Low speed simulation method and device for coupling compressor s-shaped transition section and stator

Abstract

The present disclosure provides a compressor S-shaped transition section and stator coupling low-speed simulation method and device, wherein the compressor S-shaped transition section and stator coupling low-speed simulation method comprises: S1. low-speed simulation design is carried out on the transition section flow channel containing a stator; S2. low-speed simulation design is carried out on the two-dimensional blade profile of the stator in the transition section containing the stator; S3. after the two-dimensional blade profile of the stator is stacked, the low-speed simulation of the meridian flow field of the transition section containing the stator is converted; S4. according to the actual flow field after the stator, the flow channel of the transition section after the stator is adjusted, and the low-speed simulation of the compressor S-shaped transition section and the stator coupling is completed. The low-speed simulation device is prepared based on the simulation design of the above low-speed simulation method. By using the compressor S-shaped transition section and stator coupling low-speed simulation method and device of the present disclosure, the similarity between the internal flow field of the transition section containing the stator and the high-speed prototype is significantly improved, so that the low-speed simulation can better reflect the flow field characteristics of the high-speed prototype, and the simulation accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of low-speed simulation of compressors, in particular to a low-speed simulation method and device for coupling an S-shaped transition section of a compressor with a stator. BACKGROUND

[0002] A compressor is an important component in an aero-engine, and accurate measurement of the internal flow field of the compressor is very important for understanding the internal flow mechanism of the compressor. Due to high rotation speed, small size of the real compressor, and high cost of high-speed experiments, countries around the world often use low-speed simulation methods to measure the internal flow field of the compressor. The transition section of the compressor is an important component connecting the low-pressure compressor and the high-pressure compressor in the compressor. As the load of the compressor increases, the radial difference between the high-pressure compressor and the low-pressure compressor becomes larger and larger, and the outlet stator of the low-pressure compressor is often placed in the lower pressure flow path in the front part of the transition section.

[0003] Low-speed simulation design is not a design according to design indicators, using the same design parameters as high speed, and re-designing at low speed. The essence of low-speed simulation design is not design, but similarity conversion of the high-speed prototype. That is, the internal flow field of the high-speed compressor is restored through the low-speed, large-size model compressor, the internal flow field of the low-speed simulation compressor is measured, the internal flow mechanism is found out, and the low-speed simulation compressor is improved. After experimental verification, the high-speed compressor can be improved according to the corresponding similarity criterion.

[0004] In the existing low-speed simulation design method, the low-speed simulation of the transition section and the internal stator thereof is often carried out separately, and the low-speed simulation design of the transition section often adopts a direct geometric magnification method, which will make the internal flow field of the high-low speed transition section differ greatly, and cannot well reflect the flow field characteristics in the high-speed transition section, affecting the accuracy of the simulation. SUMMARY

[0005] In order to solve the problem that the low-speed simulation of the transition section and the internal stator thereof in the prior art cannot well reflect the flow field characteristics in the high-speed transition section, the present disclosure provides a low-speed simulation method for coupling an S-shaped transition section of a compressor with a stator, comprising:

[0006] low-speed simulation design of the flow passage of the transition section with a stator;

[0007] low-speed simulation design of the two-dimensional blade profile of the stator in the transition section with a stator;

[0008] low-speed simulation conversion of the meridian flow field of the transition section with a stator after stacking the two-dimensional blade profile of the stator;

[0009] According to the actual flow field behind the stator, the flow passage of the transition section behind the stator is adjusted, and the coupling of the S-shaped transition section of the compressor and the stator is simulated at low speed.

[0010] By using the method for simulating the coupling of the S-shaped transition section of the compressor and the stator at low speed, the similarity between the internal flow field of the transition section containing the stator and the high-speed prototype is significantly improved, so that the low-speed simulation can better reflect the flow field characteristics of the high-speed prototype, and the simulation accuracy is improved.

