Test method for verifying influence of blade tip clearance of gas compressor on performance

Abstract

The invention relates to the technical field of gas compressor test design, in particular to a test method for verifying the influence of gas compressor blade tip clearance on performance, which comprises the following steps: constructing an input data sequence formed by inlet temperature and rotating speed; a theoretical model of the inlet temperature and the blade tip thermal-state gap is constructed; acquiring an actual blade tip thermal clearance corresponding to the rotating speed of one group of input data of the gas compressor, and acquiring a correction model; obtaining a final inlet temperature and a final rotating speed corresponding to each to-be-verified blade tip thermal-state gap according to the corrected correction model; an actual performance curve of the gas compressor at the final rotating speed is obtained; and evaluating the influence value of the blade tip thermal-state clearance on the performance of the gas compressor. By obtaining the performance characteristics of the gas compressor under different blade tip gaps, the problems of repeated disassembly, assembly, coping and loading and unloading caused by a traditional method are avoided, so that the test efficiency is improved, and the development period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of compressor test design, and in particular to a test method for verifying the influence of compressor blade tip clearance on performance. Background Art

[0002] As one of the three core components of an aircraft engine, the compressor converts mechanical energy into the pressure potential energy and kinetic energy of the gas, thereby providing high-pressure ratio air for the combustion chamber. The compressor usually includes rotor blades, stator blades, and casings. The rotor blades rotate around the engine shaft and do work on the gas, thereby increasing the gas pressure and kinetic energy. Due to the high-speed rotation of the rotor blades, the blades are subjected to the combined effects of centrifugal force, thermal stress, and aerodynamic force. The higher the speed or temperature, the greater the deformation and elongation of the blades. Therefore, there must be enough tip clearance between the blades and the stationary casing during assembly to ensure that the rotor blade tips will not be scraped against the casing at high temperatures or high speeds. However, the hot clearance of the rotor blade tip has an important influence on the compressor efficiency and aerodynamic stability. Usually, if the tip clearance is too large, the compressor efficiency and surge margin will be reduced. If the tip clearance is too small, the rotor blades will be scraped against the casing. In summary, the determination of the tip clearance must not only meet the performance requirements, but also avoid scraping and affecting safe operation. Therefore, during the compressor development process, it is necessary to conduct experimental verification on different blade tip clearances to obtain the influence of clearance on compressor performance and provide a basis for determining the final blade tip clearance.

[0003] At present, in order to obtain the influence of different tip clearances on compressor performance, for axial flow compressors, the compressor performance under small clearance state is first recorded, then the compressor is disassembled and the rotor blade tip is ground to increase the tip clearance. After that, the assembly is completed and the compressor is put on the test again, and the process is repeated many times until the requirements are met. For centrifugal compressors, although there is no need to grind the centrifugal impeller, the adjustment pad at the impeller cover needs to be replaced, which also requires disassembly and re-testing. Since each test can only verify one tip clearance state, it is necessary to continuously disassemble and assemble the compressor test piece to change the tip clearance state. The above method consumes a lot of manpower and material resources, has a long verification cycle, and is inefficient.

[0004] Regarding the adjustment of the hot clearance of the compressor, in addition to the above-mentioned measures to change the cold clearance of the blade tip, the state of the casing can also be changed in the hot state, so as to achieve the purpose of adjusting the tip clearance in the hot state. The existing technology deals with the test method of the compressor, which divides the compressor casing into an inner wall and an outer wall, passes a fluid into the channel between them, and heats the fluid so that heat is transferred between the fluid and the compressor casing wall, thereby changing the temperature of the compressor casing, adjusting the thermal expansion of the casing, and achieving the adjustment of the tip clearance. However, this method requires the compressor casing to be modified, which changes the original state of the compressor, and the compressor casing is provided with an inner wall and an outer wall, which increases the complexity of the structure.

[0005] In summary, the existing method can only verify one blade tip clearance state in each test. Changing the blade tip clearance state requires re-disassembly, disassembly, grinding, and assembly, which leads to a long cycle and low test efficiency. In addition, after multiple disassembly and assembly of the compressor, the relevant joint surfaces are prone to wear, and there is a risk of leakage, which affects the accuracy of the test.

[0006] Therefore, it is necessary to provide a test method for verifying the effect of compressor tip clearance on performance to solve the above problems. Summary of the invention

[0007] The present invention provides a test method for verifying the influence of compressor blade tip clearance on performance, so as to solve the problem that the existing method can only verify one blade tip clearance state in each test, and changing the blade tip clearance state requires re-disassembly, disassembly, grinding and assembly, which has a long cycle and low test efficiency. In addition, after the compressor is disassembled and assembled many times, the relevant joint surfaces are prone to wear, there is a risk of leakage, and the accuracy of the test is affected.

