Compressor system and method for realizing stable boundary control of gas compressor

Abstract

The invention discloses a compressor system and a method for realizing stable boundary control of a gas compressor thereof, which can actively adjust parameters B of the system and realize switching of an instability mode of the gas compressor between surging and rotating stall by only depending on an independent, small and adjustable switching section on the premise of not modifying large basic hardware (such as a volute and a pipeline). According to the principle of the compressor system provided by the embodiment of the invention, the effective flow area is changed by adjusting the angle of the turbine guider, so that the stability boundary of an upstream gas compressor or a fan is actively expanded, low-cost and rapid adjustment of the stability of the gas compressor is realized, the research and development efficiency is improved, and the test period is effectively shortened. The compressor system provided by the embodiment of the invention has the characteristic of wide applicability, can be applied to an independent compression system part test environment, and can also be applied to a complex complete machine environment comprising a compression system.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of aero-engine technology, and in particular to a compressor system and a method for achieving compressor stability boundary control. Background Technology

[0002] As energy conversion devices, compressors are widely used in aviation and other industrial fields, and their stable operating range must be strictly controlled. In the development of modern aero-engines, as engine design goals continue to evolve towards higher thrust-to-weight ratios and lower fuel consumption, the compressor pressure ratio is also continuously increasing. With increasing stage loads, the compressor's operating environment becomes increasingly harsh, posing greater challenges to its own aerodynamic stability and that of the entire engine. Aerodynamic instability can not only cause compressor performance degradation and blade fatigue damage, but may even lead to engine shutdown, resulting in serious damage to components and the entire engine. Therefore, during design and operation, the distance between the compressor's operating point and its aerodynamic stability boundary must be strictly controlled to ensure its aerodynamic stability. How to accurately predict the compressor's stability boundary under different operating conditions remains an important research topic in the field of aero-engines. Summary of the Invention

[0003] This application provides a compressor system and a method for achieving compressor stability boundary control, which enables low-cost and rapid adjustment of compressor stability, thereby improving R&D efficiency and effectively shortening the test cycle.

[0004] This invention provides a compressor system, including: a compressor, a transition section, a downstream cavity, and a throttling valve; wherein, The compressor's outlet is directly connected to the downstream transfer section; as the system's energy input component, the compressor is used to convert mechanical energy into the pressure energy and kinetic energy of air, providing the required compressed airflow. The transition section is located between the compressor outlet and the downstream cavity inlet. Controllable elements are installed inside the transition section. The transition section is used to adjust the system's B parameter by changing the effective flow area inside the transition section to control the location of the system's blockage point and the effective volume range. The downstream cavity, located after the transition section, has its outlet connected to the throttle valve; the downstream cavity is used to provide an equivalent volume for the system to influence the propagation and feedback intensity of pressure pulsations in the system. A throttle valve, which communicates with the external environment, is the outlet for the system's airflow. It is used to provide the system's equivalent cross-sectional area and equivalent length, and to regulate the system's flow rate and downstream resistance conditions.

[0005] In one exemplary instance, the transition section controls the location of the system's blockage point and the effective volume range by changing the effective flow area within the transition section, thereby adjusting the system's B parameter, including: When the effective flow area inside the transition section is large, the blocking effect is small, the B parameter is higher than the critical value, and surge occurs; when the effective flow area inside the transition section decreases, the blocking effect increases, the volume involved in instability decreases, the B parameter drops below the critical value, and rotational stall occurs.

[0006] In one exemplary instance, the controllable elements disposed within the transition section include: guide vanes with adjustable angles, support plates of different thicknesses, locally variable geometry pipes, or valve devices.

[0007] In one exemplary instance, the compressor is an axial or centrifugal impeller machine.

[0008] In one exemplary instance, the downstream cavity includes a volute, a gas collection chamber, or an expansion pipe.