[0011] The example of the disclosure provides a similarity criterion that needs to be ensured when a low-speed simulation design is performed on the flow passage of the transition section containing the stator, including: Reynolds number, ratio ΔR / L of inlet and outlet diameter difference and length, ratio Hin / L of inlet height and length, wall non-dimensional isentropic velocity ratio V / V1 distribution, and hub ratio. Compared with the low-speed transition section that is geometrically scaled according to the prior art, the difference between the total pressure loss coefficients of the high-speed and low-speed transition sections is significantly reduced after the low-speed simulation design is performed by using the method provided by the disclosure.

[0012] The example of the disclosure provides a method for ensuring the similarity of the wall non-dimensional isentropic velocity ratio V / V1 distribution, that is, by adjusting the internal area of the low-speed simulation transition section, the wall non-dimensional isentropic velocity ratio V / V1 distributions of the high-speed flow passage and the low-speed flow passage are made the same.

[0013] The example of the disclosure provides a similarity criterion that needs to be ensured when a low-speed simulation design is performed on the two-dimensional blade profile of the stator in the transition section containing the stator, including: solidity, D factor, Reynolds number, and blade surface non-dimensional isentropic velocity distribution. The Reynolds number is greater than the self-modification Reynolds number. When the method of the disclosure is used, the low-speed simulation blade profile has good similarity with the high-speed blade profile from the design state to the stall state and the state of small negative attack angle, and the low-speed blade profile cannot well simulate the flow of the high-speed blade profile at a large negative attack angle. However, considering the actual working condition of the compressor, the working point is mainly between the small negative attack angle and the near stall point, so the low-speed simulation of the disclosure can meet the needs of actual engineering.

[0014] The example of the disclosure provides a condition that should be met when the two-dimensional blade profile of the stator is stacked, including:

[0015] 1) The important inlet boundary conditions of the high-speed and low-speed transition sections are similar, and these boundary conditions should include the total pressure distribution, flow distribution, and inlet flow angle distribution of the inlet;

[0016] 2) After stacking, the incoming flow attack angle state of each low-speed stator section is checked, and the incoming flow attack angle of each stator section is adjusted to be consistent with the high-speed prototype;

[0017] 3) The outlet geometric angle of the low-speed stator is adjusted so that the outlet flow angle of the low-speed stator is consistent with the high-speed prototype;

[0018] 4) Adjust the low-speed stator inlet geometry angle and the low-speed incoming airflow angle, and ensure that the high-speed and low-speed stators have the same incoming flow angle, so that the D factor is consistent with the high-speed prototype.

[0019] By using this method, the three-dimensional flow field under low-speed conditions has higher consistency compared with the high-speed prototype, and the accuracy of low-speed simulation is improved.

[0020] The adjustment method provided by the present disclosure adjusts the flow passage of the transition section behind the stator according to the actual flow field behind the stator, that is, adjusting the area of the flow passage behind the stator so that the dimensionless isentropic velocity ratio V / V1 of the wall surface of the flow field behind the stator is the same. By using this method, the S2 flow field at the outlet of the transition section has higher consistency compared with the high-speed prototype, and the accuracy of low-speed simulation is further improved.

[0021] The present disclosure also provides a low-speed simulation device for coupling a compressor S-shaped transition section and a stator, which is designed and prepared based on the above-mentioned low-speed simulation design method for coupling a compressor S-shaped transition section and a stator.

[0022] The present disclosure provides a low-speed simulation device for coupling a compressor S-shaped transition section and a stator, which is designed and prepared based on the above-mentioned low-speed simulation design method for coupling a compressor S-shaped transition section and a stator.

[0023] The present disclosure has at least one of the following advantages:

[0024] 1. By using the low-speed simulation method for coupling a compressor S-shaped transition section and a stator provided by the present disclosure, the similarity between the internal flow field of the transition section containing a stator and the high-speed prototype is significantly improved, so that the low-speed simulation can better reflect the flow field characteristics of the high-speed prototype, and the accuracy of simulation is improved.

