A method for determining the pressure distortion sensitivity coefficient of a compression system

Abstract

The present invention provides a method for determining the pressure distortion sensitivity coefficient of a compression system. The compression system includes a core engine-driven fan and a compressor. The method comprises the following steps: S1: Design a distortion generating device; S2: Place the core engine-driven fan and the compressor in the compression system and respectively obtain the aerodynamic performance parameters; S3: Calculate the sensitivity coefficient based on the aerodynamic performance parameters obtained in S2. This method takes into account the sequence of instability between the CDFS and the compressor, can accurately simulate the distortion situation of the real flow field at the compressor inlet, obtain the pressure distortion sensitivity coefficients of the compression system and its components under the matching working environment of the CDFS and the compressor, solves the problem of being unable to accurately obtain the pressure distortion sensitivity coefficients of the compression system and its components under the matching working environment, and can be widely applied to the intake pressure distortion test of engines / compression components.

Description

Technical Field

[0001] The present invention belongs to the technical field of aeroengines, and particularly relates to a method for determining the pressure distortion sensitivity coefficient of a compression system. Background Art

[0002] As one of the key components of a gas turbine engine, the aerodynamic stability of a compressor is the main factor determining the stability of the gas turbine engine, and the strong pressurization process of the internal air flow in the compressor determines its characteristic of aerodynamic instability. Currently, a compressor structure with a core engine driven fan (abbreviation: CDFS) is often adopted in a variable cycle engine, and its structural schematic diagram is shown in Figure 4 , and there is a bypass duct at the CDFS outlet for flow diversion. Considering the pursuit of high stealth performance by the variable cycle engine and the strong coupled aerodynamic influence between the CDFS and the compressor, this puts higher requirements on the aerodynamic stability of the CDFS and the compressor. Therefore, how to accurately obtain the pressure distortion sensitivity coefficient of this compression system becomes crucial.

[0003] The intake pressure distortion test is one of the important channels to obtain the pressure distortion sensitivity coefficient at present. In the past, the method of conducting distortion tests on individual compression components was adopted to obtain independent pressure distortion sensitivity coefficients. However, due to the strong coupled design of the CDFS and the compressor, there are still the following problems with this individual test method:

[0004] 1) It is impossible to identify the sequence of instability of the CDFS and the compressor;

[0005] 2) It is impossible to accurately simulate the distortion situation of the real flow field at the compressor inlet;

[0006] 3) It is impossible to obtain the pressure distortion sensitivity coefficients of the compression system and its components under the matching working environment of the CDFS and the compressor. Summary of the Invention

[0007] In order to solve the above problems, the purpose of the present invention is to provide a method for determining the pressure distortion sensitivity coefficient of a compression system, and the compression system is a compressor structure with a CDFS. This method considers the sequence of instability of the CDFS and the compressor, can accurately simulate the distortion situation of the real flow field at the compressor inlet, and obtain the pressure distortion sensitivity coefficients of the compression system and its components under the matching working environment of the CDFS and the compressor.

[0008] In order to achieve the above purpose, the present invention provides the following technical solution. A method for determining the pressure distortion sensitivity coefficient of a compression system is provided, and the compression system includes a core engine driven fan and a compressor. The method includes the following steps:

[0009] S1: Design the distortion generating device;

[0010] S2: Place the core engine-driven fan and compressor in the compression system, and respectively obtain the aerodynamic performance parameters of the compression system, the core engine-driven fan in the compression system, and the compressor in the compression system.

[0011] S3: Calculate the sensitivity coefficients of the compression system, the core engine-driven fan, and the compressor respectively based on the aerodynamic performance parameters obtained in S2.

[0012] The method for determining the sensitivity coefficient of the compression system pressure distortion provided by the present invention also has the following feature: the distortion generating device in S1 is a sector-shaped plug structure.