[0009] This application also provides a method for achieving compressor stability boundary control, based on the compressor system described in any of the above claims, including: During the test bench design phase, a downstream pipeline and cavity with a large volume were selected so that the reference instability mode of the compressor system is surge when the transition section does not form a blocking effect; wherein, the transition section in the compressor system is located between the compressor and the downstream cavity and has a variable effective flow area. During operation or testing, the flow area of ​​the transition section can be adjusted as needed to actively select the instability mode of the system and expand the stability boundary of the compressor.

[0010] In one exemplary instance, the selection of a downstream pipeline and cavity with a large volume, such that the reference instability mode of the compressor system is surge when no blockage effect occurs at the transition section, includes: Based on experience or through calculation of the B parameter, select and design a pipeline system with a larger downstream cavity so that when the transition section is at its maximum flow area, the calculated B parameter of the system is higher than the critical value of compressor surge.

[0011] In one exemplary instance, the transition section does not create a blocking effect, including when the support plate inside the transition section is at its thinnest point or the guide vane has its maximum opening angle.

[0012] In one exemplary instance, adjusting the flow area of ​​the transition section as needed includes: To study the baseline surge condition of the compressor system, the opening of the transition section should be increased to increase the flow area of ​​the transition section. If it is desired to expand the stable operating range of the compressor, the opening of the transition section is reduced to decrease the flow area of ​​the transition section; when it is reduced to below a certain critical value, the B parameter is reduced to below the critical value, and the instability mode of the compressor is converted to rotational stall, thereby expanding the stability boundary of the compressor.

[0013] In one exemplary instance, the adjustment process for the valves and adjustable guide vanes located inside the transition section is accomplished by rotation or angle change; For the fixed support plates or local geometric modifications installed inside the transition section, adjustments can be made by replacement or disassembly.

[0014] The compressor system provided in this application embodiment, without modifying large-scale basic hardware (such as the volute and piping), can actively adjust system parameter B using only an independent, small, and adjustable transition section, achieving switching between surge and rotary stall modes of compressor instability. Based on the principle of the compressor system provided in this application embodiment, by adjusting the turbine guide angle to change the effective flow area, the stability boundary of the upstream compressor or fan is actively expanded, achieving low-cost and rapid adjustment of compressor stability, thereby improving R&D efficiency and effectively shortening the testing cycle. The compressor system provided in this application embodiment has wide applicability, applicable to both independent compression system component testing environments and complex whole-machine environments containing compression systems.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0016] The accompanying drawings are used to provide a further understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0017] Figure 1 This is a schematic diagram of a typical configuration of the Greitzer model; Figure 2 This is a schematic diagram of the composition of the compressor system in an embodiment of this application; Figure 3 This is a comparison chart of the characteristic curves of the compressors in the embodiments of this application; Figure 4 This is a flowchart illustrating the method for implementing compressor stability boundary control in an embodiment of this application. Detailed Implementation

[0018] To make the purpose, technical solutions and advantages of this application more clear, the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of this application can be combined with each other in any way.

[0019] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0021] It is understood that the terms "first" and "second" used in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0023] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0024] The steps illustrated in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases the steps shown or described may be performed in a different order than that presented here.

[0025] Traditional aerodynamic instability research has largely focused on the compressor itself, or bench compression systems with the compressor as the core component. Compressor aerodynamic instability mainly includes two types of phenomena: rotating stall and surge. Rotating stall refers to the phenomenon where a stall cluster formed by localized flow separation rotates circumferentially; its harm is relatively minor, but it can still lead to blade fatigue and sudden performance changes. Surge, on the other hand, is a systemic instability mode involving the coupling of different components of the compression system, posing a greater threat to normal engine operation. Its typical characteristic is low-frequency oscillations in pressure and flow, resulting in significant fluctuations in surface-averaged parameters at different flow directions. Studies have shown that bench factors such as compressor outlet pipe length significantly affect surge boundaries and modes; therefore, surge research must consider the entire compression system, not just the compressor itself.