[0025] 2. Compared with the low-speed transition section designed by using the geometric scaling method of the prior art, the difference in total pressure loss coefficient between the high-speed and low-speed transition sections is significantly reduced after the low-speed simulation design by using the method provided by the present disclosure.

[0026] 3. When the method provided by the present disclosure is used, the low-speed simulation blade profile has good similarity with the high-speed blade profile in the design state to the stall state and in the small negative attack angle state. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The flowchart of the low-speed simulation method of the present disclosure is shown.

[0028] Figure 2 The meridian flow surface diagram of the transition section containing a stator is shown.

[0029] Figure 3The ratio of the area of any point of the high-low speed transition section to the area of the inlet along the flow direction and the comparison chart of the transition section geometry.

[0030] Figure 4 The total pressure loss coefficient of the high-low speed transition section.

[0031] Figure 5 The high-low speed blade profile comparison chart.

[0032] Figure 6 The high-low speed blade profile angle of attack-loss characteristic (left) and angle of attack-lag angle characteristic (right) comparison chart.

[0033] Figure 7 The transition section S2 flow field parameter chart obtained by low speed simulation.

[0034] Figure 8 The transition section three-dimensional flow field obtained by low speed simulation and the high speed prototype comparison chart.

[0035] Figure 9 The transition section outlet main parameter distribution chart along the span obtained by low speed simulation.

[0036] Figure 10 The transition section total pressure loss characteristic obtained by low speed simulation and the high speed prototype comparison chart.

[0037] Figure 11 The high-low speed transition section stator three-dimensional flow field comparison chart under typical working conditions.

[0038] Figure 12 The dimensionless isentropic velocity ratio-dimensionless axial position schematic diagram of the low speed simulation design using the transition section and the stator and the method of the present disclosure.

[0039] Figure 13 The velocity / inlet velocity-dimensionless axial position schematic diagram of the low speed simulation design using the transition section and the stator and the method of the present disclosure. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and technical effects to be solved by the present disclosure clearer and more apparent, the technical solutions of the present disclosure are described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and not to limit the present disclosure.

[0041] Embodiment 1

[0042] Figure 2 The schematic diagram of a certain transition section with a stator is shown, which is converted by the low speed simulation design method of the S-shaped transition section and stator coupling of the compressor of the present disclosure shown in Figure 1 ​

[0043] S1. Designing the stator-containing transition section flow passage by low-speed simulation.

[0044] When performing step S1 of low-speed simulation design, the existing low-speed simulation conversion method (such as the low-speed simulation conversion method in the low-speed simulation of maximum thickness of blade profile, Liu Baojie et al., Journal of Engineering Thermophysics, 2021, No. 3) is used to convert the high-speed prototype containing the stator transition section flow passage into a low-speed simulation design. The similarity criteria that need to be ensured during the conversion include: Reynolds number, ratio of inlet-outlet diameter difference to length ΔR / L, ratio of inlet height to length Hin / L, wall non-dimensional isentropic velocity ratio V / V1 distribution, and hub ratio. The method for ensuring the similarity of the wall non-dimensional isentropic velocity ratio V / V1 distribution is to adjust the internal area of the low-speed simulation transition section, so that the wall non-dimensional isentropic velocity ratio V / V1 distribution of the high-speed flow passage is the same as that of the low-speed flow passage.

[0045] When the high-speed prototype is converted into a low-speed simulation based on the similarity criteria of the present disclosure, the distribution of the ratio of the area of any point in the high-low speed transition section to the inlet area along the flow direction and the comparison of the geometry of the high-low speed transition section can be obtained, as shown in Figure 3 Since the high-speed prototype transition section is expanding in the front half, it should expand more severely under low-speed conditions to compensate for the impact of different compressibilities. And since the high-speed prototype transition section is converging in the back half, it should converge more severely under low-speed conditions to compensate for the impact of different compressibilities.