[0008] A test method for verifying the influence of compressor tip clearance on performance of the present invention adopts the following technical scheme, including: The inlet temperature and speed corresponding to the compressor in the design state are converted into the inlet temperature and speed under the standard atmospheric conditions at sea level, and an input data sequence consisting of the inlet temperature and speed is constructed based on the temperature and speed under the standard atmospheric conditions at sea level; According to each set of input data in the input data sequence, and by using a three-dimensional fluid algorithm, a thermal analysis algorithm, and a finite element calculation method, a radial deformation amount of a rotor blade and a corresponding casing position under each set of input data in the input data sequence is obtained; According to the cold clearance between the blade and the casing in the assembled state, combined with the radial deformation of the rotor blade and the corresponding casing position under each set of input data, the theoretical blade tip hot clearance corresponding to the compressor under each set of input data is obtained, and based on the inlet temperature of each set of input data and the corresponding theoretical blade tip hot clearance, a theoretical model of inlet temperature and blade tip hot clearance is constructed; The temperature at the compressor inlet is adjusted to the inlet temperature of one set of input data, and the compressor speed is pushed to the speed of the set of input data to obtain the actual blade tip hot clearance of the compressor under the set of input data; the theoretical model is corrected according to the difference between the actual blade tip hot clearance of the compressor under the set of input data and the theoretical blade tip hot clearance to obtain a corrected model; Inputting the hot clearance of the blade tip to be verified into the correction model, obtaining the final inlet temperature corresponding to each hot clearance of the blade tip to be verified, and obtaining the final speed of the compressor; Detect the blade tip hot clearance value corresponding to the final inlet temperature and final speed of the compressor. If the blade tip hot clearance value is consistent with the verified blade tip hot clearance, obtain the actual performance curve of the compressor at the final speed; if the blade tip hot clearance value is inconsistent with the verified blade tip hot clearance, adjust the final inlet temperature until the detected blade tip hot clearance value is consistent with the verified blade tip hot clearance, and obtain the actual performance curve of the compressor when they are consistent; The influence of the hot tip clearance on the compressor performance is evaluated based on the actual performance curve and the preset design performance curve, wherein the influence values ​​include: the influence value of the flow at the blocking point, the influence value of the peak efficiency and the influence value of the pressure ratio at the burst point.

[0009] Preferably, the rotation speed expression under standard atmospheric conditions at sea level is:

[0010] In the formula, T0 represents the corresponding inlet temperature of the compressor under the design state; N0 represents the corresponding speed of the compressor under the design state; It represents the compressor inlet temperature under standard atmospheric conditions at sea level; Indicates the speed of the compressor under standard atmospheric conditions at sea level.

[0011] Preferably, the step of constructing an input data sequence consisting of inlet temperature and rotation speed under standard atmospheric conditions at sea level is: Increasing or decreasing the inlet temperature on the basis of the inlet temperature under standard atmospheric conditions at sea level to obtain a plurality of adjusted temperatures, and obtaining an adjusted speed corresponding to each adjusted temperature; Based on the inlet temperature under standard atmospheric conditions at sea level, each adjusted inlet temperature, and the rotational speed corresponding to each inlet temperature as a group of input data, an input data sequence consisting of temperature and rotational speed is obtained.

[0012] Preferably, the expression of the adjusted speed is:

[0013] Where, T1 represents the compressor inlet temperature under standard atmospheric conditions at sea level; N1 represents the compressor speed under standard atmospheric conditions at sea level; Indicates the compressor's first The inlet temperature after the first adjustment; Indicates the compressor's first The speed after adjustment.

[0014] Preferably, the step of obtaining the radial deformation of the rotor blade and the corresponding casing position under each set of input data in the input data sequence is: The inlet temperature and the corresponding rotation speed in each set of input data are used as input conditions, and the internal flow field distribution of the compressor corresponding to each set of data is obtained by using a three-dimensional numerical calculation method; Conduct thermal analysis to obtain the temperature field distribution corresponding to the blade disk and compressor casing; According to the internal flow field distribution, the temperature field distribution of the blade disk and the compressor casing, the radial deformation of the rotor blade and the corresponding casing position is obtained.

[0015] Preferably, the step of obtaining the theoretical blade tip hot clearance corresponding to each set of input data of the compressor is: According to the cold clearance between the blade and the casing in the assembled state, the theoretical blade tip hot clearance of the compressor corresponding to each set of input data is obtained based on the radial deformation of the rotor blade and the casing position corresponding to each set of input data, that is, the expression of the theoretical blade tip hot clearance is: Δ hot =Δ cold -Δ blade +Δ case In the formula, Δ hot Represents the theoretical blade tip hot clearance; Δ cold Indicates the cold clearance between the blade and the casing; Δ blade Indicates the radial deformation of the rotor blade; Δ case Indicates the radial deformation of the receiver position.