[0026] For typical compression system configurations, Greitzer proposed a simplified dynamic model in 1976, which uses three elements—compressor, chamber, and throttle valve—to construct the system model, such as... Figure 1 As shown. Within this model framework, a dimensionless B parameter is introduced to quantitatively evaluate the compressor instability characteristics, and its mathematical form is shown in formula (1): (1) In formula (1), U represents the physical rotational speed at the blade tip, a represents the local speed of sound, V represents the equivalent volume of the system, A represents the equivalent cross-sectional area, and L represents the equivalent length. The B parameter is used to comprehensively characterize the dynamic characteristics of the system and to determine the instability mode. When the B parameter is greater than the critical value, the system mainly experiences surge instability; while when the B parameter is less than the critical value, the system tends to experience rotational stall. This theory lays the foundation for determining the instability mode and predicting the stability boundary.

[0027] However, given the potentially severe consequences of instability, expanding the compressor's stability boundary has become a key research focus. Different instability modes correspond to different stability boundary locations, meaning that actively controlling the instability pattern could potentially extend the compressor's operating range. Theoretical analysis shows that the system's equivalent volume V, equivalent length L, and equivalent cross-sectional area A are key parameters influencing instability modes. Therefore, actively controlling instability modes requires adjusting these geometric parameters at the system level. In other words, compressors may experience different types of instability, each occurring at different locations. If the compressor could be artificially made more prone to a particular type of instability, its safe operating range could be expanded.

[0028] In related technologies, the system volume is typically altered by modifying fixed components on the test bench (such as the intake volute and exhaust piping). However, these components are bulky and complex to manufacture, and each modification incurs high costs and lengthy development cycles. Once the test bench system is built, its parameters are essentially fixed, lacking the ability to be flexibly adjusted during testing. Moreover, during the design phase, due to the imperfections in prediction methods, theoretical calculations often only provide a rough range, making it difficult to accurately predict actual flow effects. This increases the uncertainty of testing during the R&D process, leading to higher costs and severely limiting the development efficiency of high-performance compressors.

[0029] To control the instability modes of a compressor and expand its stability boundaries, it is often necessary to modify the system's B-parameters by redesigning and manufacturing large, fixed components of the test rig (such as the intake volute and exhaust piping). However, this approach has several drawbacks. First, these large components are bulky and complex to manufacture, meaning each modification incurs high material and manufacturing costs. Second, once the test rig system is built, its geometric parameters are essentially fixed, lacking the ability to be flexibly adjusted during testing. Finally, due to the limitations of existing prediction methods, theoretical calculations often only provide approximate ranges and cannot accurately reflect the actual flow effects, leading to an over-reliance on trial and error in the development process, resulting in low efficiency.

[0030] To address the aforementioned issues, this application proposes a compressor system and its flexible and efficient compressor stability boundary control method. This allows for convenient and real-time adjustment of key components during testing without requiring large-scale modifications to the main piping or cavity of the test bench. This approach fundamentally bypasses the challenge of accurately predicting the B parameter, thereby avoiding repeated processing.

[0031] Figure 2 This is a schematic diagram of the composition of the compressor system in an embodiment of this application, as shown below. Figure 2 As shown, it may include: a compressor, a transition section, a downstream cavity, and a throttle valve; wherein, An air compressor, as the energy input component of a system, converts mechanical energy into the pressure and kinetic energy of air to provide the required compressed airflow. The compressor outlet is directly connected to a downstream transition section. In some embodiments, the air compressor can be, but is not limited to, axial or centrifugal impeller machinery.

[0032] The transition section, located between the compressor outlet and the downstream cavity inlet, contains controllable elements. The transition section is used to adjust the system's blockage point location and effective volume range by changing the effective flow area within it, thereby regulating the system's B-parameter. In this embodiment, by adjusting the transition section, the compressor instability mode is switched between surge and rotating stall, thus expanding the compressor's stable operating boundary. In one embodiment, the controllable elements within the transition section can be, for example, adjustable-angle guide vanes, support plates of varying thicknesses, locally variable geometry pipes, or valve devices.

