A Simulation Method for S2 Flow Field Considering the Influence of Bleed Air in the Intermediate Stage

Abstract

This application belongs to the field of aerodynamic design of aeroengine fans and compressors, and specifically relates to an S2 flow field simulation method considering the influence of intermediate stage air extraction, including: adding a diversion streamline in the S2 flow field; the front end of the diversion streamline extends to the inlet of the S2 flow field, and the rear end extends to the intermediate stage air extraction outlet of the S2 flow field; taking the space between the diversion streamline and the outer flow path of the S2 flow field as the outer duct; taking the space between the diversion streamline and the inner flow path of the S2 flow field as the inner duct; and simulating the inner duct flow field and the outer duct flow field respectively. In the above S2 flow field simulation method considering the influence of intermediate stage air extraction, by adding a diversion streamline in the S2 flow field and dividing the S2 flow field into the inner duct and the outer duct for separate simulation, it is possible to simultaneously simulate the influence of intermediate stage air extraction on the pressure ratio matching of the stages before and after the air extraction position, as well as the influence on the radial pressure ratio matching after the air extraction position.

Description

Technical Field

[0001] This application belongs to the field of aerodynamic design of aero-engine fan compressors, and particularly relates to an S2 flow field simulation method considering the influence of intermediate stage bleeding. Background Technique

[0002] The intermediate stage bleeding in the fan compressor of an aero-engine has the following two aspects of influence on the S2 flow field:

[0003] 1) It will reduce the flow rate after the bleeding position in the S2 flow field. Taking the bleeding position as the boundary, it will change the pressure ratio matching between the front stage and the rear stage in the S2 flow field;

[0004] 2) It will cause the fluid at the tip region after the bleeding position in the S2 flow field to decelerate, and change the radial matching of the pressure ratio after the bleeding position in the S2 flow field.

[0005] Currently, when simulating the S2 flow field considering the influence of intermediate stage bleeding in the fan compressor of an aero-engine, the meridional velocity level after the bleeding position is mostly simulated through the boundary layer blockage factor or the flow coefficient. Only the influence of intermediate stage bleeding on the pressure ratio matching before and after the bleeding position in the S2 flow field is considered, while the influence on the radial matching of the pressure ratio after the bleeding position in the S2 flow field is ignored. As a result, the tip region after the bleeding position in the S2 flow field is matched at too high a pressure ratio, and it enters the surge boundary in advance under the condition that the boosting capacity has not been fully exerted in other sections, which has an adverse impact on the surge margin of the compressor. This problem is particularly prominent when the bleeding volume is large.

[0006] In view of the existence of the above technical defects, this application is proposed.

[0007] It should be noted that the disclosure of the above background technical content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available on the filing date of this application, the above background technology should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0008] The purpose of this application is to provide a compressor S2 flow field simulation method considering the influence of intermediate stage bleeding to overcome or mitigate at least one aspect of the known technical defects.

[0009] The technical solution of this application is as follows:

[0010] A compressor S2 flow field simulation method considering the influence of intermediate stage bleeding includes:

[0011] Adding shunt streamlines in the S2 flow field;

[0012] The front section of the shunt streamline extends to the inlet of the S2 flow field, and the rear section extends to the intermediate stage bleeding outlet of the S2 flow field;

[0013] The outer flow path between the split flow line and the outer flow path of the S2 flow field is defined as the outer flow path;

[0014] The inner flow path between the split flow line and the inner flow path of the S2 flow field is defined as the inner flow path;

[0015] The inner flow field and the outer flow field are simulated separately.

[0016] According to at least one embodiment of the present application, in the above S2 flow field simulation method considering the influence of intermediate stage air extraction,

[0017] wherein,

[0018] Rf is the radius of the split flow line;

[0019] k is the split flow line adjustment coefficient;

[0020] Ro is the radius of the outer flow path of the S2 flow field;

[0021] x is the ratio of the intermediate stage air extraction volume of the S2 flow field to the total flow volume of the S2 flow field;

[0022] Ri is the radius of the inner flow path of the S2 flow field.