[0016] Preferably, the steps of constructing a theoretical model of inlet temperature and blade tip hot clearance are: The relationship between the inlet temperature of each set of input data and the corresponding theoretical blade tip thermal clearance is used to construct a theoretical model of inlet temperature and blade tip thermal clearance.

[0017] Preferably, the step of correcting the theoretical model according to the difference between the actual blade tip hot clearance and the theoretical blade tip hot clearance of the compressor under one set of input data is: According to the difference between the actual blade tip hot clearance and the theoretical blade tip hot clearance of the compressor under one set of input data, the theoretical blade tip hot clearance of each set of input data is corrected to the actual blade tip hot clearance; A correction model of the inlet temperature and the blade tip hot clearance is obtained according to the actual blade tip hot clearance and the inlet temperature in the group of input data.

[0018] Preferably, the congestion point flow impact value is: the ratio of the congestion point flow of the actual performance curve to the congestion point flow of the preset design performance curve; the peak efficiency impact value is: the difference between the peak efficiency of the actual performance curve and the peak efficiency of the preset design performance curve; the surge point pressure ratio impact value is: the ratio of the surge point pressure ratio of the actual performance curve to the surge point pressure ratio of the preset design performance curve.

[0019] Preferably, the temperature at the compressor inlet is adjusted to each final inlet temperature, and the compressor speed is pushed to the final speed corresponding to the final inlet temperature, so that the blade tip hot clearance value corresponding to the compressor at the final inlet temperature and final speed can be detected.

[0020] The beneficial effects of the present invention are: In order to verify the influence of hot clearance of blades on compressor performance, the traditional method adopts changing the cold clearance between blades and casing. Each test can only verify the influence of one hot clearance value of blade tip on compressor performance. When verifying multiple sets of hot clearance of blade tips, it is necessary to repeatedly disassemble and assemble the compressor, and the test cycle is long. The core idea of ​​the present invention is to change the deformation of compressor rotor blades and casing by adjusting the inlet temperature, so as to achieve the purpose of adjusting the hot clearance of blade tips. When verifying multiple sets of hot clearance of blade tips, it is only necessary to change the inlet temperature and the corresponding rotation speed, and give the corresponding specific value through the hot clearance model of blade tip, without repeatedly disassembling and assembling the compressor, so it can significantly shorten the time cost and improve the test efficiency.

[0021] That is, firstly, a theoretical model of inlet temperature and blade tip hot clearance is constructed, that is, according to the input data sequence consisting of inlet temperature and speed, three-dimensional fluid algorithm, thermal analysis algorithm and finite element calculation method are used, combined with the cold clearance between the blade and the casing in the assembled state, to obtain the theoretical blade tip hot clearance of the compressor under each set of input data. Secondly, based on one set of input data, experimental verification is carried out to obtain the actual blade tip hot clearance, and the theoretical model is corrected in combination with the experimental results of this set of input data. The construction of the above-mentioned theoretical model of inlet temperature and blade tip hot clearance effectively establishes the mapping relationship between inlet temperature and blade tip hot clearance. Through this model, the inlet temperature corresponding to the blade tip hot clearance to be verified can be directly determined, and by conducting experimental verification on a set of input data and correcting the theoretical model according to the results, the accuracy of the theoretical model is further improved. Through the corrected model, the inlet temperature corresponding to the blade tip hot clearance to be verified can be directly determined, providing inlet temperature conditions for experimental verification, avoiding blind adjustment of the inlet temperature in the experiment, and saving experimental time. Finally, the inlet temperature corresponding to the hot clearance of the blade tip to be verified is obtained according to the corrected model. Combined with the inlet temperature, the actual performance curve of the compressor under the hot clearance of the blade tip to be verified is quickly obtained through the test, and the specific impact value of the hot clearance of the blade tip on the compressor performance is evaluated in combination with the preset design performance curve. Therefore, compared with the traditional method of verifying the impact of hot clearance on blade tip, the idea of ​​adjusting the hot clearance of the compressor blade tip by changing the inlet temperature proposed in the present invention can avoid repeated disassembly and assembly of the engine on and off the platform, thereby improving the test efficiency. In addition, the present invention also establishes a corrected theoretical model of inlet temperature and hot clearance of blade tip, which can give the inlet temperature corresponding to the hot clearance of blade tip to be verified, avoiding the blind adjustment of the inlet temperature during the test and improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A flow chart of a test method for verifying the effect of compressor tip clearance on performance according to the present invention; Figure 2 Schematic diagram of the hot clearance of the compressor blade tip in an embodiment of the present invention; Figure 3 is a system block diagram of the compressor test system of the present invention; Figure 4 It is a three-dimensional simulation schematic diagram of the diversion basin structure in the present invention; Figure 5A schematic diagram of different state points of the compressor constant speed line in the present invention; Figure 6 A schematic diagram showing the comparison of pressure ratio characteristics of the compressor under different blade tip hot clearances in the present invention; Figure 7 It is a schematic diagram comparing the efficiency characteristics of the compressor under different hot tip clearances in the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] An embodiment of a test method for verifying the influence of compressor tip clearance on performance of the present invention is based on Figure 3 The compressor test system shown in the figure is used for experiments. Figure 1 As shown, this embodiment specifically includes: S1, constructing an input data sequence consisting of inlet temperature and speed; Specifically, the inlet temperature and speed corresponding to the compressor in the design state are converted into the inlet temperature and speed under the standard atmospheric conditions at sea level, and an input data sequence consisting of the inlet temperature and speed is constructed based on the temperature and speed under the standard atmospheric conditions at sea level.