[0033] In this embodiment, when the effective flow area inside the transition section is large, the blocking effect is small, and the system B-parameter is higher than the critical value, exhibiting surge. When the effective flow area inside the transition section decreases, the blocking effect intensifies, the volume involved in instability decreases, and the B-parameter drops below the critical value, exhibiting rotational stall. In other words, by manually adjusting the transition section, it is possible to switch between surge and rotational stall, thereby expanding the stability boundary. In this embodiment, due to the introduction of a transition section with an adjustable structure, the system can still flexibly change the B-parameter by adjusting the opening of this section under different operating conditions, thus achieving dynamic adjustment of the stability boundary.

[0034] The downstream cavity, located after the transition section, provides an equivalent volume V to the system, thereby influencing the propagation and feedback intensity of pressure pulsations within the system. The outlet of the downstream cavity is connected to a throttle valve. In one embodiment, the downstream cavity may include a volute, a gas collection chamber, or an expansion pipe, etc.

[0035] A throttle valve, located at the end of the system, is equivalent to a throttling device in a tailpipe or test bench. It is used to provide the system's equivalent cross-sectional area A and equivalent length L, regulating the system flow rate and downstream resistance conditions. The throttle valve ultimately connects to the external environment and is the outlet for the system's airflow.

[0036] Figure 2 The left side view of the transition section is shown in the middle figure. In this embodiment, the transition section 22 is located between the compressor outlet 21 and the downstream cavity 23. It can be seen that the transition section is installed after the compressor outlet 21 and connected to the downstream cavity 23 (downstream volute or gas collecting chamber) to form an adjustable local blockage in the flow channel. Figure 2 The right-hand side of the figure is a cross-sectional view of the connection between the transition section 22 and the compressor outlet 21. In one embodiment, adjustable-angle guide vanes or support plates can be arranged inside the transition section 21 to change the effective flow area of ​​the section. The cross-sectional view clearly shows the relative positional relationship between the transition section 22 and the compressor outlet 21, as well as its embedding method in the entire airflow channel.

[0037] The compressor system in this embodiment forms a complete airflow channel, where the intake air flows sequentially through the compressor, the transition section, the downstream cavity, and the throttle valve before being discharged. Each component in the compressor system performs its specific function. The transition section, as a newly added adjustable unit, enables active control of compressor stability. Its introduction allows the system to flexibly adjust the stability boundary under different operating conditions, effectively improving the operational reliability of the compressor and the overall compression system.

[0038] Combining formula (1) and Figure 2 When the compressor operates at a high speed (generally above 60%), if the support plate in the transition section is thin or has a large opening, its blocking effect on the airflow can be ignored. This is equivalent to having no transition section; the actual blockage point of the system is located at the throttle valve after the downstream cavity. In this case, the equivalent volume V involved in the instability process includes all the space from the compressor outlet to the downstream throttle valve, including the transition section, volute, and piping. The equivalent cross-sectional area A and equivalent length L are taken as the equivalent cross-sectional area and length of the compressor flow path, respectively. At this point, the system's B parameter exceeds the critical value. Once instability occurs, the system exhibits a highly destructive surge with a narrow stability boundary, such as... Figure 3 The curve shown is represented by the solid square in the middle. Figure 3 This is a comparison graph of the compressor characteristic curves in the embodiments of this application. The horizontal axis represents the normalized mass flow rate, and the vertical axis represents the normalized total pressure ratio. Figure 3 The curves are shown at different speeds of 65%, 75%, and 85%. Figure 3 The curves in the figure show the compressor performance of the system when a thinner support plate or a larger opening is used in the transition section. It can be seen that at different speeds of 65%, 75%, and 85%, the curves show inflection points and drops in the low flow region, indicating that the instability boundary is narrow and the instability mode is surge.

[0039] When the blocking effect of the transition section is increased by replacing it with a thicker support plate or reducing the support plate angle, the transition section itself replaces the original downstream throttle valve and becomes the main blockage point of the system. In this case, when instability occurs, the effective volume V affected by the reverse pressure pulsation is significantly reduced, limited to the narrow space between the compressor outlet and the transition section, while the equivalent cross-sectional area A and equivalent length L still take the cross-sectional area and length of the compressor flow channel. Thus, the system's B parameter decreases below the critical value, and the instability mode changes from a highly destructive surge to a less destructive rotating stall with a wider stability boundary, such as... Figure 3 The curve indicated by the solid circle represents the compressor performance of the system when thicker support plates or a reduced blade opening are used in the transition section. Compared to the thin-blade condition, the curve maintains higher stability in the low-flow region, indicating that the instability mode transforms into rotating stall, and the stability boundary is widened.

