 4: During the heating and cooling cycle in the cryogenic box 1, the data collector 10 of the temperature control component collects data in real time and transmits it to the computer 12. According to the temperature data of the first temperature sensor 7 and the temperature data of the second temperature sensor 18 collected by the data collector 10, the heating rate, cooling rate and insulation time in the cryogenic box 1 can be adjusted more accurately and timely, and it is also helpful to judge the insulation, sealing and other working conditions of the cryogenic box 1. The temperature information can be displayed in real time on the temperature display 14. The signal output of the probe of the cryogenic tip clearance sensor 8 under different test temperatures and cycle conditions collected by the sensor drive conditioning module 11 can determine the working performance and service life of the cryogenic tip clearance sensor 8.

[0185] Embodiment 1:

[0186] In this embodiment, the temperature range of the cycle life test is 25°C to -190°C, the number of cycles s is 200 times, and the cooling rate U and the heating rate U' are both 5°C / min. The deep low temperature blade tip clearance sensor 8 is an optical fiber sensor.

[0187] The parameters of the cryogenic box 1 used in this embodiment are as follows: the inner diameter of the cylindrical cryogenic box 1 is 0.5 m, the inner wall height is 0.5 m, and the wall thickness is 0.1 m. In order to leave a certain threshold, the lowest test temperature T of the cryogenic box 1 used is min The maximum test temperature is -195℃. max The temperature is 30°C. The inner surface area S of the deep freezer 1 is 1.1775 m 2 The outer diameter of the cylindrical seal 5 is 0.1m, the height is 0.15m, and the outer surface area S of the seal 5 is 1 0.0628m 2 , the volume V of the seal 5 1 =0.0012m 3 .

[0188] The diameter D of the cable of the first temperature sensor 7 and the deep low temperature blade tip clearance sensor 8 is 0.05 m, the middle arc of the cable holder 9 is a semicircular arc structure with a diameter of 0.05 m, and the main material of the cable and the cable holder 9 is copper, and the specific heat capacity of copper is 3901 J / (kg·K) and the density is 8900 kg / m 3 , the thermal conductivity λ is 397W / (m·K).

[0189] The specific heat capacity C of the nitrogen in the nitrogen tank 15 p is 2000J / (kg·K), and the density of nitrogen is 802.6993kg / m 3 , k 1 Take 1.

[0190] According to formula (2) The heat Q' required to reduce the temperature in the test chamber of deep cold box 1 is calculated to be 1.576*106J.

[0191] According to formula (1) The heat Q transferred from the cryogenic box 1 to the seal 5 is calculated as follows: 1 8.4*10 4 J.

[0192] According to formula (3) Calculate the heat q transferred from the cable lead-out part to the outside world max 3.4*10 3 J, less than Q 1 . Cryogenic box 1 meets the test requirements.

[0193] The simulated blade 6, the first temperature sensor 7 and the deep cryogenic blade tip clearance sensor 8 are sealed and packaged in the seal 5, and the seal 5 is installed in the deep cryogenic box 1 through the support frame 20 to ensure that the deep cryogenic blade tip clearance sensor 8 is close to the source of heating and cooling. The cables of the first temperature sensor 7 and the deep cryogenic blade tip clearance sensor 8 are led out of the seal 5 and out of the deep cryogenic box 1 through the cable holder 9. The deep cryogenic blade tip clearance sensor 8 is connected to the data acquisition device 10 and the sensor drive conditioning module 11, and connected to the computer 12, and the acquisition software of the computer 12 is opened to observe the state of the acquisition signal. If the acquisition software can normally display that the receiving voltage signal of the deep cryogenic blade tip clearance sensor 8 is greater than 0.2V, and the temperature sensor has a normal indication, then the state is normal, otherwise the deep cryogenic blade tip clearance sensor 8 needs to be repaired or replaced. The top cover 4 is closed on the deep cryogenic box 1 to isolate the inside of the deep cryogenic box 1 from the outside world. There is no "serial port connection is normal" prompt on each serial port of the temperature control component, and the temperature display 14 can show normally.

