An experimental method for verifying the influence of compressor tip clearance on performance

Abstract

The present invention relates to the technical field of compressor test design, and particularly relates to a test method for verifying the influence of compressor tip clearance on performance, including: constructing an input data sequence composed of inlet temperature and rotational speed; constructing a theoretical model of inlet temperature and tip hot clearance; obtaining the actual tip hot clearance corresponding to the rotational speed of a set of input data of the compressor, and obtaining a correction model; obtaining the final inlet temperature and final rotational speed corresponding to each tip hot clearance to be verified according to the corrected correction model; obtaining the actual performance curve of the compressor at the final rotational speed; and evaluating the influence value of the tip hot clearance on the performance of the compressor. The present invention avoids the problems of repeated disassembly, grinding, and mounting and demounting brought by the traditional method by obtaining the performance characteristics of the compressor under different tip clearances, thereby improving the test efficiency and shortening the development cycle.

Description

Technical Field

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

[0002] As one of the three core components of an aeroengine, the function of a compressor is to convert mechanical energy into the pressure potential energy and kinetic energy of gas, so as to provide high-pressure ratio air for the combustion chamber. A compressor usually includes components such as rotor blades, stator blades and a casing. 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 action of centrifugal force, thermal stress and aerodynamic force. The higher the rotational speed or temperature, the greater the deformation and elongation of the blades. Therefore, sufficient tip clearance must be left between the blades and the stationary casing during assembly to ensure that the rotor tips do not rub against the casing at high temperatures or high rotational speeds. However, the hot tip clearance of the rotor has an important influence on the compressor efficiency and aerodynamic stability. Generally, too large a tip clearance will lead to a decrease in compressor efficiency and surge margin, and too small a tip clearance will cause rubbing between the rotor blades and the casing. In summary, the determination of the tip clearance should not only meet the performance requirements but also avoid rubbing and affecting safe operation. Therefore, during the development of a compressor, it is necessary to conduct tests and verifications for different tip clearances to obtain the influence law of the clearance on the compressor performance, so as to provide a basis for the determination of the final tip clearance.

[0003] At the present stage, in order to obtain the influence of different tip clearances on the compressor performance, for an axial compressor, first, the compressor performance is recorded under the small clearance state, then it is disassembled from the test bench, the rotor tips are ground to make the tip clearance larger, then it is assembled, and then it is tested again on the test bench. This process is repeated many times until the requirements are met. For a centrifugal compressor, although it is not necessary to grind the centrifugal impeller, it is necessary to replace the adjustment pad at the impeller shroud, and it also needs to be disassembled from the test bench and reinstalled. Since only one tip clearance state can be verified in each test, it is necessary to continuously disassemble and assemble the compressor test piece to change the tip clearance state. The above method consumes a large amount of manpower and material resources, and has a long verification cycle and low efficiency.

[0004] For the adjustment of the hot clearance of the compressor, in addition to the measures of changing the cold tip clearance mentioned above, the state of the casing can also be changed during the hot state, so as to achieve the purpose of adjusting the tip clearance under the hot state. The existing technology for dealing with the compressor test method divides the compressor casing into an inner wall and an outer wall, and fluid is introduced into the channel between them. By heating the fluid, heat transfer occurs between the fluid and the compressor casing wall, thereby changing the temperature of the compressor casing and adjusting the thermal expansion amount of the casing, so as to realize the adjustment of the tip clearance. However, this method requires the modification of the compressor casing, which changes the original state of the compressor, and the setting of the inner wall and outer wall of the compressor casing increases the structural complexity.

[0005] To sum up, the existing method can only verify one tip clearance state in each test. Changing the tip clearance state requires re-dismounting, disassembling, grinding, and assembling, resulting in a long cycle and low test efficiency. In addition, after the compressor is disassembled and assembled multiple times, the relevant joint surfaces are prone to wear, there is a risk of air leakage, which affects the accuracy of the test.