[0040] As seen in the example above, if the blocking effect of the transition section is insufficient, the system will still exhibit the traditional surge phenomenon with a narrow instability boundary; however, when the support plate is thickened or the opening is reduced, that is, when the blocking effect of the transition section increases, the system turns into rotational stall and the boundary is expanded.

[0041] In summary, the compressor system provided in this application, based on the traditional Greitzer model theory, achieves active control of the instability boundary by adding an adjustable transition section between the compressor and the downstream cavity. In this application, the transition section can actively change its effective flow area by setting adjustable-angle support plates or replacing them with support plates of different thicknesses, thereby altering the dynamic characteristics of the compressor system, reducing the B-parameter, and expanding the stable operating boundary of the compressor. When the effective flow area of ​​the transition section decreases below a certain critical value, the backflow caused by pressure fluctuations is insufficient to trigger surge, and the instability mode is limited to rotational stall; at this point, the stable boundary of the compressor system is widened. However, when the effective flow area of ​​the transition section is large or produces almost no blocking effect, and the volume of the downstream cavity of the compressor is sufficient to cause the system B-parameter to exceed the critical value, the compressor will still experience surge.

[0042] In this embodiment, the specific physical implementation and geometric form of the transition section are not limited. In practical applications, different solutions can be selected according to requirements, including but not limited to: using valves, adjustable guide vanes, fixed support plates, or modifying the geometry of local pipelines. In one embodiment, if adjustable guide vanes are used, only one installation is required, and the effective flow area can be continuously adjusted during the test, facilitating flexible experimentation. In another embodiment, if support plates of different thicknesses are replaced or the flow channel geometry is modified, multiple disassembly and assembly may be required under different operating conditions.

[0043] The compressor system provided in this application embodiment, without modifying large-scale basic hardware (such as the volute and piping), can actively adjust system parameter B using only an independent, small, and adjustable transition section, achieving switching between surge and rotating stall modes of compressor instability. The compressor system provided in this application embodiment is widely applicable, suitable for both independent compression system component testing environments and complex whole-machine environments including compression systems, such as aero-engines. Taking an aero-engine as an example, the equivalent cross-sectional area A and equivalent length L can be calculated based on the geometric parameters of the fan or compressor channel, with the downstream combustion chamber considered as the equivalent volume V. In this case, the turbine inlet guide vane can be considered as an adjustable element equivalent to the transition section, the afterburner as an additional cavity, and the exhaust nozzle as an equivalent throttle valve. Within this framework, based on the principle of the compressor system provided in this application embodiment, the effective flow area is changed by adjusting the turbine guide vane angle, thereby actively expanding the stability boundary of the upstream compressor or fan.

[0044] Figure 4 This is a flowchart illustrating the method for implementing compressor stability boundary control in an embodiment of this application, as shown below. Figure 4 As shown, the compressor system provided based on the embodiments of this application may include: Step 400: During the test bench design phase, a downstream pipeline and cavity with a large volume are selected so that the reference instability mode of the compressor system is surge when the transition section does not form a blocking effect; wherein, the transition section is set between the compressor and the downstream cavity and has a variable effective flow area.

[0045] During the test bench design phase, a pipeline system with a large downstream cavity is selected and designed based on experience or preliminary calculations of the B-parameter. The design objective is that, when the transition section is at its maximum effective flow area, the B-parameter of the system calculated according to formula (1) should be significantly higher than the critical value of compressor surge (usually about 0.8), thereby ensuring that the baseline instability mode is surge. The purpose of this design is that when no blocking effect is formed in the transition section (such as when the support plate is at its thinnest or the guide vane is in an unrestricted state with the largest opening and closing angle), the system instability manifests as a highly destructive surge, providing a basis for subsequent active adjustment.