[0026] For example, in a specific embodiment, the inlet temperature T0 and the speed N0 corresponding to the compressor design state are converted to the standard atmospheric conditions at sea level. After conversion, the corresponding inlet temperature of the compressor is T1=288.15K and the speed is ,Through similar transformation, it is ensured that the flow state inside the compressor under the two conditions is similar.

[0027] Exemplarily, in a specific embodiment, the steps of constructing an input data sequence consisting of inlet temperature and rotational speed are as follows: increasing or decreasing the inlet temperature on the basis of the inlet temperature under standard atmospheric conditions at sea level to obtain multiple adjusted temperatures, and obtaining an adjusted rotational speed corresponding to each adjusted temperature; based on the inlet temperature under standard atmospheric conditions at sea level, each adjusted inlet temperature, and the rotational speed corresponding to each inlet temperature as a set of input data, obtaining an input data sequence consisting of temperature and rotational speed.

[0028] That is, based on the inlet temperature T1 = 288.15K, increase or decrease the compressor inlet temperature to Ti, then the adjusted speed The expression is:

[0029] Where, T1 represents the compressor inlet temperature under standard atmospheric conditions at sea level; N0 represents the compressor speed under design conditions; Indicates the compressor under standard atmospheric conditions at sea level. The inlet temperature after the first adjustment; Indicates the compressor under standard atmospheric conditions at sea level. The speed after adjustment.

[0030] So far, we can get the results of different inlet temperatures (T1, T2, T3, T4… ) and the corresponding speed (N1, N2, N3, N4… ), each inlet temperature and the corresponding speed constitute a set of input data, and multiple sets of input data constitute an input data sequence.

[0031] S2. Construct a theoretical model of inlet temperature and blade tip thermal clearance; Specifically, according to each group of input data in the input data sequence, and using a three-dimensional fluid algorithm, a thermal analysis algorithm and a finite element calculation method, the radial deformation of the rotor blades and the corresponding casing position under each group of input data in the input data sequence is obtained; according to the cold clearance between the blades and the casing in the assembled state, combined with the radial deformation of the rotor blades and the corresponding casing position under each group of input data, the corresponding theoretical blade tip hot clearance of the compressor under each group of input data is obtained, and based on the inlet temperature of each group of input data and the corresponding theoretical blade tip hot clearance, a theoretical model of the inlet temperature and the blade tip hot clearance is constructed.

[0032] Exemplarily, in a specific embodiment, the steps for obtaining the radial deformation of the rotor blades and the corresponding casing positions under each set of input data in the input data sequence are: taking the inlet temperature and rotation speed in each set of input data as input conditions, and using a three-dimensional numerical calculation method to obtain the internal flow field distribution corresponding to the compressor under each set of data; and performing thermal analysis to obtain the temperature field distribution corresponding to the blade disk and the compressor casing; and obtaining the radial deformation of the rotor blades and the corresponding casing positions based on the internal flow field distribution, the temperature field distribution corresponding to the blade disk and the compressor casing.

[0033] Exemplarily, in a specific embodiment, according to the cold clearance between the blade and the casing in the assembled state, the radial deformation of the rotor blade and the corresponding casing position under each set of input data, the step of obtaining the theoretical blade tip hot clearance corresponding to each set of input data of the compressor is: According to the cold clearance between the blade and the casing in the assembled state, the theoretical blade tip hot clearance of the compressor corresponding to each set of input data is obtained based on the radial deformation of the rotor blade and the casing position corresponding to each set of input data, that is, the expression of the theoretical blade tip hot clearance is: Δ hot =Δ cold -Δ blade +Δ case In the formula, Δ hot Represents the theoretical blade tip hot clearance; Δ cold Indicates the cold clearance between the blade and the casing; Δ blade represents the radial deformation of the rotor blade, Δ case Indicates the radial deformation of the receiver position.

[0034] Exemplarily, in a specific embodiment, the steps of constructing a theoretical model of inlet temperature and blade tip hot clearance are as follows: according to the blade tip hot clearance (C1, C2, C3, C4...) of the compressor corresponding to different inlet temperatures (T1, T2, T3, T4...), the relationship between the inlet temperature of each group of input data and the corresponding theoretical blade tip hot clearance can be constructed based on the relationship. A theoretical model of inlet temperature and blade tip hot clearance of the compressor is established C=f(T), wherein the blade tip hot clearance range can cover the verified blade tip hot clearance.