[0006] Therefore, a test method for verifying the influence of the compressor tip clearance on performance is needed to solve the above problems. Summary of the Invention

[0007] The present invention provides a test method for verifying the influence of the compressor tip clearance on performance to solve the problem that the existing method can only verify one tip clearance state in each test. Changing the tip clearance state requires re-dismounting, disassembling, grinding, and assembling, resulting in a long cycle and low test efficiency. In addition, after the compressor is disassembled and assembled multiple times, the relevant joint surfaces are prone to wear, there is a risk of air leakage, which affects the accuracy of the test.

[0008] A test method for verifying the influence of the compressor tip clearance on performance of the present invention adopts the following technical solutions, including:

[0009] Convert the inlet temperature and rotational speed corresponding to the compressor under the design state into the inlet temperature and rotational speed under the sea-level standard atmospheric conditions, and construct an input data sequence composed of the inlet temperature and rotational speed based on the temperature and rotational speed under the sea-level standard atmospheric conditions;

[0010] According to each set of input data in the input data sequence, and using the three-dimensional fluid algorithm, thermal analysis algorithm, and finite element calculation method, obtain the radial deformation amounts of the rotor blades and the corresponding casing positions under each set of input data in the input data sequence;

[0011] According to the cold clearance between the blades and the casing in the assembled state, combined with the radial deformation amounts of the rotor blades and the corresponding casing positions under each set of input data, obtain the corresponding theoretical tip hot clearance of the compressor under each set of input data, and construct a theoretical model of the inlet temperature and the tip hot clearance based on the inlet temperature of each set of input data and the corresponding theoretical tip hot clearance.

[0012] Adjust the temperature at the compressor inlet to the inlet temperature of one set of input data, and push the compressor speed to the speed of this set of input data to obtain the actual tip hot clearance of the compressor under this set of input data; correct the theoretical model according to the difference between the actual tip hot clearance and the theoretical tip hot clearance of the compressor under this set of input data to obtain a corrected correction model;

[0013] Input the tip hot clearance to be verified into the correction model to obtain the corresponding final inlet temperature for each tip hot clearance to be verified, and obtain the final speed of the compressor;

[0014] Detect the tip hot clearance value corresponding to the compressor at the final inlet temperature and the final speed. If the tip hot clearance value is consistent with the verified tip hot clearance, obtain the actual performance curve of the compressor at this final speed; if the tip hot clearance value is inconsistent with the verified tip hot clearance, adjust this final inlet temperature until the detected tip hot clearance value is consistent with the verified tip hot clearance, and obtain the actual performance curve of the compressor when they are consistent;

[0015] Evaluate the influence value of the tip hot clearance on the compressor performance according to the actual performance curve and the preset design performance curve. Among them, the influence value includes: the influence value of the blocked flow, the influence value of the peak efficiency, and the influence value of the surge pressure ratio.

[0016] Preferably, the speed expression under the sea-level standard atmospheric conditions is:

[0017]

[0018] In the formula, T0 represents the inlet temperature corresponding to the compressor under the design condition; N0 represents the speed corresponding to the compressor under the design condition; represents the inlet temperature of the compressor under the sea-level standard atmospheric conditions; represents the speed corresponding to the compressor under the sea-level standard atmospheric conditions.

[0019] Preferably, the steps to construct the input data sequence composed of the inlet temperature and the speed under the sea-level standard atmospheric conditions are:

[0020] Increase or decrease the inlet temperature on the basis of the inlet temperature under the sea-level standard atmospheric conditions to obtain multiple adjusted temperatures, and obtain the adjusted speed corresponding to each adjusted temperature;

[0021] Based on the inlet temperature under the sea-level standard atmospheric conditions, each adjusted inlet temperature, and the speed corresponding to each inlet temperature as a set of input data, obtain the input data sequence composed of the temperature and the speed.

[0022] Preferably, the adjusted rotational speed expression is:

[0023]

[0024] In the formula, T1 represents the inlet temperature corresponding to the compressor under standard atmospheric conditions at sea level; N1 represents the rotational speed corresponding to the compressor under standard atmospheric conditions at sea level; represents the inlet temperature after the th adjustment based on the standard atmospheric conditions at sea level for the compressor; represents the rotational speed after the th adjustment based on the standard atmospheric conditions at sea level for the compressor.