[0046] In this embodiment, the transition section is equipped with several controllable elements (such as guide vanes with adjustable angles, support plates of different thicknesses, or variable geometry of local pipelines) to change the effective flow area in the local area.

[0047] In this embodiment, the minimum effective flow area of ​​the transition section design should ensure that the B parameter of the compressor system can be reduced to below the critical value, so that the instability mode changes from surge to rotating stall. Different compressors have different requirements for this minimum value, which can be customized by combining the compression capacity and performance parameters of the target compressor.

[0048] Step 401: During operation or testing, adjust the effective flow area of ​​the transition section as needed to actively select the instability mode of the system and expand the stability boundary of the compressor.

[0049] In one exemplary instance, to study the baseline surge condition of a compressor system, the opening of the transition section can be increased, i.e., the effective flow area of ​​the transition section can be increased. When the effective flow area of ​​the transition section increases or the blocking effect disappears, the downstream large cavity re-engages in the system dynamics, the B parameter returns to above the critical value, and the system exhibits surge instability.

[0050] In one exemplary instance, to extend the stability boundary and make the compressor system more stable (i.e., to expand the compressor's stable operating range), the transition section opening can be reduced, i.e., the effective flow area of ​​the transition section is decreased. This limits the effective volume V of the system to a smaller range. When reduced to below a certain critical value, the compressor system's B parameter decreases below the critical value, and the compressor's instability mode changes to rotating stall, thereby extending the compressor's stable operating boundary. In this way, it is possible to select whether the compressor is in a narrow-boundary surge or a wide-boundary rotating stall state, depending on the experimental purpose or actual operating conditions.

[0051] In this embodiment, by adjusting the effective flow area of ​​the transition section as needed, that is, by controlling the opening (or blocking degree) of the transition section, the unstable mode of the compressor system is actively selected, thereby expanding the stability boundary of the compressor.

[0052] In one embodiment, for valves and adjustable guide vanes, the adjustment process can be completed directly by rotation or angle change, which is convenient. In another embodiment, for solutions with fixed support plates or partial geometric modifications, adjustment needs to be achieved through replacement or disassembly.

[0053] The method for achieving compressor stability boundary control provided in this application does not limit the specific method for limiting the effective flow area. Any technical solution capable of achieving this function is within the scope of protection of this application. Whether it is by installing adjustable-angle guide vanes, replacing support plates of different thicknesses, adding controllable valves, or directly modifying the local flow channel geometry, the effective flow area can be limited. Therefore, this application emphasizes active regulation of stability through localized and controllable flow blockage, rather than being limited to a specific hardware implementation.

[0054] The method for achieving compressor stability boundary control provided in this application, through an independent, small, and adjustable transition section, enables active adjustment of system B parameters, achieving switching between compressor instability modes of surge and rotating stall. This method significantly reduces development costs, improves flexibility and efficiency, and achieves low-cost, rapid adjustment of compressor stability, providing an efficient and feasible technical path for stability research of compressors and their overall systems. Compared with traditional methods, this application not only significantly improves development efficiency but also effectively shortens the testing cycle, thus providing a more reliable and economical approach for the development of new high-performance compressors.

[0055] The method for controlling the compressor stability boundary provided in this application is a convenient way to widen the compressor stability boundary. Its core principle is to add an adjustable device, or transition section, near the downstream end of the compressor to limit the local flow cross-sectional area. When the compressor flow tends to become unstable, this device can effectively suppress the intensity of the reverse pressure pulsation generated at the moment of flow collapse, thereby changing the instability mode from a highly destructive surge to a relatively mild rotating stall, ultimately achieving the goal of widening the compressor stability boundary.