[0035] S3, obtaining the actual blade tip hot clearance corresponding to the speed of the compressor at one set of input data, and obtaining a correction model; Specifically, the temperature at the compressor inlet is adjusted to the inlet temperature of one set of input data, and the compressor speed is pushed to the speed of the set of input data to obtain the actual blade tip hot clearance of the compressor under the set of input data; the theoretical model is corrected according to the difference between the actual blade tip hot clearance of the compressor under the set of input data and the theoretical blade tip hot clearance to obtain a corrected model.

[0036] Exemplarily, in this embodiment, since the difference between the actual hot blade tip clearance of the compressor and the corresponding theoretical hot blade tip clearance is basically unchanged under each set of input data, in order to reduce the amount of calculation, one set of input data in the input data sequence is used, that is, in this embodiment, according to the i-th set of input data (Ti, Ni) in the input data sequence, the inlet temperature of the compressor is adjusted to the inlet temperature Ti by using the intake temperature control system, and then the compressor speed is pushed to the speed Ni, and the actual hot blade tip clearance value Ci' of the compressor is recorded by the clearance sensor.

[0037] Exemplarily, in a specific embodiment, the theoretical model is corrected by combining the deviation value between the actual blade tip hot clearance Ci' obtained by experiment and the theoretical blade tip hot clearance Ci obtained by theoretical calculation in step S2, so as to obtain a corrected model C'=f'(T) of inlet temperature and blade tip hot clearance.

[0038] At this point, the corrected model can be obtained.

[0039] S4. Obtaining the final inlet temperature and final rotation speed corresponding to each blade tip hot clearance to be verified according to the corrected correction model; Specifically, the hot clearance of the blade tip to be verified is input into the correction model to obtain the final inlet temperature corresponding to each hot clearance of the blade tip to be verified, and the final speed of the compressor is obtained; illustratively, the hot clearance of the blade tip to be verified Cj' is input into the correction model C'=f'(T), the final inlet temperature Tj corresponding to each hot clearance of the blade tip to be verified is obtained, and the final speed Nj of the compressor is obtained.

[0040] S5, obtaining an actual performance curve of the compressor at a final speed; Specifically, the blade tip hot clearance value corresponding to the final inlet temperature and final speed of the compressor is detected. If the blade tip hot clearance value is consistent with the verified blade tip hot clearance, the actual performance curve of the compressor at the final speed is obtained; if the blade tip hot clearance value is inconsistent with the verified blade tip hot clearance, the final inlet temperature is adjusted until the detected blade tip hot clearance value is consistent with the verified blade tip hot clearance, and the actual performance curve of the compressor when they are consistent is obtained.

[0041] For example, in a specific embodiment, the inlet temperature control system is used to first adjust the compressor inlet temperature to the final inlet temperature Tj, and then the compressor speed is pushed to the final speed , the tip hot clearance value at this time is collected according to the clearance sensor. If the collected tip hot clearance is consistent with the tip hot clearance Cj' to be verified, the performance curve of the compressor at the speed Nj is recorded as the actual performance curve; if the collected tip hot clearance is smaller than the tip hot clearance Cj' to be verified, then on the basis of Tj, the intake temperature control system is used to increase the compressor inlet temperature. If the measured clearance value is greater than the clearance value Cj' to be verified, then on the basis of Tj, the intake temperature control system is used to reduce the compressor inlet temperature. Among them, the speed Nj changes with the actual inlet temperature Tj, and the relationship between the two is By adjusting the inlet temperature and the corresponding speed, until the tip hot clearance measured by the clearance sensor is consistent with the tip hot clearance Cj' to be verified, the compressor performance curve is recorded as the actual performance curve.

[0042] At this point, the actual performance curve of the compressor at the final speed can be obtained.

[0043] S6. Evaluate the influence of blade tip hot clearance on compressor performance; Specifically, the influence of the hot tip clearance on the compressor performance is evaluated based on the actual performance curve and the preset design performance curve, wherein the influence values ​​include: the influence value of the blockage flow, the influence value of the peak efficiency and the influence value of the surge point pressure ratio.

[0044] Exemplarily, in a specific embodiment, the congestion point flow impact value is: the congestion point flow impact value is: the flow ratio of the congestion point flow of the actual performance curve and the congestion point flow of the preset design performance curve; the peak efficiency impact value is: the efficiency difference between the peak efficiency of the actual performance curve and the peak efficiency of the preset design performance curve; the surge point pressure ratio impact value is: the pressure ratio ratio of the surge point pressure ratio of the actual performance curve and the surge point pressure ratio of the preset design performance curve.