[0025] Preferably, the steps for obtaining the radial deformation amounts of the rotor blades and the corresponding casing positions under each set of input data in the input data sequence are as follows:

[0026] Taking the inlet temperature and the corresponding rotational speed in each set of input data as input conditions, using a three-dimensional numerical calculation method to obtain the corresponding internal flow field distribution of the compressor under each set of data;

[0027] Performing a thermal analysis to obtain the temperature field distributions corresponding to the bladed disk and the compressor casing;

[0028] According to the internal flow field distribution and the temperature field distributions corresponding to the bladed disk and the compressor casing, obtaining the radial deformation amounts of the rotor blades and the corresponding casing positions.

[0029] Preferably, the steps for obtaining the theoretical tip hot clearance of the compressor under each set of input data are as follows:

[0030] Based on the cold clearance between the blade and the casing in the assembled state and on the basis of the radial deformation amounts corresponding to the rotor blade and the casing positions under each set of input data, obtaining the theoretical tip hot clearance of the compressor under each set of input data, that is, the expression for the theoretical tip hot clearance is:

[0031] Δ hot =Δ cold -Δ blade +Δ case

[0032] In the formula, Δ hot represents the theoretical tip hot clearance; Δ cold represents the cold clearance between the blade and the casing; Δ blade represents the radial deformation amount of the rotor blade; Δ case represents the radial deformation amount of the casing position.

[0033] Preferably, the steps for constructing a theoretical model of the inlet temperature and the tip hot clearance are as follows:

[0034] Construct a theoretical model of the inlet temperature and the tip hot clearance by using the relationship between the inlet temperature of each set of input data and the corresponding theoretical tip hot clearance.

[0035] Preferably, the steps of correcting the theoretical model according to the difference between the actual tip hot clearance and the theoretical tip hot clearance of the compressor under one set of input data are as follows:

[0036] Correct the theoretical tip hot clearance of each set of input data to the actual tip hot clearance according to the difference between the actual tip hot clearance and the theoretical tip hot clearance of the compressor under one set of input data;

[0037] Obtain a corrected model of the inlet temperature and the tip hot clearance based on the actual tip hot clearance and the inlet temperature in this set of input data.

[0038] Preferably, the influence value of the choke flow rate is the ratio of the choke flow rate of the actual performance curve to the choke flow rate of the preset design performance curve; the influence value of the peak efficiency is the difference between the peak efficiency of the actual performance curve and the peak efficiency of the preset design performance curve; the influence value of the surge pressure ratio is the ratio of the surge pressure ratio of the actual performance curve to the surge pressure ratio of the preset design performance curve.

[0039] Preferably, adjust the temperature at the inlet of the compressor to each final inlet temperature and push the compressor speed to the final speed corresponding to this final inlet temperature, then the tip hot clearance value corresponding to the compressor at the final inlet temperature and the final speed can be detected.

[0040] The beneficial effects of the present invention are as follows:

[0041] To verify the influence of the blade hot clearance on the performance of the compressor, the traditional method is to change the cold clearance between the blade and the casing. Each test can only verify the influence of one tip hot clearance value on the performance of the compressor. When verifying multiple sets of tip hot clearances, the compressor needs to be disassembled and assembled repeatedly off the test bench, and the test period is long. The core idea of the present invention is to change the deformation amounts of the compressor rotor blades and the casing by adjusting the inlet temperature, so as to achieve the purpose of adjusting the tip hot clearance. When verifying multiple sets of tip hot clearances, only the inlet temperature and the corresponding speed need to be changed, and the corresponding specific values are given by the tip hot clearance model, without repeatedly disassembling and assembling the compressor off the test bench. Therefore, the time cost can be significantly shortened and the test efficiency can be improved.