[0023] According to at least one embodiment of the present application, in the above S2 flow field simulation method considering the influence of intermediate stage air extraction, k = 0.95 - 1.0.

[0024] The present application has at least the following beneficial technical effects:

[0025] A S2 flow field simulation method considering the influence of intermediate stage air extraction is provided. A split flow line is added in the S2 flow field, and the S2 flow field is divided into an inner flow path and an outer flow path for separate simulation, which can simultaneously simulate the influence of intermediate stage air extraction on the pressure ratio matching of the stages before and after the air extraction position and the influence on the radial pressure ratio matching after the air extraction position. Description of the Drawings

[0026] Figure 1 is a schematic diagram of the existing S2 flow field simulation considering the influence of intermediate stage air extraction;

[0027] Figure 2 is a schematic diagram of the S2 flow field simulation considering the influence of intermediate stage air extraction provided by the embodiment of the present application;

[0028] Figure 3 is a schematic diagram of the comparison of the radial meridional velocity distribution of the blades in the subsequent stages obtained by the existing S2 flow field simulation method considering the influence of intermediate stage air extraction disclosed in the present application;

[0029] Figure 4It is a schematic diagram showing the comparison of the radial distribution of the blade pressure ratio in the subsequent stages obtained by the S2 flow field simulation method disclosed in this application and considering the influence of intermediate stage bleed air.

[0030] To better illustrate this embodiment, some components in the drawings are omitted, enlarged or reduced, which do not represent the dimensions of the actual product; in addition, the drawings are for illustrative purposes only, and their positional relationships are limited to illustrative purposes only and cannot be construed as a limitation of this patent. Detailed implementation manners

[0031] To make the technical solutions and their advantages of this application clearer, the technical solutions of this application will be further described clearly and completely below in conjunction with the drawings. It can be understood that the specific embodiments described herein are only part of the embodiments of this application, which are only used to explain this application and not to limit this application. It should be noted that for the convenience of description, only the parts related to this application are shown in the drawings, and other related parts can refer to the general design. Without conflict, the embodiments and the technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0032] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application should be the ordinary meanings understood by those of ordinary skill in the field to which this application belongs. The words indicating directions such as "upper", "lower", "left", "right", "center", "vertical", "horizontal", "inner", "outer", etc. used in the description of this application are only used to indicate the relative directions or positional relationships, rather than implying that the device or element must have a specific orientation, be constructed and operated in a specific orientation. When the absolute position of the object being described changes, its relative positional relationship may also change accordingly, so it cannot be construed as a limitation of this application. The terms "first", "second", "third" and similar terms used in the description of this application are only for descriptive purposes to distinguish different components and cannot be construed as indicating or implying relative importance. The similar words such as "a", "one" or "the" used in the description of this application should not be construed as an absolute limitation of the quantity, but should be understood as having at least one. The words such as "including" or "comprising" used in the description of this application are intended to mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects.

[0033] In addition, it should be noted that, unless otherwise clearly specified and limited, the similar terms such as "installed", "connected", and "linked" used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can also be the communication inside two components. Those skilled in the art can understand its specific meaning in this application according to the specific situation.

[0034] The following will further elaborate on this application in conjunction with the attached Figures 1 to 4 drawings.

[0035] An S2 flow field simulation method considering the influence of intermediate stage air extraction includes:

[0036] Adding a diversion streamline in the S2 flow field;

[0037] The front end of the diversion streamline extends to the inlet of the S2 flow field, and the rear end extends to the intermediate stage air extraction outlet of the S2 flow field;

[0038] Taking the space between the diversion streamline and the external flow path of the S2 flow field as the outer flow;

[0039] Taking the space between the diversion streamline and the internal flow path of the S2 flow field as the internal flow;

[0040] Simulating the internal flow field and the external flow field respectively.

