A method for identifying pulsation-sensitive key stages of a multi-stage compressor
Patent Information
- Application Number
- CN202611004623.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-07
- Publication Date
- 2026-11-03
AI Technical Summary
Existing technologies lack methods to identify the stage most sensitive to pulsating back pressure in multi-stage compressors, making it difficult for designers to determine which stage is most prone to performance degradation under pulsating back pressure and to identify the key stages for optimization.
An unsteady numerical calculation model of a multi-stage compressor was established. A pulsating back pressure boundary condition with a set frequency and amplitude was applied. The static pressure time series was recorded, and the influence of the natural frequency component was eliminated. By comparing the flow field response feature set, the pulsation-sensitive key stage was determined and optimized.
The system identifies critical stages in multi-stage compressors that are sensitive to pulsation, provides judgment criteria, accurately locates and optimizes key stages, reduces design and testing workload, improves anti-pulsation capability and operational reliability, and controls R&D costs.
Smart Images
Figure CN123028158A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aero-engine design technology, and more specifically to a method for identifying the critical stage in a multi-stage compressor that is most sensitive to pulsating back pressure. Background Technology
[0002] When a multi-stage compressor is subjected to downstream pulsating back pressure, the pressure pulsation propagates and attenuates from the outlet upstream. Due to differences in blade profile, load, radial clearance, inlet conditions, and operating point location at each stage, the response intensity of different stages to the same pulsating back pressure varies. Some stages can dissipate pulsating energy relatively quickly, while others are more prone to phenomena such as an expansion of the low-energy fluid range at the blade tip, enhanced local separation, or a decrease in stability margin. These sensitive stages often limit the upper limit of the pulsation amplitude that the entire compressor can withstand and are the key stages that need to be identified and optimized first in the anti-pulsation design of multi-stage compressors.
[0003] Current compressor optimization methods often focus on overall or single-stage performance, lacking procedures and criteria for identifying vulnerable stages based on the intensity of pulsation response in multi-stage environments. Designers struggle to determine which stage is most susceptible to performance degradation under pulsating back pressure, and also find it difficult to prioritize local optimization efforts for that stage. Therefore, a method is needed that can first determine the range of pulsation impact, then compare the flow field response intensity of affected stages, and finally output the pulsation-sensitive critical stage. Summary of the Invention
[0004] In view of this, the present invention provides a method for identifying critical stages sensitive to pulsation in multi-stage compressors, which solves the problems of lacking critical stage identification procedures and judgment criteria in the prior art and the difficulty in determining the key stages for anti-pulsation optimization.
[0005] This invention is achieved using the following technical solution: An unsteady numerical model of the multi-stage compressor under test is established, and a pulsating back pressure boundary condition with a set frequency and amplitude is applied at the compressor outlet. In the formula, Instantaneous outlet back pressure / kPa; Average back pressure / kPa; The amplitude of the fluctuation is expressed in kPa. f The pulse frequency is expressed in Hz. t Time (in seconds).
[0006] The static pressure time series at the inlet and outlet interfaces of each stage were recorded within multiple stable pulsation cycles. The fluctuation amplitude corresponding to the frequency of the pulsating back pressure was extracted, and the influence of the compressor's natural frequency component was eliminated. Based on the attenuation data of the pulsating back pressure along the axial direction and the complete dissipation criterion, the farthest stage to which the pulsating back pressure could effectively propagate was determined. The complete dissipation criterion was: when the relative amplitude of the static pressure pulsation was lower than a preset dissipation threshold of 0.5%, the pulsating back pressure was considered to have been completely dissipated at that location, and the effective influence range of the pulsating back pressure was the blade row corresponding to that location and the range thereafter. Subsequent sensitivity comparisons were only conducted on the affected stages within this range.
[0007] For each affected level, a high-entropy cloud map of 95% of the compressor blades is extracted within a pulsating cycle, and the fluctuation amplitude of the low-energy fluid coverage area at the blade tip is recorded to form a flow field response feature set for comparing the sensitivity of each level.
[0008] By comparing the fluctuations in the low-energy fluid region at the blade tip of each effective influence level, the level with the largest fluctuation amplitude in the low-energy fluid region coverage area is determined as the pulsation-sensitive key level.
[0009] As the critical stage sensitive to compressor pulsation, this stage should be prioritized for optimization in compressor anti-pulsation design.
[0010] Compared with the prior art, the present invention has at least the following beneficial technical effects: This invention provides a method for systematically identifying pulsation-sensitive key stages of a multi-stage compressor. By establishing a correlation model between flow field characteristics and pulsation characteristics, the most pulsation-sensitive stages are selected from numerous compressor stages, laying a solid foundation for subsequent targeted analysis.
[0011] The criteria for determining critical levels are given, which makes the determination process highly operable and consistent, and avoids subjective bias caused by experience-based judgment.
[0012] It can accurately pinpoint the key levels of design optimization, avoiding resource waste. By focusing the optimization scope on a few critical levels, it significantly reduces the workload of design and testing, effectively controlling R&D costs and cycles while improving the improvement effect.
