Method, system, device and readable storage medium for evaluating the impact of S-shaped inlet on compressor stability

Abstract

The present disclosure provides a method for evaluating the influence of an S-shaped inlet on compressor stability, comprising: constructing an X-Y coordinate system with the velocity circulation Γ of the aerodynamic inlet section as the Y-axis and the dimensionless parameter combination of the aerodynamic inlet section as the X-axis; adjusting the combination of the dimensionless parameter combination so that the scatter plot of the velocity circulation in the X-Y coordinate system is regularly distributed; obtaining the adjusted combination of the dimensionless parameter combination to characterize the model relationship between the flow field distortion intensity and the inlet geometry; and simulating and restoring the total pressure field of the aerodynamic inlet section based on the dimensionless parameters. The present disclosure solves the technical problem of the inability to effectively connect the distorted flow field with the inlet geometry, and solves the unique description of the degree of distortion. The obtained parameters can be used as inlet condition inputs for an analysis model of the influence of the inlet on engine stability.

Description

Technical Field

[0001] The present invention relates to the technical field related to flight simulation, and in particular to a method, system, device and readable storage medium for evaluating the influence of an S-shaped air inlet on compressor stability. Background Art

[0002] The demands placed on military aircraft survivability in modern air combat environments are driving the continuous development of stealth designs. The complex curved geometry of the S-shaped inlet allows radar waves to be attenuated multiple times on the inlet's inner wall, effectively obscuring the engine's visible area and significantly improving the aircraft's stealth performance. However, this inlet flow form, with its complex geometry and large curvature, may produce boundary layer separation within the inlet, and flow characteristics such as total pressure distortion and swirl distortion at the downstream engine inlet, seriously affecting the engine's steady-state and dynamic characteristics. In addition to total pressure loss and reduced thrust, the potential adverse effects include insufficient stability margin for the aircraft engine, leading to stall and surge, seriously endangering flight safety and engine life.

[0003] After connecting to the S-shaped inlet, the typical intake condition of the aircraft engine presents an inlet velocity field with not only axial flow, but also lateral secondary flow in the plane perpendicular to the axial direction, namely swirl distortion. For the method of evaluating the degree of this intake unevenness, the existing technology generally adopts the method of numerical simulation and experimental measurement, and uses the flow field information obtained by numerical calculation and experimental measurement for analysis, and calculates a series of index parameters (SI series parameters) to characterize the swirl position and swirl intensity. However, the existing technology has the following problems: First, the existing technology can only rely on the swirl angle obtained by numerical calculation or experimental measurement to evaluate the distortion intensity, and cannot establish the connection between the distortion intensity and the inlet geometry. Second, the distortion degree index obtained by the existing technology is not uniquely descriptive, that is, only knowing the quantity of this parameter cannot restore the specific distortion spectrum and swirl form. Third, the existing technology cannot be applied to the subsequent analysis model of the influence of the inlet on the engine stability. Summary of the Invention

[0004] To address the problems in existing technologies, such as the inability to establish a relationship between distortion intensity and inlet geometry, the lack of a unique descriptive value for distortion indicators, and the inability to apply to subsequent inlet impact analysis models, the present disclosure provides a method for evaluating the impact of an S-shaped inlet on compressor stability, including:

[0005] An XY coordinate system is constructed with the velocity circulation Γ of the aerodynamic inlet section as the Y-axis and the dimensionless parameter combination of the aerodynamic inlet section as the X-axis.

[0006] By adjusting the combination of dimensionless parameters, the scatter plot of the velocity circulation in the XY coordinate system is regularly distributed; the regular distribution is the regular distribution of the scatter plot of the velocity circulation Г in the XY coordinate system showing linear regression.

[0007] A combination of the adjusted dimensionless parameter combinations is obtained to characterize the model relationship between the flow field distortion intensity and the inlet geometry.

[0008] This disclosure, designed for intake ducts with actual geometry, can directly derive index parameters with a one-to-one mapping relationship that characterize the distortion characteristics of complex intake ducts. This addresses the existing issues of being unable to establish a link between distortion intensity and intake duct geometry, and the lack of a unique descriptive quality indicator.