[0194] Step 2: The temperature variation process parameters of the cycle life test are set by the computer 12. In this embodiment, the temperature reduction process and the temperature increase process are set as two symmetrical processes, that is, the temperature reduction starting temperature T 1 and heating end temperature T 2 ' are all 30℃, the cooling end temperature is T 2 and the heating start temperature T 1 ' are all -195℃. According to formula (4) and formula (4-1), the cooling time H is calculated d and heating time H u Both are |30-(-195)| / 5=45min.

[0195] During the cooling phase:

[0196] When the cooling process in the cryogenic box 1 is completed, according to formula (5) The ideal cooling temperature T of the seal 5 is calculated 4 It is about -106.7°C, and the main material of the seal 5 is copper.

[0197] According to formula (6) The calculation results show that τ = 7.87 min, that is, the temperature of the sealing member 5 can drop to -190°C or below after 7.87 min of heat preservation. In order to retain a certain safety margin, the heat preservation time H at low temperature is set as dhold Set to 20 minutes.

[0198] During the warming phase,

[0199] According to formula (2-1) The heat W' required to heat up the test chamber of deep cold box 1 is calculated to be 1.576*10 6 J.

[0200] According to formula (1-1) The heat Q transferred from the cryogenic box 1 to the seal 5 is calculated as follows: 2 8.4*10 4 J.

[0201] When the temperature rise process in the cryogenic box 1 is completed, according to formula (5-1) The ideal heating temperature T of the seal 5 is calculated 5 About -59.3℃.

[0202] According to formula (6-1) The calculation results show that τ = 7.87 min, that is, the temperature of the sealing member 5 rises to 25°C or above after 7.87 min of heat preservation. In order to retain a certain safety margin, the heat preservation time H at high temperature is set as uhold Set to 20 minutes.

[0203] Step 3: The computer 12 controls the computer 12 to send a temperature control instruction to the temperature controller 13, and the temperature controller 13 realizes the cyclic heating and cooling in the deep cold box 1 according to the temperature control instruction.

[0204] Comparing the ideal cooling curve with the actual cooling curve, the real-time cooling temperature T at the end of the cooling stage of deep cold box 1 4 ' is -180℃, and according to formula (8) τ is calculated d =3min,7.87min+3min <H dhold =20min, therefore, the insulation can still be carried out according to 20min, and the insulation time at low temperature does not need to be corrected.

[0205] Comparing the ideal heating curve with the actual heating curve, the real-time heating temperature T at the end of the heating stage of deep cold box 1 5 ' is 10℃, and according to formula (8-1) we can calculate τ u =3.78min,7.87min+3.78min <H uhold =20min, therefore, the insulation can still be carried out according to 20min, and the insulation time at room temperature does not need to be corrected.

[0206] Step 4: During the 200 cycles of heating and cooling in the cryogenic box 1 , the data collector 10 collects data in real time and transmits it to the computer 12 .

[0207] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cycle life test method for a deep cryogenic blade tip clearance sensor, characterized by: The cycle life test method is implemented by using a cycle life test device of a deep cryogenic blade tip clearance sensor, the cycle life test device comprising a deep cryogenic box (1), a simulated blade (6), a first temperature sensor (7), a deep cryogenic blade tip clearance sensor (8) and a temperature control component; The cycle life test method of the deep cryogenic blade tip clearance sensor comprises the following steps: Step 1: sealing and independently packaging the simulated blade (6), the first temperature sensor (7) and the cryogenic blade tip clearance sensor (8) in a cryogenic box (1); Step 2: Set the temperature change process parameters of the cycle life test through the temperature control component, and calculate the low temperature holding time H according to the temperature change process parameters dhold And high temperature holding time H uhold ; Step 3: The temperature control component realizes cyclic heating and cooling in the deep cold box (1); Step 4: During the heating and cooling cycle in the cryogenic box (1), the temperature control component collects data in real time.

2. The cycle life test method of the deep cryogenic tip clearance sensor according to claim 1 is characterized by: The step 1 comprises the following sub-steps: Step 1.1: Determine whether the temperature range and sealing performance of the cycle life test chamber meet the test requirements. If so, proceed to step 1.