[0013] To provide a scientific basis for improving the overall compressor's anti-pulsation capability, based on the precise identification of key components, the core links affecting the overall stability of the compressor can be identified from the source, supporting targeted structural optimization and flow field control, thereby systematically enhancing the compressor's anti-pulsation capability and operational reliability.
[0014] This method has good versatility and is applicable to axial compressors of different models, stages, and operating conditions. Attached Figure Description
[0015] Figure 1This is a schematic diagram of a 10.5-stage axial compressor for a certain type of hydrogen-fired turbine engine in an embodiment of the present invention.
[0016] Figure 2 This is a diagram showing the attenuation pattern of 7% pulsating back pressure between stages in an embodiment of the present invention.
[0017] Figure 3 This is a comparison diagram of the entropy cloud map of the flow field at the tip of the last six stages in an embodiment of the present invention.
[0018] Figure 4 This is a complete technical roadmap for the present invention. Detailed Implementation
[0019] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.
[0020] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention.
[0021] The critical stage of the 10.5-stage axial compressor of a certain type of hydrogen-fired turbine engine was identified for pulsation sensitivity. Some of its design parameters are shown in Table 1 below.
[0022] Table 1 Design parameters of a 10.5-stage axial compressor for a certain type of hydrogen-fired turbine engine Unsteady numerical simulations were performed on the multi-stage compressor, with the pulsating back pressure frequency set to 400 Hz, the relative pulsation amplitude of the back pressure to 7%, and the dynamic boundary conditions for the pulsating back pressure as follows: .
[0023] The fluctuation amplitude corresponding to the frequency of pulsating back pressure was extracted to determine the stage number corresponding to a static pressure relative pulsation amplitude lower than a preset dissipation threshold of 0.5%. Under a 7% pulsation amplitude condition, the pulsating back pressure could affect the vicinity of the fifth-stage rotor; therefore, the last six stages were selected as the focus of analysis. The entropy distribution of the last six stages at 95% blade height was extracted, and the fluctuation of the low-energy fluid region at the blade tip of each stage in the last six stages was compared. The seventh stage was determined to be the stage with the largest fluctuation amplitude in the low-energy fluid region coverage area.
[0024] Therefore, the seventh stage rotor was identified as the pulsation-sensitive critical stage of this multi-stage compressor.
[0025] For the seventh-stage rotor, a key anti-pulsation design can be implemented by optimizing the blade profile and load distribution, improving inlet matching conditions, enhancing blade tip anti-separation capability, or installing casing treatment, damping structure or flow control structure near the seventh stage.
[0026] The reason why the seventh stage is a critical stage is that: this stage is located in the pulsation propagation path where the pulsation energy has not completely decayed and can still be subject to significant back pressure disturbance; at the same time, the blade load of this stage is high, the low-energy fluid region at the blade tip is sensitive to changes in back pressure, and there is a strong interaction between the flow in the blade tip gap and the pulsating back pressure.
[0027] The above description is a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention.
Claims
1. A method for identifying a pulsation-sensitive critical stage in a multi-stage compressor, characterized in that, Includes the following steps: An unsteady numerical calculation model of the multi-stage compressor under test is established, and a pulsating back pressure boundary condition with a set frequency and a set amplitude is applied at the compressor outlet. Extract the static pressure time series at each inlet and outlet interface to obtain the attenuation data of the pulsating back pressure propagating axially in the multi-stage compressor, and determine the effective influence level range of the pulsating back pressure based on the complete dissipation criterion. Within the effective influence level range, extract the blade tip entropy cloud map of the compressor under test within one cycle and record the fluctuation of the low-energy fluid region at the blade tip. By comparing the fluctuations in the low-energy fluid region at the blade tip of each effective influence level, the level with the largest fluctuation amplitude in the low-energy fluid region coverage area is determined as the pulsation-sensitive key level. Output the pulse-sensitive critical level.
2. The method according to claim 1, characterized in that, The unsteady numerical simulation uses a single-frequency sinusoidal wave-like pulsating back pressure: In the formula, Instantaneous outlet back pressure / kPa; Average back pressure / kPa; The amplitude of the fluctuation is expressed in kPa. f The pulse frequency is expressed in Hz. t Time (in seconds).
3. The method according to claim 1, characterized in that, The complete dissipation criterion is as follows: when the relative amplitude of static pressure pulsation is lower than the preset dissipation threshold of 0.5%, it is considered that the pulsating back pressure has been completely dissipated at that position, and the effective influence range of the pulsating back pressure is the corresponding leaf row and the range thereafter.
4. The method according to claim 1, characterized in that, The blade tip entropy cloud map was extracted from the unsteady numerical simulation results, with the extraction location being the 95% blade height section. The entropy value was calculated from the static temperature, static pressure, and density in the flow field.
5. The method according to any one of claims 1-4, characterized in that, This method is applicable to axial flow compressors of different models, stages, and operating conditions.