[0009] This disclosure provides an exemplary method for obtaining the velocity circulation G, comprising: taking the upper right or upper left quarter circle of the aerodynamic inlet cross section as the calculation domain, constructing a closed curve based on the locations of experimental measurement points, and performing an approximate calculation of the velocity circulation to obtain the velocity circulation G. The experimental measurement points are experimental measurement points on the inlet cross section that meet industry standards while the compressor is operating.

[0010] By observing the change process of the swirl pattern at the aerodynamic inlet section (hereinafter referred to as the AIP section), it can be found that the key to measuring the change of its flow field pattern is to measure the evolution of the secondary flow in the upper semicircle. Therefore, the present disclosure adopts the strategy of "upper and lower separation, left and right averaging" to solve the limitations of existing technical indicators. Take the upper semicircle of the AIP section for calculation, take the left and right averages to reduce the asymmetric accidental error of the steady flow field calculation, and obtain the calculation domain of the upper right 1 / 4 circle. Construct a closed curve according to the position of the experimental measuring point, and perform an approximate calculation of the velocity circulation. Its physical significance is that it can characterize the vortex intensity in the upper 1 / 4 circle. The calculation results of the secondary flow velocity cloud map show that the vertical velocity component near the center of the pipe is relatively linear, and the error will not be too large when using this method. The velocity circulation can be calculated for other measuring points using interpolation methods such as linear interpolation.

[0011] The present disclosure exemplarily provides a dimensionless parameter, including: dimensionless offset [e], dimensionless axial length [L], dimensionless expansion [d2], wherein:

[0012]

[0013] Where, e is the aerodynamic inlet section offset, L is the aerodynamic inlet section length, d1 is the inlet duct inlet diameter, and d2 is the inlet duct outlet diameter.

[0014] The dimensionless offset [e], dimensionless axial length [L], and dimensionless expansion [d2] provided by the present disclosure are more convenient in the subsequent data processing stage and can be applied to the subsequent analysis model of the influence of the intake duct on engine stability.

[0015] The present disclosure exemplarily provides a dimensionless parameter combination, which is: [e] k [L] m [d2] n Where k ranges from 1 to 4, m ranges from -3 to 2, and n ranges from 1 to 4. This dimensionless number combination can be used as a criterion for the swirl mode.

[0016] The present disclosure provides a method for evaluating the influence of an S-shaped air inlet on compressor stability, further comprising: simulating and restoring the total pressure field of the aerodynamic inlet section based on dimensionless parameters.

[0017] The present disclosure exemplarily provides a method for simulating and restoring the total pressure field of an aerodynamic inlet section, comprising:

[0018] (1) Based on the range characteristics of the low-pressure area, a family of longitude and latitude curves are defined in the flow channel; wherein the range characteristics of the low-pressure area are: based on the range characteristics of the low-pressure area of ​​the inlet cross section measured in the industry standard experiment.

[0019] (2) According to the characteristics of the total pressure cloud map, the low-pressure characteristic points of the upper low-pressure area and the lower low-pressure area are selected, and the total pressure value at the low-pressure characteristic point is used as a reference value to determine the total pressure deficit intensity of the upper low-pressure area and the lower low-pressure area respectively;

[0020] (3) Selecting the horizontal and vertical control lines, thus giving the total pressure distribution law and obtaining the total pressure value of each control point;

[0021] (4) The total pressure value of each control point is mapped back to the longitude and latitude system, and the cloud map is drawn by interpolation to obtain the simulated and restored total pressure field of the aerodynamic inlet section.

[0022] This disclosure uses key evaluation indicators based on the total pressure distortion characteristics of the AIP section, namely the changes in the influence range and intensity of the upper and lower low total pressure zones, to directly simulate and restore the total pressure field of the AIP section. This solves the technical problem of existing technologies that distortion degree indicators are not uniquely descriptive.