[0042] That is, first, a theoretical model of the inlet temperature and the tip hot clearance is constructed. Specifically, based on the input data sequence composed of the inlet temperature and the rotational speed, using three-dimensional fluid algorithms, thermal analysis algorithms, and finite element calculation methods, and combining the cold clearance between the blade and the casing in the assembled state, the theoretical tip hot clearance of the compressor is obtained for each set of input data. Secondly, experimental verification is carried out based on one set of input data to obtain the actual 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 the inlet temperature and the tip hot clearance effectively establishes the mapping relationship between the inlet temperature and the tip hot clearance. Through this model, the inlet temperature corresponding to the tip hot clearance to be verified can be directly determined. And by carrying out 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 tip hot clearance to be verified can be directly determined, providing the inlet temperature condition for experimental verification, avoiding the blind adjustment of the inlet temperature in the experiment, and saving experimental time. Finally, according to the corrected model, the inlet temperature corresponding to the tip hot clearance to be verified is obtained. Combining this inlet temperature, the actual performance curve of the compressor under the tip hot clearance to be verified is quickly obtained through experiments, and the specific influence value of the tip hot clearance on the performance of the compressor is evaluated in combination with the preset design performance curve. Therefore, compared with the traditional experimental verification method for the influence of the tip hot clearance, the idea of adjusting the tip hot clearance of the compressor by changing the inlet temperature proposed in the present invention can avoid repeatedly disassembling and assembling the engine on and off the test bench, improving the experimental efficiency. And the present invention also establishes a corrected theoretical model of the inlet temperature and the tip hot clearance, which can give the inlet temperature corresponding to the tip hot clearance to be verified, avoiding the blind adjustment of the inlet temperature during the experiment and improving the experimental efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0044] Figure 1 It is a flowchart of an experimental method for verifying the influence of the tip clearance of a compressor on its performance according to the present invention;

[0045] Figure 2 It is a schematic diagram of the tip hot clearance of the compressor in the embodiment of the present invention;

[0046] Figure 3 It is a system block diagram of the compressor test system in the present invention;

[0047] Figure 4It is a three-dimensional simulation schematic diagram of the flow guiding basin structure in the present invention;

[0048] Figure 5 It is a schematic diagram of different state points of the equal-speed line of the compressor in the present invention;

[0049] Figure 6 It is a schematic diagram for comparing the pressure ratio characteristics of the compressor under different tip hot clearances in the present invention;

[0050] Figure 7 It is a schematic diagram for comparing the efficiency characteristics of the compressor under different tip hot clearances in the present invention. Detailed implementation manners

[0051] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0052] An embodiment of a test method for verifying the influence of the compressor tip clearance on the performance in the present invention. This embodiment is based on Figure 3 The compressor test system shown is used for experiments. As Figure 1 shown, this embodiment specifically includes:

[0053] S1. Construct an input data sequence composed of the inlet temperature and the rotational speed;

[0054] Specifically, convert the inlet temperature and rotational speed corresponding to the compressor under the design condition into the inlet temperature and rotational speed under the sea-level standard atmospheric condition, and construct an input data sequence composed of the inlet temperature and rotational speed based on the temperature and rotational speed under the sea-level standard atmospheric condition.

[0055] Exemplarily, in a specific embodiment, for the inlet temperature T0 and rotational speed N0 corresponding to the compressor under the design condition, convert the inlet temperature T0 and rotational speed N0 to the sea-level standard atmospheric condition. After conversion, the corresponding inlet temperature of the compressor is T1 = 288.15K, and the rotational speed is , and through similarity conversion, ensure the similarity of the internal flow states of the compressor under the two conditions.

[0056] Exemplarily, in a specific embodiment, the steps of constructing an input data sequence composed of the inlet temperature and the rotational speed are as follows: based on the inlet temperature under the sea-level standard atmospheric conditions, increase or decrease the inlet temperature to obtain multiple adjusted temperatures, and obtain the adjusted rotational speed corresponding to each adjusted temperature; based on the inlet temperature under the sea-level standard atmospheric conditions, each adjusted inlet temperature, and the rotational speed corresponding to each inlet temperature as a set of input data, obtain the input data sequence composed of the temperature and the rotational speed.

[0057] That is, based on the inlet temperature T1 = 288.15K, increase or decrease the compressor inlet temperature to Ti, then the adjusted rotational speed The expression is:

[0058]

[0059] In the formula, T1 represents the inlet temperature corresponding to the compressor under the sea-level standard atmospheric conditions; N0 represents the rotational speed corresponding to the compressor under the design conditions; represents the inlet temperature after the th adjustment of the compressor under the sea-level standard atmospheric conditions; represents the rotational speed after the th adjustment of the compressor under the sea-level standard atmospheric conditions.