[0013] The method for determining the sensitivity coefficient of the compression system pressure distortion provided by the present invention also has the following features: the sector angle θ of the sector-shaped plug structure is 150° - 180°; the thickness of the sector-shaped plug is 10 - 20 mm; the insertion depth L of the sector-shaped plug is 0.1D - 0.5D, where D is the diameter of the intake passage of the compression system.

[0014] The method for determining the sensitivity coefficient of the compression system pressure distortion provided by the present invention also has the following feature: the plug is installed 2D - 3D upstream of the inlet of the core engine-driven fan during the test.

[0015] The method for determining the sensitivity coefficient of the compression system pressure distortion provided by the present invention also has the following feature: the steps for obtaining the aerodynamic performance of the compression system are as follows:

[0016] a) Keep the original adjustment law unchanged, and the adjustment law includes the inlet guide vane angle β CF0 of the CDFS, the inlet guide vane angle β C0 of the compressor, and the bypass ratio B0;

[0017] b) Conduct a uniform flow test to measure the aerodynamic performance parameters of the compression system;

[0018] c) After inserting the distortion generating device into the intake passage, conduct a distorted flow test to measure the flow-pressure ratio characteristics of the compression system and the comprehensive distortion index W CF at the inlet of the compression system.

[0019] The method for determining the sensitivity coefficient of the compression system pressure distortion provided by the present invention also has the following feature: in the uniform flow test, when measuring the aerodynamic performance parameters of the compression system, each characteristic line has no less than 6 points and ensures that a complete characteristic line can be formed.

[0020] The method for determining the aerodynamic performance of the core engine-driven fan in the compression system provided by the present invention also has the following features:

[0021] A: Keep the original adjustment law unchanged, conduct a uniform flow test, and measure the flow rate-pressure ratio characteristics of the core engine-driven fan;

[0022] B: During the measurement of the surge point parameters, if the compressor becomes unstable first, close the inlet guide vane angle of the compressor by 0.5°, and at the same time reduce the bypass ratio by 0.1B0;

[0023] C: Repeat step B) until the core engine-driven fan becomes unstable first, record the inlet guide vane angle β of the compressor at this time C1 and the bypass ratio B1, and measure the surge point parameters;

[0024] D: If the compressor still becomes unstable first when the guide vane angle and the bypass ratio reach the limit boundary, it indicates that the pressure distortion sensitivity coefficient of the core engine-driven fan in this system is zero, and the distorted flow test is no longer carried out;

[0025] E: Keep the adjustment laws of β CF0 、β C1 、B1 unchanged, conduct a distorted flow test, and measure the flow rate-pressure ratio characteristics of the core engine-driven fan and the comprehensive distortion index at the inlet of the core engine-driven fan

[0026] The method for determining the pressure distortion sensitivity coefficient of the compression system provided by the present invention also has the following characteristics. The steps for obtaining the aerodynamic performance of the compressor in the compression system are as follows:

[0027] a) Keep the original adjustment law unchanged, conduct a uniform flow test, and measure the flow rate-pressure ratio characteristics of the compressor;

[0028] b) During the measurement of the surge point parameters, if the core engine-driven fan becomes unstable first, close the inlet guide vane angle of the core engine-driven fan by 0.5°, and at the same time increase the bypass ratio by 0.1B0;

[0029] c) Repeat step b) until the compressor becomes unstable first, record the inlet guide vane angle β of the core engine-driven fan at this time CF1 and the bypass ratio B2, and measure the surge point parameters;

[0030] d) If the core engine-driven fan still becomes unstable first when the guide vane angle and the bypass ratio reach the limit boundary, it indicates that the pressure distortion sensitivity coefficient of the compressor in this system is zero, and the distorted flow test is no longer carried out;

[0031] e) Keep the adjustment laws of β CF0 、β CF1 、B2 unchanged, conduct a distorted flow test, and measure the flow rate-pressure ratio characteristics of the compressor and the comprehensive distortion index at the inlet of the compressor

[0032] The method for determining the pressure distortion sensitivity coefficient of the compression system provided by the present invention further has the following characteristics. The calculation steps of the pressure distortion sensitivity coefficient in S3 are as follows:

[0033] S3.1: Calculate the stability margin SM under uniform intake conditions uni

[0034] SM uni =(π1 / W c1 ) / (π2 / W c2 ) -1

[0035] where π1 is the choke pressure ratio of the uniform flow characteristic, W c1 is the converted flow rate at the choke point of the uniform flow characteristic; π2 is the operating point pressure ratio of the uniform flow, W c2 is the converted flow rate at the operating point of the uniform flow;

[0036] S3.2: Calculate the stability margin SM under distorted intake conditions uni

[0037] SM dis =(π3 / W c3 ) / (π4 / W c4 ) -1

[0038] where π3 is the choke pressure ratio of the distorted flow characteristic, W c3 is the converted flow rate at the choke point of the distorted flow characteristic, π4 is the operating point pressure ratio of the distorted flow, W c4 is the converted flow rate at the operating point of the distorted flow;

[0039] S3.3: Calculate the pressure distortion sensitivity coefficient α

[0040]

[0041] where, is the inlet comprehensive distortion index.

[0042] Beneficial effects

[0043] The method for determining the pressure distortion sensitivity coefficient of the compression system provided by the present invention takes into account the sequence of CDFS and compressor instability, can accurately simulate the distortion of the real flow field at the compressor inlet, obtain the pressure distortion sensitivity coefficients of the compression system and its components under the working environment of CDFS and compressor matching, solves the problem of being unable to accurately obtain the pressure distortion sensitivity coefficients of the compression system and its components under the matching working environment, and can be widely applied to the intake pressure distortion test of engines / compression components. Description of the drawings

[0044] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the accompanying drawings required for the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0045] Figure 1 It is a flowchart of the method for determining the pressure distortion sensitivity coefficient of the compression system provided by the embodiments of the present invention;

[0046] Figure 2 It is a schematic diagram of the sector fixed plugboard in the embodiments of the present invention;

[0047] Figure 3 It is the characteristics and working line in the method for determining the pressure distortion sensitivity coefficient of the compression system provided by the embodiments of the present invention;

[0048] Figure 4 It is a schematic diagram of the compressor structure with CDFS. Detailed implementation manners

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. However, it should be noted that these implementation manners do not limit the present invention. Any equivalent transformation or substitution in terms of function, method, or structure made by those of ordinary skill in the art based on these implementation manners falls within the protection scope of the present invention.

[0050] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0051] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0052] The terms "installed", "connected", and "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] As Figures 1-3 shown, an embodiment of the present invention provides a method for determining the sensitivity coefficient of the compression system pressure distortion. The compression system includes a core engine-driven fan and a compressor. The method includes the following steps:

[0054] S1: Design a distortion generating device;

[0055] S2: Place the core engine-driven fan and the compressor in the compression system, and respectively obtain the aerodynamic performance parameters of the compression system, the core engine-driven fan in the compression system, and the compressor in the compression system;

[0056] S3: Calculate the sensitivity coefficients of the compression system, the core engine-driven fan, and the compressor respectively through the aerodynamic performance parameters obtained in S2.

[0057] In some embodiments, the distortion generating device in S1 is a sector-shaped plug structure.

[0058] In some embodiments, the sector angle θ of the sector-shaped plug structure is 150° - 180°; the thickness of the sector-shaped plug is 10 - 20 mm; the insertion depth L of the sector-shaped plug is 0.1D - 0.5D, where D is the diameter of the intake passage of the compression system. In order to meet the requirements of different intake distortion intensities in the test, the insertion depth takes multiple values at an interval threshold of 0.1D.

[0059] In some embodiments, the plug is installed at 2D - 3D upstream of the inlet of the core engine-driven fan during the test.