[0023] The present disclosure also provides a system for evaluating the impact of an S-shaped inlet on compressor stability, comprising an input module, an analysis module, an output module, and a storage module. The input module receives information from outside the system and then inputs it into the analysis module. The analysis module analyzes and processes the input information using the aforementioned method for evaluating the impact of an S-shaped inlet on compressor stability to generate output information. The output module receives the output information from the analysis module and outputs it to the outside of the system. The output information includes at least information about the gravity torque and friction torque of the outer frame of a horizontal three-axis hydraulic flight turntable. The storage module is used to store preset information to be stored.

[0024] The present disclosure also provides a device for evaluating the effect of an S-shaped inlet on compressor stability, comprising a memory and a processor, wherein the memory stores a computer program executable on the processor. When the processor executes the program, the steps of the method for evaluating the effect of an S-shaped inlet on compressor stability are implemented.

[0025] The present disclosure also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps in the above-mentioned method for evaluating the influence of the S-shaped inlet on the stability of the compressor are implemented.

[0026] The present disclosure has at least one of the following advantages:

[0027] 1. The present disclosure solves the technical problem that the distorted flow field and the inlet duct geometry cannot be effectively linked, and uses a partition calculation method to establish a model relationship between the flow field distortion intensity and the inlet duct geometry.

[0028] 2. The present disclosure solves the technical problem of uniquely describing the degree of distortion. Not only can the index parameters proposed by the present invention measure the distortion intensity, but the specific distortion spectrum and vortex form can also be effectively restored.

[0029] 3. The parameters obtained in this disclosure can be used as the inlet condition input of the analysis model of the influence of the intake duct on the engine stability, which greatly simplifies the model prediction process and saves costs, and can directly explore the stability characteristics of the overall system composed of the intake duct and the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a diagram of the complex air inlet structure of an advanced aircraft.

[0031] Figure 2 for Figure 1 Diagram of swirl distortion and boundary layer separation in the complex S-shaped inlet of an advanced aircraft.

[0032] Figure 3 Schematic diagram of the numerical integration path for the upper 1 / 4 circle.

[0033] Figure 4 Comparison of cloud maps with different offset curls.

[0034] Figure 5 It is the velocity circulation diagram of the upper 1 / 4 circle secondary flow.

[0035] Figure 6 It is a graph of the longitude and latitude of the flow channel.

[0036] Figure 7 A schematic diagram is given for the total pressure distribution law on the control line.

[0037] Figure 8This is a mapping diagram between each control line and control point.

[0038] Figure 9 Coordinate diagram of recommended values ​​for the adjustment variable k.

[0039] Figure 10 When [e] = 1.3, [L] = 6, and [d2] = 1.30, the total pressure reconstruction comparison diagram of the example is shown. DETAILED DESCRIPTION

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

[0041] Example 1

[0042] by Figure 1 Based on the complex inlet of the advanced aircraft shown in the figure, the swirl distortion and boundary layer separation of the S-shaped inlet are shown in the figure. Figure 2 The method for evaluating the influence of the S-shaped inlet on the compressor stability is used for analysis, which includes the following steps:

[0043] An XY coordinate system is constructed with the velocity circulation Γ of the aerodynamic inlet section as the Y-axis and the dimensionless parameter combination of the aerodynamic inlet section as the X-axis.

[0044] By observing the change process of the swirl pattern in the AIP section, it can be found that the key to measuring the change of its flow field pattern lies in measuring the evolution of the secondary flow in the upper semicircle. Therefore, it can be considered that a solution to the limitations of the SI series of indicators is to adopt the strategy of "upper and lower separation, left and right averaging". Take the upper semicircle of the AIP section for calculation, and take the average value of the left and right to reduce the asymmetric accidental error of the steady flow field calculation, and obtain the calculation domain of the upper right 1 / 4 circle. Construct a closed curve based on the position of the experimental measurement point, and perform an approximate calculation of the velocity circulation. Figure 3 The figure shows the integration path. Its physical significance lies in characterizing the vortex intensity within the upper quarter of the circle. Since the data for point 12 is not distributed at a single measurement point, it can be interpolated using data from adjacent measurement points above and below. The secondary flow velocity contour shows good linearity for the vertical velocity component near the center of the pipe, and this method should not produce excessive errors. Velocity circulation can be calculated for other measurement points using interpolation methods such as linear interpolation.