2. If not, replace the cycle life test chamber that meets the test requirements. Step 1.2: sealing the simulated blade (6), the first temperature sensor (7) and the deep low temperature blade tip clearance sensor (8) in a sealing member (5); Step 1.3: Install the seal (5) in the cryogenic box (1); Step 1.4: Lead the cables of the first temperature sensor (7) and the cryogenic tip clearance sensor (8) out of the sealing member (5) and the cryogenic box (1); Step 1.5: Connecting the deep cryogenic blade tip clearance sensor (8) and the first temperature sensor (7) to the temperature control assembly; Step 1.6: Isolate the interior of the cryogenic box (1) from the outside world.

3. The cycle life test method of the deep cryogenic tip clearance sensor according to claim 2 is characterized by: The requirement for the temperature range of the cycle life test chamber is: the lowest test temperature of the deep low temperature blade tip clearance sensor (8) in the cycle life test is T min , the maximum test temperature is T max , then the real-time temperature T in the deep freezer (1) satisfies T min ≤T≤T max .

4. The cycle life test method of the deep cryogenic tip clearance sensor according to claim 2 is characterized by: The sealing performance requirement of the cycle life test box is: when the temperature in the cryogenic box (1) reaches the minimum test temperature, the heat Q" transferred from the cryogenic box (1) to the sealing member (5) is equal to the maximum heat q transferred from the cable lead-out portion to the outside world. max Q”>q max ; The heat Q" transferred from the cryogenic box (1) to the sealing member (5) includes the cooling heat Q1 transferred from the cryogenic box (1) to the sealing member (5) during the cooling stage and the heating heat Q2 transferred from the cryogenic box (1) to the sealing member (5) during the heating stage; The calculation formula for the cooling heat Q1 transferred from the cryogenic box (1) to the sealing element (5) during the cooling stage is: Wherein, k1 is the heat Q' required for cooling the test chamber of the cryogenic box (1), which is used as the cooling coefficient of the sealing member (5), k1 is a constant and k1≥1; S1 is the outer surface area of ​​the sealing member (5), and S is the inner surface area of ​​the cryogenic box (1); Q' is the cooling heat required for the temperature drop in the test chamber of the deep cold box (1). The calculation formula of Q' is: Among them, U is the cooling rate, ρ is the density of nitrogen, C p is the specific heat capacity of nitrogen, d is the inner diameter of the cryogenic box (1), and l is the inner wall height of the cryogenic box (1); The calculation formula for the heating heat Q2 transferred from the cryogenic box (1) to the sealing element (5) during the heating stage is: Wherein, k2 is the heat W' required for heating the test chamber of the cryogenic box (1) and is used as the temperature rise coefficient of the sealing member (5), k2 is a constant and k2≥1; W' is the heat required to raise the temperature in the test chamber of the cryogenic box (1). The calculation formula of W' is: Where, U' is the heating rate; The calculation formula for the heat q transferred from the cable lead-out portion to the outside is: Wherein, λ is the thermal conductivity of the cable, D is the diameter of the cable, T is the real-time temperature in the cryogenic box (1), T3 is the external environment temperature of the cryogenic box (1), and L is the wall thickness of the cryogenic box (1); When the real-time temperature T in the deep cold box (1) drops to the cooling end temperature T2, the heat transferred from the cable lead-out part to the outside world reaches the maximum value q max .

5. The cycle life test method of the deep cryogenic tip clearance sensor according to claim 1 is characterized by: In step 2, the temperature change process parameters include: cooling start temperature T1, cooling end temperature T2, cooling time H d , cooling speed U, heating start temperature T1', heating end temperature T2', heating time H u , heating rate U' and heating and cooling repetition times s; The cooling time H d The calculation formula is: The heating time H u The calculation formula is:

6. The cycle life test method of the deep cryogenic tip clearance sensor according to claim 5 is characterized by: In the cooling stage, the low temperature holding time H dhold The calculation method is: Step S1-1: When the temperature in the cryogenic box (1) drops from the cooling start temperature T1 to the cooling end temperature T2, the ideal cooling temperature T4 of the sealing member (5) is calculated using the following formula: Among them, C ps is the specific heat capacity of the seal (5), ρ s is the density of the seal (5), Q1 is the cooling heat transferred from the cryogenic box (1) to the seal (5), and D is the diameter of the cable; Step S1-2: using a lumped parameter method to represent the temperature change process of the sealing member (5); The lumped parameter method expression formula for the temperature change process of the sealing element (5) is: Wherein, λ1 is the thermal conductivity of the seal (5), S1 is the outer surface area of ​​the seal (5), V1 is the volume of the seal (5), τ is the time required for the temperature of the seal (5) to change from t1 to t2; t1 is the ideal cooling temperature of the seal (5) when the cooling starts at T1 and ends at T2 in the cryogenic box (1), and t2 is the cooling test temperature of the cryogenic tip clearance sensor (8); Step S1-3: When t2 = T min When T min is the minimum test temperature. According to formula (6), the time τ required for the temperature of the seal (5) to change from t1 to t2 is calculated. This time τ is the low temperature insulation time H dhold ; In the heating stage, the high temperature holding time H uhold The calculation method is: Step S2-1: When the temperature rises from the starting temperature T1' to the ending temperature T2' in the cryogenic box (1), the ideal rising temperature T5 of the sealing member (5) is calculated using the following formula: Wherein: Q2 is the temperature increase heat transferred from the cryogenic box (1) to the sealing member (5); Step S2-2: using a lumped parameter method to represent the temperature change process of the sealing element (5); The lumped parameter method expression formula for the temperature change process of the sealing element (5) is: Wherein, τ' is the time required for the temperature of the sealing member (5) to change from t1' to t2', t1' is the ideal temperature rise of the sealing member (5) when the temperature rises from the heating start temperature T1' to the heating end temperature T2' in the cryogenic box (1), and t2' is the heating test temperature of the cryogenic tip clearance sensor (8); Step S2-3: When t2'=T max When T max is the maximum test temperature. According to formula (6-1), the time τ' required for the temperature of the seal (5) to change from t1' to t2' is calculated. This time τ' is the high temperature insulation time H uhold .

7. The cycle life test method of the deep cryogenic tip clearance sensor according to claim 1 is characterized by: In the step 3, the temperature control component comprises a data acquisition device (10), a computer (12), a temperature controller (13) and a second temperature sensor (18); the cycle life test device further comprises a nitrogen tank (15), a solenoid valve (16), a heater (17) and a temperature drop gas supply pipeline (19); the nitrogen tank (15) is filled with -196°C nitrogen; the nitrogen tank (15) is connected to the cycle life test chamber via the temperature drop gas supply pipeline (19); the solenoid valve (16) is arranged on the temperature drop gas supply pipeline (19) and is electrically connected to the temperature control component; the heater (17) is electrically connected to the temperature control component, and the heating coil of the heater (17) is arranged inside the cycle life test chamber; When the temperature in the cryogenic box (1) is lowered, step 3 further comprises the following sub-steps: Step 3.1.1: The computer (12) calculates the cooling heat Q required to achieve the cooling speed U in the deep cold box (1), and sets an ideal cooling curve according to the cooling speed U. The calculation formula of the cooling heat Q is as follows: Wherein, d is the inner diameter of the cryogenic box (1), l is the inner wall height of the cryogenic box (1), L is the wall thickness of the cryogenic box (1); T is the real-time temperature inside the cryogenic box (1), T3 is the external environment temperature of the cryogenic box (1); Q' is the heat required for cooling the test cavity of the cryogenic box (1), ρ is the density of nitrogen, C p is the specific heat capacity of nitrogen, λ b is the thermal conductivity of the wall of the cryogenic box (1), △Q is the heat consumed by the heat exchange between the cryogenic box (1) and the external environment; U is the cooling rate; Step 3.1.2: The temperature controller (13) opens the solenoid valve (16) to allow the -196°C low-temperature nitrogen in the nitrogen tank (15) to enter the cryogenic box (1) through the temperature-reducing gas supply pipeline (19), thereby reducing the temperature inside the cryogenic box (1); Step 3.1.3: The real-time temperature T in the cryogenic box (1) is collected by a second temperature sensor (18) disposed in the cryogenic box (1), and is sent to the computer (12) through the temperature controller (13). The computer (12) generates an actual cooling curve according to the real-time temperature T; Step 3.1.4: Compare the ideal cooling curve with the actual cooling curve, calculate the difference between the real-time cooling temperature T4' of the sealing member (5) at the end of the cooling stage of the deep cold box (1) and the ideal cooling temperature T4, and calculate the remaining opening time of the solenoid valve (16) based on the difference, and the calculation formula is: Among them, τ d is the time required for the seal (5) to cool from the real-time cooling temperature T4' to the ideal cooling temperature T4, λ1 is the thermal conductivity of the seal (5), S1 is the surface area of ​​the seal (5), V1 is the volume of the seal (5), C ps is the specific heat capacity of the seal (5), T2 is the cooling end temperature; Step 3.1.5: Correct the low temperature insulation time H of the deep freezer (1) dhold , low temperature insulation correction time H dhold1 for: H dhold1 = H dhold + τ d Equation (9); Step 3.1.6: When the temperature in the cryogenic box (1) drops to the cooling end temperature T2, the temperature controller (13) controls the solenoid valve (16) to close, and the cryogenic box (1) is kept warm at the cooling end temperature T2 for a time equal to the low temperature holding time H. dhold1 ; Step 3.1.7: After the low temperature insulation is completed, the temperature inside the deep freezer (1) is increased.