[0046] Figure 4 The total pressure loss coefficients of the transition section inlet and outlet under low-speed simulation, geometric scaling simulation, and high-speed prototype conditions are compared. As can be seen from Figure 4 Compared with the low-speed transition section of the geometric scaling simulation, the error value of the total pressure loss coefficient of the low-speed simulation design method of the present disclosure compared with the high-speed prototype is reduced from 10.9% of the geometric scaling simulation to 2.7% after using the low-speed simulation design method of the present disclosure. The error value calculation method is: W = [1-W1 / W0]*100%, where W is the error value, W1 is the total pressure loss coefficient during simulation, and W0 is the total pressure loss coefficient of the high-speed prototype. It can be seen that, compared with the existing geometric scaling simulation method, the low-speed simulation design method of the present disclosure can make the simulation value closer to the high-speed prototype, thereby improving the accuracy of the simulation.

[0047] S2. Designing the stator-containing transition section inner stator two-dimensional blade profile by low-speed simulation.

[0048] In the step S2, the low-speed simulation design is performed. The low-speed simulation design is performed on the two-dimensional blade profile of the stator in the high-speed prototype by using the existing low-speed simulation conversion method. The similarity criteria to be ensured in the conversion include the solidity, the D factor, the Reynolds number and the blade surface non-dimensional isentropic velocity distribution. The Reynolds number is greater than the self-modeling Reynolds number. The self-modeling Reynolds number is a set value, for example, 200000. When the Reynolds number is greater than the self-modeling Reynolds number, the self-modeling region is entered.

[0049] Figure 5 The comparison results of the low-speed simulation blade profile and the high-speed prototype blade profile are given (using the chord non-dimension). Figure 5 It can be seen that the inlet flow angle of the low-speed simulation blade profile is increased compared with the inlet flow angle of the high-speed blade profile under the condition that the outlet flow angle is unchanged. Compared with the high-speed blade profile, the low-speed blade profile has the following changes in the blade profile parameters: (1) the leading edge radius is increased; (2) the maximum thickness of the blade profile is slightly increased; (3) the blade profile bending angle is increased. In addition, the loading form of the blade is also changed, that is, the loading is slightly moved forward.

[0050] Figure 6 The comparison of the angle of attack-loss characteristics and the angle of attack-lag angle characteristics of the high-speed blade profile and the low-speed simulation blade profile is given. It can be seen from the analysis of the angle of attack-loss characteristics that the total pressure loss of the high-speed blade profile is basically the same as that of the low-speed simulation blade profile in the positive attack angle state, and the available attack angle range is basically the same. In the negative attack angle state, the available attack angle range of the low-speed simulation blade profile is obviously greater than that of the high-speed blade profile. This is because the blade profile does not have the blockage problem at the low Mach number, and the negative attack angle state is not easy to separate, so that the negative attack angle range is large. Thus, it is also explained that the low-speed simulation blade profile has good similarity with the high-speed blade profile in the design state to the stall state and the small negative attack angle state. In the large negative attack angle state, the low-speed simulation blade profile cannot well simulate the flow of the high-speed blade profile. This problem can also be explained from the angle of attack-loss characteristics. However, considering the actual working condition of the compressor, the working point is mainly between the small negative attack angle and the near stall point, so the low-speed simulation can meet the needs of the actual engineering.

[0051] S3. The two-dimensional blade profile of the stator is stacked to simulate the low-speed simulation of the meridian flow field of the stator transition section.

[0052] When stacking the two-dimensional stator blade profiles, the following should be met: 1) The important inlet boundary conditions of the high-speed and low-speed transition sections are similar, and these edge strips should include the total pressure distribution, flow distribution, and inlet airflow angle distribution of the inlet; 2) After stacking, check the incoming flow angle state of each low-speed stator section, and adjust the incoming flow angle of each stator section to be consistent with the high-speed prototype; 3) Adjust the low-speed stator outlet geometric angle so that the low-speed stator outlet airflow angle is consistent with the high-speed prototype; 4) Adjust the low-speed stator inlet geometric angle and the low-speed incoming flow airflow angle, and make the D factor consistent with the high-speed prototype while ensuring that the high-speed and low-speed stators have the same incoming flow angle.