[0045] By adjusting the combination of dimensionless parameters, the scatter plot of velocity circulation in the XY coordinate system is regularly distributed.

[0046] The secondary flow velocity curl cloud diagrams of different offset groups are compared, such as Figure 4As shown. In the figure, the dimensionless offset [e] from left to right is 0.8, 1.1, and 1.3 respectively. It can be seen that there is a significant change in the intensity of the corresponding pair of vortices above, which indirectly reflects the physical basis for the velocity circulation to estimate the flow field form. Among them, the dimensionless offset [e], dimensionless axial length [L], and dimensionless expansion [d2] are more convenient in the subsequent data processing stage. They are defined as the offset e, length L, and the ratio of the inlet outlet diameter d2 to the inlet inlet diameter d1 to make them dimensionless. Among them:

[0047]

[0048] Where, e is the aerodynamic inlet section offset, L is the aerodynamic inlet section length, d1 is the inlet duct inlet diameter, and d2 is the inlet duct outlet diameter.

[0049] A combination of the adjusted dimensionless parameter combinations is obtained to characterize the model relationship between the flow field distortion intensity and the inlet geometry.

[0050] Adjust the combination of independent variables taken from the horizontal axis to make the velocity circulation scatter plot as regular as possible, and we can get Figure 5 The upper quarter circle secondary flow velocity circulation diagram is shown. The number of independent variable combinations is [e] 3 [L] -2 [d2] 2 , it can be found that the velocity circulation has a sudden increase near the horizontal axis of 0.1, which means that the two-pair vortex characteristics are significantly enhanced. The cloud map and vector field map show that the groups with horizontal coordinates greater than 0.1 in the effective case all have significant two-pair vortex characteristics, while the groups with horizontal coordinates less than 0.1 have no such characteristics or the characteristics are not obvious. From the perspective of the vertical axis, the velocity circulation is greater than 0.15m 2 / s groups all have two pairs of vortex characteristics, less than 0.15m 2 / s group has significant vortex characteristics. Therefore, from a geometric point of view, the dimensionless number [e] 3 [L] -2 [d2] 2 =0.10 is a critical point; from the perspective of experimental measurement, the velocity circulation Г=0.15m 2 / s is a critical point.

[0051] The sources of the upper counter-vortex were compared between the two groups with dimensionless offsets of 0.8 and 1.3. In the early stage of the development of the recirculation zone, when the boundary layer separation begins to occur near the upper pipe wall, the secondary flow field in the cross section will produce a certain static pressure gradient due to the curvature. As the recirculation zone develops, the low-speed and high-pressure air mass in the recirculation zone forces the secondary flow streamlines to bend downward. A local high static pressure area will be generated at the edge of the pipe wall near the recirculation zone, and the reason for its generation may be related to the stagnation effect. The relative size of the static pressure in the high static pressure area here and the static pressure inside the recirculation zone is very critical to affecting the downstream flow field form. When the offset is large, at a certain axial position, the high static pressure area outside the recirculation zone is strong enough to push the near-wall fluid into the interior of the recirculation zone and roll up the counter-vortex, and then gradually move downward in the process of decreasing flow channel curvature, thereby generating the counter-vortex downstream of the recirculation zone. On the contrary, if the offset is small enough so that the static pressure inside the recirculation zone is sufficient to push the near-wall fluid to penetrate deeper into the outside of the recirculation zone and extend toward the lower half of the pipe wall, a strong counter-vortex will not be generated in the upper half of the flow channel, but the counter-vortex in the lower half will be strengthened.