[0060] Thus, different inlet temperatures (T1, T2, T3, T4... ) and the corresponding rotational speeds (N1, N2, N3, N4... ) can be obtained. Each inlet temperature and the corresponding rotational speed form a set of input data, and multiple sets of input data form an input data sequence.

[0061] S2. Construct a theoretical model of the inlet temperature and the tip hot clearance;

[0062] Specifically, according to each set of input data in the input data sequence, and using the three-dimensional fluid algorithm, thermal analysis algorithm, and finite element calculation method, obtain the radial deformation amount of the rotor blade and the corresponding casing position under each set of input data in the input data sequence; according to the cold clearance between the blade and the casing in the assembled state, combined with the radial deformation amount of the rotor blade and the corresponding casing position under each set of input data, obtain the corresponding theoretical tip hot clearance of the compressor under each set of input data, and construct a theoretical model of the inlet temperature and the tip hot clearance based on the inlet temperature and the corresponding theoretical tip hot clearance of each set of input data.

[0063] Exemplarily, in a specific embodiment, the steps of obtaining the radial deformation amounts of the rotor blades and the corresponding casing positions under each set of input data in the input data sequence are as follows: taking the inlet temperature and rotational speed in each set of input data as input conditions, using a three-dimensional numerical calculation method to obtain the corresponding internal flow field distribution of the compressor under each set of data; and performing a thermal analysis to obtain the corresponding temperature field distributions of the blisk and the compressor casing; based on the internal flow field distribution and the corresponding temperature field distributions of the blisk and the compressor casing, obtaining the radial deformation amounts of the rotor blades and the corresponding casing positions.

[0064] Exemplarily, in a specific embodiment, the steps of obtaining the theoretical tip hot clearance corresponding to the compressor under each set of input data according to the cold clearance between the blades and the casing in the assembled state and the radial deformation amounts of the rotor blades and the corresponding casing positions under each set of input data are as follows:

[0065] According to the cold clearance between the blades and the casing in the assembled state and based on the radial deformation amounts corresponding to the rotor blades and the casing positions under each set of input data, obtaining the theoretical tip hot clearance corresponding to the compressor under each set of input data, that is, the expression of the theoretical tip hot clearance is:

[0066] Δ hot =Δ cold -Δ blade +Δ case

[0067] In the formula, Δ hot represents the theoretical tip hot clearance; Δ cold represents the cold clearance between the blades and the casing; Δ blade represents the radial deformation amount of the rotor blade, and Δ case represents the radial deformation amount of the casing position.

[0068] Exemplarily, in a specific embodiment, the steps of constructing a theoretical model of the inlet temperature and the tip hot clearance are as follows: according to the tip hot clearances (C1, C2, C3, C4...) of the compressor corresponding to different inlet temperatures (T1, T2, T3, T4...), that is, the relationship between the inlet temperature of each set of input data and the corresponding theoretical tip hot clearance, based on this relationship, a theoretical model of the inlet temperature and the tip hot clearance can be constructed to establish a theoretical model of the inlet temperature and the tip hot clearance of the compressor C = f(T), where the range of the tip hot clearance can cover the verified tip hot clearance.

[0069] S3. Obtaining the actual tip hot clearance corresponding to the compressor at the rotational speed of one set of input data among them, and obtaining a correction model;

[0070] Specifically, adjust the temperature at the compressor inlet to the inlet temperature of one set of input data, and push the compressor speed to the speed of this set of input data to obtain the actual tip hot clearance of the compressor under this set of input data; correct the theoretical model according to the difference between the actual tip hot clearance and the theoretical tip hot clearance of the compressor under this set of input data to obtain the corrected correction model.