[0045] The present embodiment is described in detail below with reference to the accompanying drawings: In accordance with the compressor development requirements, the following is an example to verify the specific impact of the compressor performance when the hot tip clearance is 0.25mm, 0.3mm, and 0.4mm respectively.

[0046] like Figure 3 As shown, the compressor test system includes: an air intake temperature control system, a pressure stabilizing box, a compressor test piece, an exhaust system, a transmission system, and a power system. Among them, the power system, the transmission system, and the compressor test piece are connected in sequence, and the power system provides power to the compressor test piece through the transmission system; the air intake temperature control system, the pressure stabilizing box, the compressor test piece, and the exhaust system are connected in sequence to form a gas flow path. The gas enters from the air intake temperature control system, passes through the pressure stabilizing box and the compressor test piece in sequence, and is finally discharged through the exhaust system. The compressor test piece includes a guide basin, an inlet section, a compressor body, and an outlet section. The guide basin, the inlet section, the compressor body, and the outlet section are connected in sequence. Figure 4 As shown, the inlet profile of the guide basin is a double twisted line design, followed by a cylindrical section, and small holes with a diameter of 1-2 mm are opened on the wall of the cylindrical section. The number of small holes is not less than 10 and is evenly distributed in the circumferential direction. The distance from the tangent point of the double twisted line profile and the cylindrical section to the center of the small hole is 0.2 times the diameter of the guide basin. A chamber is set on the outside of the small hole, and the chamber is connected to the small hole. Four static pressure holes are set on the wall of the chamber for measuring the static pressure of the airflow.

[0047] based on Figure 3 and Figure 4The compressor test system and compressor test piece shown in the figure are provided with 4 static pressure measurement holes on the chamber wall of the cylindrical section of the guide basin, and 2 five-point comb-shaped total temperature probes and 2 five-point comb-shaped total pressure probes are provided at the measuring section of the inlet section of the compressor test piece, and the above radial measuring points are distributed according to equal annular surface areas, and 4 three-point comb-shaped total temperature probes and 4 five-point total pressure probes are provided at the measuring section of the outlet section, and the radial measuring points are also distributed according to equal annular surface areas. At the casing position corresponding to the compressor rotor blade, 3 clearance sensors are evenly arranged circumferentially to measure the hot clearance of the blade tip in real time.

[0048] Step 1: Convert the temperature and speed of the compressor under the design state to the standard atmospheric conditions at sea level. After conversion, the corresponding inlet temperature of the compressor is 288.15K and the speed is 35200r / min. Based on the inlet temperature of 288.15K and the speed of 35200r / min, the input data sequence consisting of the inlet temperature and the speed is obtained.

[0049] Step 2: For the input data under the standard atmospheric state at sea level, use the three-dimensional fluid simulation calculation tool to obtain the internal flow field distribution at the compressor inlet under the standard atmospheric state at sea level. The internal flow field distribution includes: the pressure distribution of the blades and the casing, and the gas temperature pressure distribution at the air inlet position of the blade disc cavity. On this basis, use the thermal analysis calculation tool to obtain the temperature field distribution of the blade disc and the compressor casing. Take the internal flow field distribution and temperature field distribution as input, and use the finite element calculation method to obtain the radial deformation of the rotor blades and the corresponding casing position. The radial deformation of the rotor blades is 0.56mm, and the radial deformation of the casing position is 0.1mm. At the same time, combined with the cold clearance between the blades and the casing in the assembled state of 0.77mm, it is calculated that under the conditions of inlet temperature of 288.15 and speed of 35200r / min, the theoretical tip hot clearance between the rotor blades and the casing is 0.31mm (0.77-0.56+0.1).

[0050] Based on the above calculation results and combined with the verification clearance requirements, the theoretical tip hot clearance between the compressor rotor blade and the casing under the conditions of inlet temperatures of 248.15K, 268.15K, and 298.15K is calculated respectively. To ensure the similarity of the internal flow of the compressor, the speed corresponding to different inlet temperatures is calculated according to the formula The speed results are shown in Table 1. The range of the blade tip hot clearance value is 0.22mm~0.42mm. The blade tip hot clearance values ​​to be verified (0.25mm, 0.3mm, 0.4mm) are within the above range.

[0051] Table 1

[0052] After obtaining the change law of the inlet temperature and the calculated tip hot clearance shown in Table 1, the tip hot clearance calibration was carried out under the condition of an inlet temperature of 288.15K in combination with the compressor test system. The temperature at the compressor inlet was adjusted to 288.15K by using the intake temperature control system. Then, the compressor speed was gradually pushed to 35200r / min by adjusting the power system. By adjusting the opening of the exhaust throttle valve, different state points of the compressor at this speed were recorded in turn. The state points at least include the blocking point, design point, peak efficiency point, and breathing point. The flow rate, pressure ratio, and efficiency of the compressor at each state point (i.e., blocking point and breathing point) were obtained by using the static pressure measurement point of the guide basin and the measurement point of the inlet section and the outlet section probe, so as to obtain the pressure ratio characteristics and efficiency characteristics. At the same time, the measured hot clearance value was obtained according to the clearance sensor. The hot clearance value at this time was 0.3mm, as shown in FIG. Figure 5 As shown, Figure 5 A schematic diagram of different state points of the compressor speed line is given. Figure 6 is the schematic diagram of the compressor pressure ratio characteristics. Figure 7 It is a schematic diagram of the efficiency characteristics of the compressor.