[0052] From this, it can be inferred that the flow field form can be evaluated by the ratio of the static pressure near the recirculation zone to the static pressure within the recirculation zone. The larger the ratio, the easier it is for the boundary layer fluid to develop upward and produce two pairs of vortices; conversely, the easier it is for the boundary layer fluid to develop downward and produce one pair of vortices. The static pressure near the recirculation zone can be approximately reflected by the curvature of the flow channel centerline, and the curvature of the centerline is approximately the same as [e] 1 [L] -2 The static pressure inside the recirculation zone is directly proportional to the axial velocity of the recirculation. The larger the cross-sectional recirculation range, the stronger the axial velocity and the lower the static pressure. The recirculation zone is almost positively correlated with the expansion area of ​​the flow channel, and its change trend with the offset is that it first increases rapidly and then tends to be gentle. Therefore, [e] x [d2] 2 It is negatively correlated with the static pressure inside the recirculation zone, where the exponent of the offset is an unknown positive value. Considering these two factors, it can be concluded that the overall form of the flow field should be approximately the same as [e] (x+1) [L] -2 [d2] 2 correlation, where the bias index is a value greater than 1.

[0053] The results of the semi-quantitative analysis at this physical level also show that when the offset is large enough, the effect of the offset on the static pressure inside the recirculation zone is very limited and far below the cubic growth rate. This means that with the velocity circulation Г as the vertical axis, the dimensionless number combination [e] 3 [L] -2 [d2] 2 The scatter plot with the horizontal axis should flatten out when the offset is large enough. Furthermore, from the above analysis, it is not difficult to see that when the offset is large enough, the offset exponent in the dimensionless number combination should be appropriately reduced to 1-2, otherwise it will be difficult to make the scatter plots of different offset groups fall near the same trend line.

[0054] It can be seen that the present disclosure can solve the technical problem that the distorted flow field and the inlet duct geometry cannot be effectively connected, and a model relationship between the flow field distortion intensity and the inlet duct geometry is established by using a partition calculation method.

[0055] Based on dimensionless parameters, the total pressure field of the aerodynamic inlet section is simulated and restored.

[0056] According to the range characteristics of the low-pressure area, two families of curves are delineated in the flow channel. The warp curve family is an arc with its center on the horizontal midline and passing through the upper and lower vertices of the flow channel. For any warp curve, given a percentage, a point can be drawn on the curve so that the ratio of the arc length above the point to the total arc length of the warp curve is equal to this percentage value. Keeping this percentage unchanged, all the points drawn on the warp curve are connected into a curve to obtain a weft curve. Draw a weft curve for any percentage to obtain a weft curve family. The warp and weft curve families are as follows Figure 6 .

[0057] The latitude curve passing through the midpoint of the upper and lower total pressures on the vertical symmetry line is considered the low-pressure boundary. The upper side of the upper latitude curve is considered the upper low-pressure influence zone, and the lower side of the lower latitude curve is considered the lower low-pressure influence zone. Based on the characteristics of the total pressure contour, the midpoints of the two radial positions and their nearest wall points are used as the upper and lower low-pressure characteristic points, respectively. The total pressure at the low-pressure characteristic points is used as a reference value to determine the total pressure deficit intensity of the upper and lower low-pressure zones, respectively.

[0058] Select transverse and longitudinal control lines. Since the steady flow field exhibits bilateral symmetry, the longitudinal control line is the axis of symmetry, i.e., the meridian passing through the center of the circular cross-section. The midpoint between the upper and lower total pressure midpoints is chosen, and the latitude curve passing through this midpoint serves as the transverse control line. These two control lines serve to define the total pressure distribution and characterize the total pressure characteristics at key points.

[0059] For the longitudinal control line, a total pressure distribution law can be given inside the upper low-pressure influence area, inside the lower low-pressure influence area, and in the middle high-pressure influence area. These given total pressure distribution laws can be given, verified, and checked through numerical calculation results, and finally a more general form can be selected. Figure 7 (a) is a simpler form.

[0060] For the lateral control line, another total pressure distribution law can be given, which not only allows the total pressure in the near-wall area to change continuously, but also allows the central area of ​​the pipe flow to have a high total pressure area of ​​sufficient range. Due to the symmetry of the flow field, only the flow field corresponding to the right semicircle needs to be considered. Figure 7 (b) is a simpler form. Note that you can change Figure 7 The distribution law in is used to change the final constructed total pressure field. Figure 7The horizontal axis values ​​in (a) and (b) are the horizontal and vertical coordinate values ​​after mapping to the rectangular system.