[0053] After the above adjustments, Figure 7 The basic parameters for measuring the performance of the stator, such as the D factor, the total pressure loss coefficient, and the density-flow ratio along the spanwise distribution are compared with the high-speed prototype. It can be seen that the above parameters coincide well with the results of the high-speed prototype. Therefore, the results of the three-dimensional flow field at low speed are also consistent with those of the high-speed prototype. Figure 8 shown.

[0054] S4. Adjust the flow path of the stator transition section based on the actual flow field behind the stator to complete the low-speed simulation of the coupled S-shaped transition section of the compressor and the stator. The adjustment method is to adjust the area of ​​the flow path behind the stator to ensure the same distribution of the dimensionless isentropic velocity ratio V / V1 on the wall of the flow field behind the stator.

[0055] The comparison between the spanwise distribution of the main parameters of the transition section outlet obtained by the final adjustment and the high-speed prototype is shown in the figure. Figure 9 As shown, it can be seen that the S2 flow field at the transition section outlet obtained is also highly similar to that of the high-speed prototype.

[0056] The final low-speed simulation results show that the total pressure loss of the stator transition section changes with the incoming flow angle, which is compared with the high-speed prototype. Figure 10 As shown. Figure 10 It can be seen that the stator loss obtained by the low-speed simulation is slightly larger than that of the high-speed prototype at small angles of attack, and its development trend with angle of attack is basically consistent with that of the high-speed prototype; and the loss from the stator outlet to the transition section outlet obtained by the low-speed simulation is basically consistent with that of the high-speed prototype under all working conditions; thus, the development trend of the total loss of the transition section in the low-speed simulation is also consistent with that of the high-speed prototype. Figure 11 The comparison of the stator three-dimensional flow field in the high-speed and low-speed transition sections under typical working conditions is given. Figure 11 It can also be seen that the flow fields at high and low speeds have good similarities.

[0057] also, Figure 10 The figure also gives the variation of the total pressure loss coefficient of each part with the incoming flow angle when the stator is simulated at low speed but the transition section flow channel is not adjusted. Figure 10It can be seen that in this case, due to the fact that the flow passage of the transition section does not undergo low-speed conversion, the total pressure loss coefficient from the stator outlet to the transition section outlet deviates greatly from that of the high-speed prototype; moreover, although the stator characteristics near the design point are not much different from the above-mentioned low-speed simulation results, the stator characteristics have already deviated when the stator is in a large angle of attack state, which is mainly caused by the potential effect of the rear flow field; the resulting total loss characteristics of the transition section also differ greatly from those of the high-speed prototype. Therefore, when designing a low-speed simulation of a transition section containing a stator blade, it is necessary to convert the low-speed simulation of the transition section flow passage, and both the low-speed simulation design of the flow passage and the low-speed simulation design of the stator blade must be considered in order to make the low-speed flow field similar to the high-speed flow field.

[0058] Example 2

[0059] Figure 2 is a schematic diagram of a certain stator-containing transition section, and the transition section is designed separately by low-speed simulation, and the stator is designed separately by low-speed simulation. The results are shown in Figure 12 and Figure 13 The prior art usually separately simulates the transition section and the stator by low-speed simulation and then fits to obtain a low-speed simulation model of the stator-containing transition section. Compared with the prior art, the similarity of the flow field behind the stator is greatly improved after the method of the present disclosure is used, and it can be seen that the simulation accuracy of the low-speed simulation model can be significantly improved by using the method of the present disclosure.