[0056] The method for achieving compressor stability boundary control provided in this application has a wide range of applications. It can be used in fan test bench configurations as well as in different types of compressor systems, such as multi-stage axial compressors and axial / centrifugal combined compressors. Its application scenarios are not limited to independent compression system component testing environments, but also applicable to complex complete engine systems, such as aero-engines. In complete engine applications, the geometric components involved in this invention are not limited to test bench elements such as the volute or piping. Existing engine components such as combustion chambers, variable turbine guide vanes, afterburners, and exhaust nozzles can all be considered as equivalent functional modules for implementing the principles of this invention and applied accordingly.

[0057] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A compressor system, characterized in that, include: Compressor, transition section, downstream chamber, and throttle valve; among which, The compressor's outlet is directly connected to the downstream transfer section; as the system's energy input component, the compressor is used to convert mechanical energy into the pressure energy and kinetic energy of air, providing the required compressed airflow. The transition section is located between the compressor outlet and the downstream cavity inlet. Controllable elements are installed inside the transition section. The transition section is used to adjust the system's B parameter by changing the effective flow area inside the transition section to control the location of the system's blockage point and the effective volume range. The downstream cavity, located after the transition section, has its outlet connected to the throttle valve; the downstream cavity is used to provide an equivalent volume for the system to influence the propagation and feedback intensity of pressure pulsations in the system. A throttle valve, which communicates with the external environment, is the outlet for the system's airflow. It is used to provide the system's equivalent cross-sectional area and equivalent length, and to regulate the system's flow rate and downstream resistance conditions.

2. The compressor system according to claim 1, wherein, The transition section controls the location of system blockages and the effective volume range by changing the effective flow area within the transition section, thereby adjusting the system's B parameters, including: When the effective flow area inside the transition section is large, the blocking effect is small, the B parameter is higher than the critical value, and surge occurs; when the effective flow area inside the transition section decreases, the blocking effect increases, the volume involved in instability decreases, the B parameter drops below the critical value, and rotational stall occurs.

3. The compressor system according to claim 1 or 2, wherein, The controllable components inside the transition section include: guide vanes with adjustable angles, support plates of different thicknesses, and locally variable geometry pipes or valve devices.

4. The compressor system according to claim 1, wherein, The compressor is an axial flow or centrifugal impeller machine.

5. The compressor system according to claim 1, wherein, The downstream cavity includes a volute, a gas collection chamber, or an expansion pipeline.

6. A method for achieving compressor stability boundary control, characterized in that, The compressor system according to any one of claims 1-5 includes: During the test bench design phase, a downstream pipeline and cavity with a large volume were selected so that the reference instability mode of the compressor system is surge when the transition section does not form a blocking effect; wherein, the transition section in the compressor system is located between the compressor and the downstream cavity and has a variable effective flow area. During operation or testing, the flow area of ​​the transition section can be adjusted as needed to actively select the instability mode of the system and expand the stability boundary of the compressor.

7. The method according to claim 6, wherein, The selection of downstream pipelines and cavities with large volumes, such that the reference instability mode of the compressor system is surge when no blockage effect occurs at the transition section, includes: Based on experience or through calculation of the B parameter, select and design a pipeline system with a larger downstream cavity so that when the transition section is at its maximum flow area, the calculated B parameter of the system is higher than the critical value of compressor surge.

8. The method according to claim 7, wherein, The transition section does not create a blocking effect, including: the support plate inside the transition section is at its thinnest point or the guide vane has its maximum opening angle.

9. The method according to claim 6, wherein, The adjustment of the flow area of ​​the transfer section as needed includes: To study the baseline surge condition of the compressor system, the opening of the transition section should be increased to increase the flow area of ​​the transition section. If it is desired to expand the stable operating range of the compressor, the opening of the transition section is reduced to decrease the flow area of ​​the transition section; when it is reduced to below a certain critical value, the B parameter is reduced to below the critical value, and the instability mode of the compressor is converted to rotational stall, thereby expanding the stability boundary of the compressor.

10. The method according to claim 9, wherein, For the valves and adjustable guide vanes installed inside the transition section, the adjustment process is completed by rotation or angle change; For the fixed support plates or local geometric modifications installed inside the transition section, adjustments can be made by replacement or disassembly.

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