[0060] In some embodiments, the steps for obtaining the aerodynamic performance of the compression system are as follows:

[0061] a) Keep the original adjustment rule unchanged. The adjustment rule includes the inlet guide vane angle β CF0 of the CDFS, the inlet guide vane angle β C0 of the compressor, and the bypass ratio B0;

[0062] b) Conduct a uniform flow test to measure the aerodynamic performance parameters of the compression system;

[0063] c) After inserting the distortion generating device into the intake passage, conduct a distorted flow test to measure the flow pressure ratio characteristics of the compression system and the comprehensive distortion index at the inlet of the compression system.

[0064] In some embodiments, during the uniform flow test, when measuring the aerodynamic performance parameters of the compression system, each characteristic line has no less than 6 points, and it is ensured that a complete characteristic line can be formed.

[0065] In some embodiments, the steps for obtaining the aerodynamic performance of the core engine driving the fan in the compression system are as follows:

[0066] A: Keep the original adjustment law unchanged, conduct a uniform flow test, and measure the flow pressure ratio characteristics of the core engine driving the fan.

[0067] B: During the measurement of the surge point parameters, if the compressor becomes unstable first, close the inlet guide vane angle of the compressor by 0.5°, and at the same time reduce the bypass ratio by 0.1B0.

[0068] C: Repeat step B) until the core engine driving the fan becomes unstable first, and record the inlet guide vane angle β of the compressor at this time C1 and the bypass ratio B1, and measure the surge point parameters.

[0069] D: If the compressor still becomes unstable first when the guide vane angle and the bypass ratio reach the limit boundary, it indicates that the pressure distortion sensitivity coefficient of the core engine driving the fan in this system is zero, and the distorted flow test is no longer carried out.

[0070] E: Keep the adjustment laws of β CF0 and β C1 and B1 unchanged, conduct a distorted flow test, and measure the flow pressure ratio characteristics of the core engine driving the fan and the comprehensive distortion index at the inlet of the core engine driving the fan.

[0071] In some embodiments, the steps for obtaining the aerodynamic performance of the compressor in the compression system are as follows:

[0072] a) Keep the original adjustment law unchanged, conduct a uniform flow test, and measure the flow pressure ratio characteristics of the compressor.

[0073] b) During the measurement of the surge point parameters, if the core engine driving the fan becomes unstable first, close the inlet guide vane angle of the core engine driving the fan by 0.5°, and at the same time increase the bypass ratio by 0.1B0.

[0074] c) Repeat step b) until the compressor becomes unstable first, and record the inlet guide vane angle β of the core engine driving the fan at this time CF1 and the bypass ratio B2, and measure the surge point parameters.

[0075] d) If the core engine-driven fan still loses stability first when the guide vane angle and bypass ratio reach the limit boundary, it indicates that the pressure distortion sensitivity coefficient of the compressor in this system is zero, and the distortion flow test will no longer be carried out;

[0076] e) Keep the adjustment laws of β CF0 、β CF1 、B2 unchanged, carry out the distortion flow test, and measure the flow-pressure ratio characteristics of the compressor and the comprehensive distortion index at the compressor inlet

[0077] In the distortion flow test in the above embodiments, when measuring the surge point parameters, in order to obtain the surge point flow rate and pressure ratio of the CDFS and the compressor respectively, and the corresponding inlet comprehensive distortion index, it is necessary to make the CDFS and the compressor become the first unstable components respectively. Therefore, specific measures are needed to change the matching between the CDFS and the compressor. The measures described include changing the inlet guide vane angle of the CDFS, the inlet guide vane angle of the compressor, and the bypass ratio.