[0060] Example 3

[0061] A compressor S-shaped transition section and stator coupling low-speed simulation device, the device is designed based on the above-mentioned compressor S-shaped transition section and stator coupling low-speed simulation design method for the high-speed prototype, and is prepared by using 3D printing technology. The device has high simulation accuracy, the difference between the high-speed and low-speed transition section total pressure loss coefficients is small, and the low-speed simulation blade profile has high similarity to the high-speed blade profile in the design state to the stall state and the small negative angle of attack state, and can be used as a low-speed model to accurately simulate the flow field state of the high-speed prototype.

[0062] Although embodiments of the present disclosure have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made without departing from the principles and spirit of the present disclosure, and the scope of the present disclosure is defined by the appended claims and their equivalents.

Claims

1. The low-speed simulation method of the S-shaped transition section and stator coupling of the compressor is characterized by: include: Conduct low-speed simulation design of the flow passage including the stator transition section; Conduct low-speed simulation design of the stator two-dimensional blade profile including the stator transition section; After stacking the two-dimensional stator blade profile, the low-speed simulation conversion of the meridional flow field including the stator transition section is carried out; when stacking the two-dimensional stator blade profile, the following conditions should be met: The important inlet boundary conditions of the high-speed and low-speed transition sections are similar. These edge strips should include the distribution of the total pressure, flow rate and inlet flow angle at the inlet. After stacking, check the incoming flow angle of attack of each low-speed stator section and adjust the incoming flow angle of attack of each stator section to be consistent with the high-speed prototype; Adjust the low-speed stator outlet geometry angle so that the low-speed stator outlet airflow angle is consistent with the high-speed prototype; Adjust the low-speed stator inlet geometry and low-speed incoming flow angle to ensure that the high-speed and low-speed stators have the same incoming flow angle of attack, so that the D factor is consistent with the high-speed prototype; The flow channel of the transition section behind the stator is adjusted according to the actual flow field behind the stator to complete the low-speed simulation of the coupling between the S-shaped transition section of the compressor and the stator; when the flow channel of the transition section behind the stator is adjusted according to the actual flow field behind the stator, the adjustment method is: adjusting the area of ​​the flow channel behind the stator so that the dimensionless isentropic velocity ratio V / V1 of the wall surface of the flow field behind the stator is the same.

2. The low-speed simulation method for coupling the compressor S-shaped transition section and the stator according to claim 1 is characterized in that: When performing low-speed simulation design on the flow channel containing the stator transition section, the similarity criteria that need to be ensured include: Reynolds number, the ratio of the inlet and outlet diameter difference to the length ΔR / L, the ratio of the inlet height to the length Hin / L, the wall dimensionless isentropic velocity ratio V / V1 distribution, and the hub ratio.

3. The low-speed simulation method for coupling the compressor S-shaped transition section and the stator according to claim 2 is characterized in that: The method to ensure the similarity of the distribution of the dimensionless isentropic velocity ratio V / V1 of the wall surface is as follows: by adjusting the internal area of ​​the low-speed simulation transition section, the dimensionless isentropic velocity ratio V / V1 distribution of the high-speed flow channel wall and the low-speed flow channel wall is the same.

4. The low-speed simulation method for coupling the compressor S-shaped transition section and the stator according to claim 1 is characterized in that: When performing low-speed simulation design on the two-dimensional stator blade profile in the stator transition section, the similarity criteria that need to be ensured include: consistency, D factor, Reynolds number and dimensionless isentropic velocity distribution on the blade surface, among which the Reynolds number is greater than the self-modeling Reynolds number.

5. A low-speed simulation device for coupling an S-shaped transition section of a compressor with a stator, characterized in that: For the high-speed prototype, based on the low-speed simulation method of the compressor S-shaped transition section and stator coupling as described in any one of claims 1-4, the compressor S-shaped transition section and stator coupling low-speed simulation device is designed and prepared.

6. The low-speed simulation device for coupling an S-shaped transition section of a compressor with a stator according to claim 5, characterized in that: After preparing the model based on the low-speed simulation design, the compressor S-shaped transition section and stator coupling low-speed simulation device is prepared using 3D printing technology.

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