[0071] Exemplarily, in this embodiment, since the difference between the actual tip hot clearance and the corresponding theoretical tip hot clearance of the compressor under each set of input data is basically unchanged, in order to reduce the calculation amount, one set of input data in the input data sequence is adopted, that is, in this embodiment, according to the i-th set of input data (Ti, Ni) in the input data sequence, use the air intake temperature control system to adjust the inlet temperature of the compressor to the inlet temperature Ti, and then push the compressor speed to the speed Ni, and use the clearance sensor to record the actual tip hot clearance value Ci' of the compressor.

[0072] Exemplarily, in a specific embodiment, correct the theoretical model by combining the deviation value between the actually obtained tip hot clearance Ci' and the theoretically calculated theoretical tip hot clearance Ci in step S2, and then the correction model of the inlet temperature and the tip hot clearance C' = f'(T) can be obtained.

[0073] Thus, the correction model can be obtained.

[0074] S4. Obtain the final inlet temperature and the final speed corresponding to each tip hot clearance to be verified according to the corrected correction model;

[0075] Specifically, input the tip hot clearance to be verified into the correction model to obtain the final inlet temperature corresponding to each tip hot clearance to be verified, and obtain the final speed of the compressor; Exemplarily, input the tip hot clearance Cj' to be verified into the correction model C' = f'(T) to obtain the final inlet temperature Tj corresponding to each tip hot clearance to be verified, and obtain the final speed Nj of the compressor.

[0076] S5. Obtain the actual performance curve of the compressor at the final speed;

[0077] Specifically, detect the tip hot clearance value corresponding to the compressor at the final inlet temperature and the final speed. If the tip hot clearance value is consistent with the tip hot clearance to be verified, obtain the actual performance curve of the compressor at this final speed; if the tip hot clearance value is inconsistent with the tip hot clearance to be verified, adjust the final inlet temperature until the detected tip hot clearance value is consistent with the tip hot clearance to be verified, and obtain the actual performance curve of the compressor when they are consistent.

[0078] Exemplarily, in a specific embodiment, using the intake air temperature control system, first adjust the inlet temperature of the compressor to the final inlet temperature Tj, and then push the compressor speed to the final speed. , according to the tip hot clearance value collected by the clearance sensor at this time. If the collected tip hot clearance is consistent with the tip hot clearance Cj' to be verified, record the performance curve of the compressor at the Nj speed as the actual performance curve; if the collected tip hot clearance is less than the tip hot clearance Cj' to be verified, on the basis of Tj, use the intake air temperature control system to increase the inlet temperature of the compressor. If the measured clearance value is greater than the clearance value Cj' to be verified, on the basis of Tj, use the intake air temperature control system to decrease the inlet temperature of the compressor. Among them, the speed Nj changes with the real 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, record the compressor performance curve as the actual performance curve.

[0079] So far, the actual performance curve of the compressor at the final speed can be obtained.

[0080] S6. Evaluate the influence value of the tip hot clearance on the compressor performance;

[0081] Specifically, evaluate the influence value of the tip hot clearance on the compressor performance according to the actual performance curve and the preset design performance curve. Among them, the influence values include: the influence value of the blocked flow rate, the influence value of the peak efficiency, and the influence value of the surge pressure ratio.

[0082] Exemplarily, in a specific embodiment, the influence value of the blocked flow rate is: the influence value of the blocked flow rate is the flow rate ratio of the blocked flow rate of the actual performance curve and the blocked flow rate of the preset design performance curve; the influence value of the peak efficiency is: the efficiency difference between the peak efficiency of the actual performance curve and the peak efficiency of the preset design performance curve; the influence value of the surge pressure ratio is: the pressure ratio ratio of the surge pressure ratio of the actual performance curve and the surge pressure ratio of the preset design performance curve.

[0083] The following specifically describes this embodiment with reference to the accompanying drawings:

[0084] According to the requirements for compressor development, the following takes the verification of the specific influence values of the compressor performance at the tip hot clearances of 0.25 mm, 0.3 mm, and 0.4 mm as an example for description.