[0061] The longitude and latitude curves outside the low-pressure zone are mapped into longitudinal and transverse straight lines in a rectangular coordinate system. Control points are determined based on the intersection of the two lines. The total pressure values ​​at each control point are then determined using a given fitting rule in the rectangular system. This can then be mapped back to the longitude and latitude system, and a cloud diagram can be created using a specific interpolation method to obtain the simulated total pressure field.

[0062] In this example, for the right semicircular flow field, a total of 4 longitude curves and 5 latitude curves are used to determine the control points, such as Figure 8 . The coordinates of the intersection points of the 5 latitude curves with the longitudinal symmetry line (dimensionless using the radius) are (1+Y1) / 2, Y1, (Y1+Y2) / 2, Y2, and (Y2+1) / 2 from top to bottom. The dimensionless coordinates of the intersection points of the 4 longitude curves with the transverse symmetry line (dimensionless using the radius) are 0, 1 / 3, 2 / 3, and 1 from left to right.

[0063] Figure 8 In the rectangular system, the horizontal axis is represented by u and the vertical axis is represented by v. Figure 7 , the total pressure at 10 control points on the u-axis or v-axis is determined, such as Figure 8 As shown by the red, blue and black points. For all points with v = 1 or v = -1, they are actually the same as the upper vertex or lower vertex, and the total pressure is also determined. There are still 6 undetermined control points in the first quadrant and 6 undetermined control points in the fourth quadrant. They are neither on the u axis nor on the v axis, as shown in Figure 8 Indicated by the green dot.

[0064] The total pressure reconstruction empirical function adopted in this example is shown as follows:

[0065]

[0066] Where k is the adjustment variable, Δpt,max is the relative value of the total pressure difference between the upper and lower low total pressure areas, which can be approximated as the ratio of the total pressure difference between the upper and lower vertices to the maximum total pressure difference of the entire cross section. In the calculation, the six points in the first quadrant and the six points in the fourth quadrant are calculated separately. The empirically recommended values ​​for different geometric features are as follows: Figure 9 shown. Figure 9 The k1 curve is the recommended k value for the first quadrant, and the k4 curve is the recommended k value for the fourth quadrant. Figure 9 It is obvious that the k1 value is the dimensionless number [e] 3 [L] -2 [d2] 2 The sudden change near 0.10 reflects the change in the total pressure distortion pattern of the upper low-pressure area. After determining the total pressure of all control points, two-dimensional interpolation is performed to obtain the reconstructed total pressure distribution of the AIP section.

[0067] The total pressure mode simulation is carried out for the case group with geometric independent variables [e], [L], [d2] as (1.3, 6, 1.30), and compared with the numerical calculation results. Figure 10 The dimensionless number corresponding to this group is 0.103. The comparison shows that this method can basically characterize the total pressure distortion characteristics of the large offset group with a dimensionless offset level of 1.3.

[0068] It can be seen that the present disclosure can solve the technical problem of uniquely describing the degree of distortion. Not only can the index parameters proposed by the present invention measure the distortion intensity, but the specific distortion spectrum and swirl form can also be effectively restored.

[0069] In addition, the dimensionless parameters obtained in the present disclosure can be used as the inlet condition input of the analysis model of the influence of the intake duct on the engine stability, which greatly simplifies the model prediction process and saves costs, and can directly explore the stability characteristics of the overall system composed of the intake duct and the engine.

[0070] Example 2

[0071] A system for evaluating the influence of an S-shaped inlet on compressor stability includes an input module, an analysis module, an output module, and a storage module. The input module receives information from outside the system and then inputs the information to the analysis module. Figure 1 The complex air inlet of the advanced aircraft shown is used as a basis, and the input information includes the data measured at the experimental measurement points in Example 1.