[0041] For the S2 flow field simulation method considering the influence of intermediate stage air extraction disclosed in the above embodiments, those skilled in the art can understand that by adding a diversion streamline in the S2 flow field and dividing the S2 flow field into internal and external flows for separate simulations, it is possible to simultaneously simulate the influence of intermediate stage air extraction on the pressure ratio matching of the stages before and after the air extraction position, as well as the influence on the radial pressure ratio matching after the air extraction position.

[0042] In some alternative embodiments, in the above S2 flow field simulation method considering the influence of intermediate stage air extraction,

[0043] wherein,

[0044] Rf is the radius of the diversion streamline;

[0045] k is the adjustment coefficient of the diversion streamline;

[0046] Ro is the radius of the external flow path of the S2 flow field;

[0047] x is the ratio of the intermediate stage air extraction volume of the S2 flow field to the total flow volume of the S2 flow field;

[0048] Ri is the radius of the internal flow path of the S2 flow field.

[0049] For the S2 flow field simulation method considering the influence of intermediate stage air extraction disclosed in the above embodiments, those skilled in the art can understand that it determines the radius of the split streamline based on the radius of the outer flow path of the S2 flow field, the radius of the inner flow path of the S2 flow field, and the ratio of the intermediate stage air extraction volume to the total flow volume of the S2 flow field, making the S2 flow field simulation easy to converge.

[0050] In some alternative embodiments, in the above S2 flow field simulation method considering the influence of intermediate stage air extraction, k = 0.95 - 1.0. Through actual verification, adjusting the radius of the split streamline with the range split streamline adjustment coefficient can make the S2 flow field simulation easy to converge.

[0051] In a specific example, the existing method and the method disclosed in this application are used to simulate the S2 flow field considering the influence of intermediate stage air extraction. The radial meridional velocity distribution of the blades in the stage behind the air extraction position and the radial matching of the pressure ratio are as Figures 3 - 4 shown.

[0052] When using the existing method to simulate the S2 flow field considering the influence of intermediate stage air extraction, the tip part of the blade in the stage behind the air extraction position of the S2 flow field is matched with an overly high pressure ratio, which is closer to the pressure ratio limit relative to the root part. It will enter the surge boundary in advance when the boosting capacity of other sections has not been fully exerted.

[0053] When using the method disclosed in this application to simulate the S2 flow field considering the influence of intermediate stage air extraction, the pressure ratio of the blades in the stage behind the air extraction position of the S2 flow field is evenly distributed in the radial direction, and the situation of entering the surge boundary in advance when the boosting capacity of other sections has not been fully exerted will not occur.

[0054] The various embodiments in the specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0055] So far, the technical solution of this application has been described in combination with the preferred embodiments shown in the drawings. Those skilled in the art should understand that the protection scope of this application is obviously not limited to these specific embodiments. Without departing from the principle of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this application.

Claims

1. A simulation method for the S2 flow field considering the influence of intermediate-stage air extraction, characterized in that, it includes: adding a shunt streamline in the S2 flow field, and the radius Rf of the shunt streamline is: wherein, k is the shunt streamline adjustment coefficient; Ro is the radius of the outer flow path of the S2 flow field; x is the ratio of the intermediate-stage air extraction volume of the S2 flow field to the total flow volume of the S2 flow field; Ri is the radius of the inner flow path of the S2 flow field; the front end of the shunt streamline extends to the inlet of the S2 flow field, and the rear end extends to the intermediate-stage air extraction outlet of the S2 flow field; taking the space between the shunt streamline and the outer flow path of the S2 flow field as the outer duct; taking the space between the shunt streamline and the inner flow path of the S2 flow field as the inner duct; simulating the inner duct flow field and the outer duct flow field respectively.

2. The simulation method for the S2 flow field considering the influence of intermediate-stage air extraction according to claim 1, characterized in that, k＝0.95～1.0。

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