[0085] Such as Figure 3As shown in the figure, the compressor test system includes: an intake air temperature control system, a pressure stabilizing tank, 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 for the compressor test piece through the transmission system; the intake air temperature control system, the pressure stabilizing tank, the compressor test piece, and the exhaust system are connected in sequence to form a gas flow path. The gas enters from the intake air temperature control system, passes through the pressure stabilizing tank and the compressor test piece in sequence, and finally is discharged through the exhaust system. The compressor test piece includes a guide vane basin, an inlet section, a compressor body, and an outlet section. The guide vane basin, the inlet section, the compressor body, and the outlet section are connected in sequence. Among them, as Figure 4 shown, the inlet profile of the guide vane basin is a double-twist line design, followed by a cylindrical section. Small holes with a diameter of 1-2 mm are drilled on the wall of the cylindrical section. The number of small holes is not less than 10 and they are evenly distributed circumferentially. The distance from the tangent point of the double-twist profile and the cylindrical section to the center of the small hole is 0.2 times the diameter of the guide vane basin. A chamber is arranged outside the small hole, and the chamber is connected to the small hole. Four static pressure holes are arranged on the wall of the chamber for measuring the static pressure of the air flow.

[0086] Based on Figure 3 and Figure 4 the compressor test system and the compressor test piece shown, among which, four static pressure measurement holes are arranged on the wall of the chamber in the cylindrical section of the guide vane basin. At the measurement section of the inlet section of the compressor test piece, two five-point comb-shaped total temperature probes and two five-point comb-shaped total pressure probes are respectively arranged. The above-mentioned radial measurement points are all distributed according to equal annulus area. At the measurement section of the outlet section, four three-point comb-shaped total temperature probes and four five-point total pressure probes are arranged, and the radial measurement points are also distributed according to equal annulus area. At the position of the casing corresponding to the compressor rotor blades, three gap sensors are evenly arranged circumferentially to measure the tip hot gap in real time.

[0087] Step 1: Convert the temperature and speed of the compressor under the design condition to the sea-level standard atmospheric condition. After conversion, the corresponding inlet temperature of the compressor is 288.15 K, and the speed is 35200 r / min. Based on the inlet temperature of 288.15 K and the speed of 35200 r / min, an input data sequence composed of the inlet temperature and speed is obtained.

[0088] Step 2: For the input data under the sea-level standard atmospheric conditions, use a three-dimensional fluid simulation calculation tool to obtain the internal flow field distribution at the compressor inlet under the sea-level standard atmospheric conditions. The internal flow field distribution includes: the pressure distribution of the blades and the casing, and the gas temperature and pressure distribution at the air extraction position of the blade disk cavity. On this basis, use a thermal analysis calculation tool to obtain the temperature field distributions of the blade disk and the compressor casing. Taking the internal flow field distribution and the temperature field distribution as inputs, use the finite element calculation method to obtain the radial deformation amounts at the positions of the rotor blades and the corresponding casing. The radial deformation amount of the rotor blade is 0.56 mm, and the radial deformation amount at the casing position is 0.1 mm. At the same time, considering the cold-state clearance between the blade and the casing in the assembled state is 0.77 mm, it can be calculated that under the conditions of an inlet temperature of 288.15 and a rotational speed of 35200 r / min, the theoretical tip hot-state clearance between the rotor blade and the casing is 0.31 mm (0.77 - 0.56 + 0.1).

[0089] Based on the above calculation results and combined with the verification clearance requirements, calculate the theoretical tip hot-state clearances between the compressor rotor blade and the casing under the conditions of inlet temperatures of 248.15 K, 268.15 K, and 298.15 K respectively. To ensure the similarity of the internal flow in the compressor, the rotational speeds corresponding to different inlet temperatures are obtained according to the formula and the rotational speed results are shown in Table 1. The range of the tip hot-state clearance values is 0.22 mm to 0.42 mm, and the required tip hot-state clearance values to be verified (0.25 mm, 0.3 mm, 0.4 mm) are within the above range.