[0078] In some embodiments, the pressure distortion sensitivity coefficient is an important index used to characterize the ability of the compression system to resist inlet pressure distortion. The pressure distortion sensitivity coefficient of the compression system described in the present invention includes 3 parameters: the total pressure distortion sensitivity coefficient α Z of the compression system, the pressure distortion sensitivity coefficient α CF of the CDFS, and the pressure distortion sensitivity coefficient α C of the compressor. The data required to calculate these 3 parameters include: inlet comprehensive distortion index, uniform flow characteristics, distortion flow characteristics, and operating line. Among them, the inlet comprehensive distortion index, uniform flow characteristics, and distortion flow characteristics are obtained from the above tests. The operating line is obtained from the engine performance matching and will not be described in the present invention. The operating point described in the present invention is the intersection of the operating line and the characteristic line. Schematic diagrams of uniform flow, distortion flow characteristics, and operating line are shown in Figure 3 , the abscissa W c represents the converted flow rate, the ordinate π represents the total pressure ratio, ① uniform flow characteristic surge point ② uniform flow operating point ③ distortion flow characteristic surge point ④ distortion flow operating point.

[0079] The calculation steps of the pressure distortion sensitivity coefficient in S3 are as follows:

[0080] S3.1: Calculate the stability margin SM under uniform inlet conditions un i

[0081] SM uni =(π1 / W c1 ) / (π2 / W c2 ) -1

[0082] where, π1 is the surge point pressure ratio of the uniform flow characteristic, W c1The flow rate converted at the surge point for the uniform flow characteristics; π2 is the pressure ratio at the operating point of the uniform flow, W c2 The flow rate converted at the operating point of the uniform flow;

[0083] S3.2: Calculate the stability margin SM under distorted inlet conditions uni

[0084] SM dis =(π3 / W c3 ) / (π4 / W c4 ) -1

[0085] where, π3 is the pressure ratio at the surge point of the distorted flow characteristics, W c3 is the flow rate converted at the surge point of the distorted flow characteristics, π4 is the pressure ratio at the operating point of the distorted flow, W c4 is the flow rate converted at the operating point of the distorted flow;

[0086] S3.3: Calculate the pressure distortion sensitivity coefficient α

[0087]

[0088] where, is the inlet comprehensive distortion index.

[0089] In the above embodiment, when calculating the pressure distortion sensitivity coefficient α of the compression system Z , SM uni and SM dis are calculated from the working line and characteristics of the compression system according to S3.1 and S3.2 respectively, and the corresponding is the CDFS inlet comprehensive distortion index When calculating the pressure distortion sensitivity coefficient α of the CDFS CF , SM uni and SM dis are calculated from the working line and characteristics of the CDFS according to S3.1 and S3.1 respectively, and the corresponding is the CDFS inlet comprehensive distortion index When calculating the pressure distortion sensitivity coefficient α of the compressor C , SM uni and SM dis are calculated from the working line and characteristics of the compressor according to S3.1 and S3.1 respectively, and the corresponding is the compressor inlet comprehensive distortion index