[0053] Considering that the calculated theoretical blade tip hot clearance value is 0.31 mm under the condition of inlet temperature of 288.15 K, the deviation between the two is 0.01 mm, that is, this embodiment believes that the calculated theoretical blade tip hot clearance value is larger than the measured actual hot clearance value, and the deviation is 0.01 mm. Therefore, the deviation is subtracted from the hot clearance corresponding to other inlet temperatures to obtain the corrected blade tip hot clearance shown in Table 2.

[0054] Table 2

[0055] For the required tip hot clearances of 0.25mm and 0.4mm to be verified, combined with the relationship between the inlet temperature and the corrected tip hot clearance, the corresponding inlet temperatures can be calculated as 299.3K and 253.9K by linear interpolation. Considering that the tip clearance value does not change much, linear interpolation can be used for calculation. If the clearance changes greatly, polynomials or B-splines can be used for interpolation, and the speed conversion formula can be used. The final speeds corresponding to the final inlet temperatures of 299.3K and 253.9K are 35874.6r / min and 33041.9r / min respectively.

[0056] The two blade tip hot clearances at the final inlet temperatures of 299.3K and 253.9K and the corresponding final speeds of 35874.6r / min and 33041.9r / min were verified respectively: First, the inlet temperature is adjusted to the final inlet temperature of 299.3K by the intake temperature control system, and the speed is pushed to the final speed of 35874.6r / min. At this time, the actual hot clearance of the blade tip measured by the clearance sensor is 0.24mm. The inlet temperature is appropriately reduced by 1.5K by the intake temperature control system, and the speed is reduced accordingly according to the conversion formula. At this time, the hot clearance of the blade tip is 0.25mm, which is consistent with the verified clearance value. After that, the inlet temperature and the corresponding speed are fixed, the opening of the exhaust throttle valve is adjusted, and the performance characteristics of different state points of the compressor at the same speed are recorded in turn to obtain the actual performance curve. The steps for the hot clearance of the blade tip of 0.4mm and the verification of the hot clearance of the blade tip of 0.25mm are the same, and will not be repeated in this embodiment.

[0057] By adjusting the inlet temperature, the actual performance curves of the compressor blade tip hot clearances of 0.25mm, 0.3mm, and 0.4mm were obtained, as well as the design performance curves corresponding to the preset compressor blade tip hot clearances of 0.25mm, 0.3mm, and 0.4mm. Figure 6 and Figure 7 By comparing the preset design performance curve with the actual performance curve, the influence of the tip hot clearance on the compressor is obtained as shown in Table 3. Through comparative analysis, it can be concluded that as the hot clearance increases from 0.25mm to 0.4mm, the compressor flow decreases by 1.2%, the peak efficiency decreases by 0.5 percentage points, and the surge pressure ratio decreases by 2.5%.

[0058] Table 3

[0059] It should be noted that, in this embodiment, the hot clearance of the blade tip is 0.25 mm as the reference state, and the states of the hot clearances of the other blade tips are compared with the reference state.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A test method for verifying the effect of compressor tip clearance on performance, characterized in that: include: The inlet temperature and speed corresponding to the compressor in the design state are converted into the inlet temperature and speed under the standard atmospheric conditions at sea level, and an input data sequence consisting of the inlet temperature and speed is constructed based on the temperature and speed under the standard atmospheric conditions at sea level; According to each set of input data in the input data sequence, and by using a three-dimensional fluid algorithm, a thermal analysis algorithm, and a finite element calculation method, a radial deformation amount of a rotor blade and a corresponding casing position under each set of input data in the input data sequence is obtained; According to the cold clearance between the blade and the casing in the assembled state, combined with the radial deformation of the rotor blade and the corresponding casing position under each set of input data, the theoretical blade tip hot clearance corresponding to the compressor under each set of input data is obtained, and based on the inlet temperature of each set of input data and the corresponding theoretical blade tip hot clearance, a theoretical model of inlet temperature and blade tip hot clearance is constructed; The temperature at the compressor inlet is adjusted to the inlet temperature of one set of input data, and the compressor speed is pushed to the speed of the set of input data, so as to obtain the actual blade tip hot clearance of the compressor under the set of input data; The theoretical model is corrected according to the difference between the actual blade tip hot clearance and the theoretical blade tip hot clearance of the compressor under the group of input data to obtain a corrected model; Inputting the hot clearance of the blade tip to be verified into the correction model, obtaining the final inlet temperature corresponding to each hot clearance of the blade tip to be verified, and obtaining the final speed of the compressor; Detect the blade tip hot clearance value corresponding to the final inlet temperature and final speed of the compressor. If the blade tip hot clearance value is consistent with the verified blade tip hot clearance, obtain the actual performance curve of the compressor at the final speed; If the blade tip hot clearance value is inconsistent with the verified blade tip hot clearance, the final inlet temperature is adjusted until the blade tip hot clearance value detected is consistent with the verified blade tip hot clearance, and the actual performance curve of the compressor is obtained when they are consistent; The influence of the hot tip clearance on the compressor performance is evaluated based on the actual performance curve and the preset design performance curve, wherein the influence values ​​include: the influence value of the flow at the blocking point, the influence value of the peak efficiency and the influence value of the pressure ratio at the burst point.

2. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: The rotation speed expression under standard atmospheric conditions at sea level is: In the formula, T0 represents the corresponding inlet temperature of the compressor under the design state; N0 represents the corresponding speed of the compressor under the design state; It represents the compressor inlet temperature under standard atmospheric conditions at sea level; Indicates the speed of the compressor under standard atmospheric conditions at sea level.

3. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: The steps to construct the input data sequence consisting of inlet temperature and speed are: Increasing or decreasing the inlet temperature based on the inlet temperature under standard atmospheric conditions at sea level to obtain a plurality of adjusted temperatures, and obtaining an adjusted speed corresponding to each adjusted temperature; Based on the inlet temperature under standard atmospheric conditions at sea level, each adjusted inlet temperature, and the rotational speed corresponding to each inlet temperature as a group of input data, an input data sequence consisting of temperature and rotational speed is obtained.

4. A test method for verifying the effect of compressor tip clearance on performance according to claim 3, characterized in that: The expression of the adjusted speed is: Where, T1 represents the compressor inlet temperature under standard atmospheric conditions at sea level; N1 represents the compressor speed under standard atmospheric conditions at sea level; Indicates the compressor's first The inlet temperature after the first adjustment; Indicates the compressor's first The speed after adjustment.

5. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: The steps for obtaining the radial deformation of the rotor blade and the corresponding casing position under each set of input data in the input data sequence are: The inlet temperature and the corresponding speed are used as input conditions, and the internal flow field distribution of the compressor corresponding to each set of data is obtained using a three-dimensional numerical calculation method. Conduct thermal analysis to obtain the temperature field distribution corresponding to the blade disk and compressor casing; According to the internal flow field distribution, the temperature field distribution of the blade disk and the compressor casing, the radial deformation of the rotor blade and the corresponding casing position is obtained.

6. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: The steps to obtain the theoretical blade tip hot clearance corresponding to each set of input data of the compressor are: According to the cold clearance between the blade and the casing in the assembled state, the theoretical blade tip hot clearance of the compressor corresponding to each set of input data is obtained based on the radial deformation of the rotor blade and the casing position corresponding to each set of input data, that is, the expression of the theoretical blade tip hot clearance is: D hot =D cold -D blade +D case In the formula, Δ hot Represents the theoretical blade tip hot clearance; Δ cold Indicates the cold clearance between the blade and the casing; Δ blade Indicates the radial deformation of the rotor blade; Δ case Indicates the radial deformation of the receiver position.

7. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: The steps to construct the theoretical model of inlet temperature and blade tip hot clearance are: The relationship between the inlet temperature of each set of input data and the corresponding theoretical blade tip thermal clearance is used to construct a theoretical model of inlet temperature and blade tip thermal clearance.

8. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: The steps for correcting the theoretical model according to the difference between the actual blade tip hot clearance and the theoretical blade tip hot clearance of the compressor under one set of input data are as follows: According to the difference between the actual blade tip hot clearance and the theoretical blade tip hot clearance of the compressor under one set of input data, the theoretical blade tip hot clearance of each set of input data is corrected to the actual blade tip hot clearance; A correction model of the inlet temperature and the blade tip hot clearance is obtained according to the actual blade tip hot clearance and the inlet temperature in the group of input data.

9. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: The impact value of the congestion point flow is: the ratio of the congestion point flow of the actual performance curve to the congestion point flow of the preset design performance curve; The peak efficiency impact value is: the difference between the peak efficiency of the actual performance curve and the peak efficiency of the preset design performance curve; The impact value of the surge point pressure ratio is: the ratio of the surge point pressure ratio of the actual performance curve to the surge point pressure ratio of the preset design performance curve.

10. A test method for verifying the effect of compressor tip clearance on performance according to claim 1, characterized in that: By adjusting the temperature at the compressor inlet to each final inlet temperature and pushing the compressor speed to the final speed corresponding to the final inlet temperature, the blade tip hot clearance value corresponding to the compressor at the final inlet temperature and final speed can be detected.

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