[0090] Table 1

[0091]

[0092] After obtaining the variation law of the inlet temperature and the calculated tip hot-state clearance shown in Table 1, combine with the compressor test system to conduct the verification of the tip hot-state clearance under the condition of an inlet temperature of 288.15 K. Use the air intake temperature control system to adjust the temperature at the compressor inlet to 288.15 K, and then gradually push the rotational speed of the compressor to 35200 r / min by adjusting the power system. By adjusting the opening degree of the exhaust throttle valve, record different state points of the compressor at this rotational speed in sequence. The state points should at least include the block point, the design point, the peak efficiency point, and the surge point. Use the static pressure measurement points of the guide basin and the probe measurement points of the measurement sections at the inlet and outlet sections to obtain the flow rate, pressure ratio, and efficiency of the compressor at each state point (i.e., the block point and the surge point), so as to obtain the pressure ratio characteristics and the efficiency characteristics. At the same time, obtain the measured hot-state clearance value according to the clearance sensor. The hot-state clearance value at this time is 0.3 mm, as Figure 5 shown Figure 5 shows the schematic diagram of different state points of the constant rotational speed line of the compressor Figure 6 and is the schematic diagram of the pressure ratio characteristics of the compressorFigure 7 It is a schematic diagram of the efficiency characteristics of the compressor.

[0093] Considering that under the condition that the inlet temperature is 288.15 K, the calculated theoretical hot tip clearance value is 0.31 mm, and the deviation between the two is 0.01 mm. That is, in this embodiment, it is considered that the calculated theoretical hot tip clearance value is larger than the measured actual hot tip clearance value, and the large deviation is 0.01 mm. Therefore, subtracting this deviation amount from the hot tip clearances corresponding to other inlet temperatures respectively, the corrected hot tip clearances as shown in Table 2 can be obtained.

[0094] Table 2

[0095]

[0096] For the required hot tip clearances to be verified, 0.25 mm and 0.4 mm, combined with the relationship between the inlet temperature and the corrected hot tip clearance, linear interpolation can be used to calculate the corresponding inlet temperatures as 299.3 K and 253.9 K. Considering that the change range of the tip clearance value is not large, linear interpolation can be used for calculation. If the clearance change range is large, polynomial or B-spline interpolation can be used for processing. At the same time, using the rotational speed conversion formula the final rotational speeds corresponding to the final inlet temperatures of 299.3 K and 253.9 K are 35874.6 r / min and 33041.9 r / min respectively.

[0097] Verify the two hot tip clearances at the above-mentioned final inlet temperatures of 299.3 K and 253.9 K and the corresponding final rotational speeds of 35874.6 r / min and 33041.9 r / min respectively:

[0098] First, use the intake air temperature control system to adjust the inlet temperature to the final inlet temperature of 299.3 K, and push the rotational speed to the final rotational speed of 35874.6 r / min. At this time, the actual hot tip clearance measured by the clearance sensor is 0.24 mm. Use the intake air temperature control system to appropriately reduce the inlet temperature by 1.5 K, and the rotational speed decreases accordingly according to the result of the conversion formula. At this time, the hot tip clearance is 0.25 mm, which is consistent with the verified clearance value. Then fix the inlet temperature and the corresponding rotational speed, adjust the opening of the exhaust throttle valve, and record the performance characteristics of different state points of the compressor at the same rotational speed in turn, and the actual performance curve can be obtained. The steps for the hot tip clearance of 0.4 mm and the verified hot tip clearance of 0.25 mm are the same, and this embodiment will not be elaborated.

[0099] Through the adjustment of the inlet temperature, the actual performance curves of the compressor hot tip clearances of 0.25 mm, 0.3 mm, and 0.4 mm respectively and the corresponding design performance curves when the preset compressor hot tip clearances are 0.25 mm, 0.3 mm, and 0.4 mm are obtained. Based onFigure 6 and Figure 7 As shown in Figure 7 , the preset design performance curve is compared with the actual performance curve to obtain the influence value of the tip hot clearance on the compressor as shown in Table 3. Through comparative analysis, it can be concluded that as the hot clearance increases from 0.25 mm to 0.4 mm, the compressor flow rate decreases by 1.2%, the peak efficiency decreases by 0.5 percentage points, and the surge point pressure ratio decreases by 2.5%.

[0100] Table 3

[0101]

[0102] It should be noted that in this embodiment, the tip hot clearance of 0.25 mm is used as the reference state, and the states of the other tip hot clearances are compared with the reference state.

[0103] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within 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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