[0072] The analysis module analyzes and processes the received input information using the method for evaluating the impact of an S-shaped inlet on compressor stability described in Example 1 to generate output information. The output module receives the output information from the analysis module and outputs it to the outside of the system. The output information includes at least information about the gravity moment and friction moment of the outer frame of the horizontal three-axis hydraulic flight turntable. The storage module is used to store predetermined information to be stored.

[0073] Example 3

[0074] A device for evaluating the influence of an S-shaped inlet on the stability of a compressor comprises a memory and a processor, wherein the memory stores a computer program that can be run on the processor. Figure 1 Based on the complex air inlet of the advanced aircraft shown, when the processor executes the program, the steps of the method for evaluating the influence of the S-shaped air inlet on the stability of the compressor in Example 1 are implemented.

[0075] Example 4

[0076] A computer readable storage medium having a computer program stored thereon. Figure 1Based on the complex air inlet of the advanced aircraft shown, the computer program, when executed by a processor, implements the steps of the method for evaluating the influence of the S-shaped air inlet on the stability of the compressor in Example 1.

[0077] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A system for evaluating the effect of an S-shaped inlet on compressor stability, comprising an input module, an analysis module, an output module, and a storage module; characterized in that: The input module receives information from outside the system and inputs the information to the analysis module. The analysis module analyzes and processes the input information based on the received input information using a method for evaluating the impact of the S-shaped inlet on compressor stability to obtain output information. The output module receives the output information from the analysis module and outputs the information outside the system. The output information at least includes information on the gravity torque and friction torque of the outer frame of the horizontal three-axis hydraulic flight turntable. The storage module is used to store preset information to be stored. Methods for evaluating the effect of S-shaped inlets on compressor stability include: The velocity circulation Γ of the aerodynamic inlet section is used as the Y axis, and the dimensionless parameter combination of the aerodynamic inlet section is used as the X axis to construct an XY coordinate system. By adjusting the combination of dimensionless parameters, the scatter plot of velocity circulation in the XY coordinate system is regularly distributed. Obtaining a combination of the adjusted dimensionless parameter combinations to characterize a model relationship between flow field distortion intensity and inlet duct geometry; The combination of the adjusted dimensionless parameter combinations is obtained to characterize the model relationship between the flow field distortion intensity and the inlet geometry, including: According to the adjusted dimensionless parameters, the total pressure field of the aerodynamic inlet section is simulated and restored; The methods for simulating and restoring the total pressure field of the aerodynamic inlet section include: According to the range characteristics of the low-pressure area, the longitude and latitude curve families are delineated in the flow channel; According to the characteristics of the total pressure cloud map, the low-pressure characteristic points of the upper low-pressure area and the lower low-pressure area are selected, and the total pressure value at the low-pressure characteristic point is used as a reference value to determine the total pressure deficit intensity of the upper low-pressure area and the lower low-pressure area respectively; Select the horizontal and vertical control lines to give the total pressure distribution law and obtain the total pressure value of each control point; The total pressure value of each control point is mapped back to the longitude and latitude system, and the cloud map is drawn by interpolation to obtain the simulated and restored total pressure field of the aerodynamic inlet section.

2. The system for evaluating the influence of an S-shaped inlet on compressor stability according to claim 1, characterized in that: The upper right or upper left quarter circle of the aerodynamic inlet section is taken as the calculation domain. A closed curve is constructed according to the position of the experimental measuring points, and the velocity circulation Γ is obtained by approximate calculation of the velocity circulation.

3. The system for evaluating the influence of an S-shaped inlet on compressor stability according to claim 1, characterized in that: The dimensionless parameters include: dimensionless offset [e], dimensionless axial length [L], dimensionless expansion [d2], where: Where, e is the aerodynamic inlet section offset, L is the aerodynamic inlet section length, d1 is the inlet duct inlet diameter, and d2 is the inlet duct outlet diameter.

4. The system for evaluating the influence of an S-shaped inlet on compressor stability according to claim 3, characterized in that: The dimensionless parameter combination is: [e] k [L] m [d2] n ; Among them, the value of k is 1 to 4, the value of m is -3 to 2, and the value of n is 1-4.

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