8. The cycle life test method of the deep cryogenic blade tip clearance sensor according to claim 7 is characterized in that: In step 3.1.4 described above, the temperature change range of the cryogenic box (1) is within the range of T2 + 30 < T < T1 - 30, and when the actual cooling rate U d < 0.8U, it is considered that there may be a leak in the cryogenic box (1), and the cryogenic box (1) needs to be repaired; where: T1 is the starting temperature of cooling, and U is the cooling rate.

9. The cycle life test method of the deep cryogenic tip clearance sensor according to claim 7, characterized in that: When the temperature in the cryogenic box 1 is increased, step 3 further comprises the following sub-steps: Step S3.2.1: The computer (12) calculates the heating amount W required to achieve a heating rate U' in the cryogenic box (1), the heating amount W being equal to the heating amount W' required to heat the test chamber of the cryogenic box (1), and sets an ideal heating curve according to the heating rate U'; Step 3.2.2: The temperature controller (13) turns on the heater (17) to increase the temperature inside the cryogenic box (1); Step 3.2.3: The real-time temperature T in the cryogenic box (1) is collected by a second temperature sensor (18) disposed in the cryogenic box (1), and is sent to the computer (12) through the temperature controller (13). The computer (12) generates an actual temperature rise curve according to the real-time temperature T; Step 3.2.4: Compare the ideal heating curve with the actual heating curve, calculate the difference between the real-time heating temperature T5' of the seal (5) at the end of the heating stage of the cryogenic box (1) and the ideal heating temperature T5, and calculate the remaining opening time of the heater (17) based on the difference, and the calculation formula is: Among them, τ u is the time required for the seal (5) to heat up from the real-time heating temperature T5' to the ideal heating temperature T5, λ1 is the thermal conductivity of the seal (5), S1 is the surface area of ​​the seal (5), V1 is the volume of the seal (5), C ps is the specific heat capacity of the seal (5), T1' is the starting temperature of heating; Step 3.2.5: Correct the holding time H at high temperature in the cryogenic box (1) uhold , high temperature insulation correction time H uhold1 For: H uhold1 =H uhold +τ u Formula (9-1); Step 3.2.6: When the temperature in the cryogenic box (1) rises to the temperature T2', the temperature controller 13 controls the heater (17) to turn off, and the cryogenic box (1) is kept warm at the temperature T2'. The high temperature keeping time is equal to the low temperature keeping time H. uhold1 ; Step 3.2.7: After the high temperature insulation is completed, the temperature in the deep freezer (1) is lowered.

10. The cycle life test method of the deep cryogenic blade tip clearance sensor according to claim 9, characterized in that: In the said step 3.2.4, the temperature variation range of the cryogenic box (1) is within the range of T1'+30 < T < T2'-30, and the actual heating rate U u < 0.8U', there may be a leak in the cryogenic box (1), and the cryogenic box (1) needs to be repaired; where: T1' is the starting temperature of heating, and U' is the heating rate.

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