[0090] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A method for determining the pressure distortion sensitivity coefficient of a compression system, characterized in that, The compression system includes a core engine-driven fan and a compressor, and the method includes the following steps: S1: Design the distortion generating device; S2: Place the core engine-driven fan and the compressor in the compression system, and respectively obtain the aerodynamic performance parameters of the compression system, the core engine-driven fan in the compression system, and the compressor in the compression system; S3: Calculate the sensitivity coefficients of the compression system, the core engine-driven fan, and the compressor respectively based on the aerodynamic performance parameters obtained in S2; The steps for obtaining the aerodynamic performance of the compression system are as follows: a) Keep the original adjustment law unchanged, and the adjustment law includes the CDFS inlet guide vane angle β CF0 , the compressor inlet guide vane angle β C0 and the bypass ratio B0; b) Conduct a uniform flow test to measure the aerodynamic performance parameters of the compression system; c) After inserting the distortion generating device into the intake passage, conduct a distorted flow test to measure the flow-pressure ratio characteristics of the compression system and the comprehensive distortion index at the inlet of the compression system. The steps for obtaining the aerodynamic performance of the core engine-driven fan in the compression system are as follows: A: Keep the original regulation law unchanged, conduct a uniform flow test, and measure the flow rate-pressure ratio characteristics of the core engine-driven fan; B: During the measurement of the surge point parameters, if the compressor becomes unstable first, close the inlet guide vane angle of the compressor by 0.5°, and at the same time reduce the bypass ratio by 0.1B0; C: Repeat step B) until the core engine driven fan first becomes unstable, and record the compressor inlet guide vane angle β C1 and the bypass ratio B1, and measure the surge point parameters; D: If the compressor is still unstable first when the guide vane angle and the bypass ratio reach the limit boundary, it indicates that the pressure distortion sensitivity coefficient of the core engine-driven fan in this system is zero, and the distorted flow test is no longer carried out; E: Maintain β CF0 , β C1 , keep the adjustment rules of β, B1 unchanged, conduct a distorted flow test, and measure the flow rate-pressure ratio characteristics of the core engine-driven fan and the comprehensive distortion index at the inlet of the core engine-driven fan The steps for obtaining the aerodynamic performance of the compressor in the compression system are as follows: a) Keep the original regulation law unchanged, conduct a uniform flow test, and measure the flow rate-pressure ratio characteristics of the compressor; b) During the measurement of the surge point parameters, if the core engine-driven fan becomes unstable first, close the inlet guide vane angle of the core engine-driven fan by 0.5°, and at the same time increase the bypass ratio by 0.1B0; c) Repeat step b) until the compressor first becomes unstable, and record the angle β of the inlet guide vane of the core engine driving the fan at this time CF1 and the bypass ratio B2, and measure the surge point parameters; d) If the core engine-driven fan is still unstable first when the guide vane angle and the bypass ratio reach the limit boundary, it indicates that the pressure distortion sensitivity coefficient of the compressor in this system is zero, and the distorted flow test is no longer carried out; e) Maintain β CF0 and β CF1 while keeping the adjustment laws of B2 unchanged, conduct a distorted flow test, and measure the flow-pressure ratio characteristics of the compressor and the comprehensive distortion index at the compressor inlet 2. The method for determining the pressure distortion sensitivity coefficient of a compression system according to claim 1, characterized in that, The distortion generating device in S1 is a sector-shaped plug structure.

3. The method for determining the pressure distortion sensitivity coefficient of a compression system according to claim 2, characterized in that, The sector angle θ of the sector-shaped plug structure is 150° - 180°; the thickness of the sector-shaped plug is 10 - 20 mm; the insertion depth L of the sector-shaped plug is 0.1D - 0.5D, where D is the diameter of the air inlet channel of the compression system.

4. The method for determining the pressure distortion sensitivity coefficient of a compression system according to claim 3, characterized in that, The plug is installed 2D - 3D upstream of the inlet of the core engine-driven fan during the test.

5. The method for determining the pressure distortion sensitivity coefficient of a compression system according to claim 1, characterized in that, In the uniform flow test, when measuring the aerodynamic performance parameters of the compression system, each characteristic line has no less than 6 points, and it is ensured that a complete characteristic line can be formed.

6. The method for determining the pressure distortion sensitivity coefficient of a compression system according to claim 1, characterized in that, The calculation steps for the pressure distortion sensitivity coefficient in S3 are as follows: S3.1: Calculate the stability margin SM under uniform intake conditions uni SM uni =(π1 / W c1 ) / (π2 / W c2 ) -1 Among them, π1 is the pressure ratio at the surge point of the uniform flow characteristic, and W c1 is the converted flow rate at the surge point of the uniform flow characteristic; π2 is the pressure ratio at the operating point of the uniform flow, and W c2 is the converted flow rate at the operating point of the uniform flow; S3.2: Calculate the stability margin SM under distorted intake conditions uni SM dis = (π3 / W c3 ) / (π4 / W c4 ) -1 Among them, π3 is the pressure ratio at the surge point of the distorted flow characteristic, and W c3 is the converted flow rate at the surge point of the distorted flow characteristic, π4 is the pressure ratio at the operating point of the distorted flow, and W c4 is the converted flow rate at the operating point of the distorted flow; S3.3: Calculate the pressure distortion sensitivity coefficient α Among them, is the import comprehensive distortion index.

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