Variable geometry turbine end region configuration method

Abstract

The invention discloses a variable geometry turbine end region configuration method, which comprises the following steps of: firstly, rotating by utilizing extracted discrete points on the end surfaces of a blade tip and a blade root to obtain the discrete points on the end surfaces of the blade tip and the blade root after rotation, and densifying the extracted discrete points and fitting into curved surfaces of a casing and a hub; and screening out rotated discrete points outside the end areas of the casing and the hub by using the fitted curved surfaces of the casing and the hub. And obtaining upper and lower boundaries of the cartridge receiver and the hub end area through the screened discrete points, and constructing lower boundary curved surfaces of the cartridge receiver and the hub end area, transition curved surfaces of upper and lower boundary curves and upper boundary curved surfaces of the end area by using the upper and lower boundaries and the original cartridge receiver and hub end wall. And finally, sewing the curved surfaces to obtain a new variable geometry turbine case and hub end region configuration. Compared with a variable geometry turbine of an original end area, the end area configuration technology has the advantages that the flow loss caused by gap leakage flow of the end area is obviously reduced, the efficiency of the guide vane at each angle is improved, and the aerodynamic performance of the variable geometry turbine is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of turbines, and in particular relates to a variable geometry turbine end zone configuration method. Background Art

[0002] After the traditional engine design is completed, the main working cycle parameters of the design point are determined. The engine can only guarantee the best performance at the design point, and cannot achieve the best performance in other conditions within the working envelope. The variable cycle engine achieves the change of the thermodynamic cycle by changing the flow channel shape and geometric dimensions of the core section and adjusting the thermodynamic cycle parameters, thereby ensuring that the engine is in the best performance state under various flight conditions. It can give full play to the performance potential of the engine in a wider flight envelope, which is the development direction of high-performance aircraft engines in the future. Variable cycle engines have huge superior potential compared to conventional engines, and can provide fighters with better maneuverability and supersonic cycle capabilities. For fighters, the most attractive variable cycle engine solution is variable geometry turbine technology.

[0003] Variable geometry turbine technology is to change the flow capacity of the turbine by rotating the guide vanes and adjusting the guide vane throat area. It plays an important role in adjusting flow, controlling thrust, and adjusting the engine operating point in variable cycle engines. It is an indispensable and important component of variable cycle engines. As a key technology in variable cycle engines, variable geometry turbine plays an important role in improving the performance of engines under non-design conditions. Variable geometry turbine design technology and aerodynamic performance have always been an important topic in the field of turbomachinery research.

[0004] In order to ensure that the adjustable guide vanes of the variable geometry turbine can rotate unhindered within the specified angle range, a certain gap needs to be left between the guide vanes and the end areas of the casing and hub. If the gap is too small, the guide vanes will contact the casing and hub end walls during rotation and get stuck. If the gap is too large, leakage flow will occur in the end area gap, causing the turbine efficiency to decrease and having a certain impact on the aerodynamic performance of the turbine. This requires a suitable end area configuration technology to meet the requirements of both geometric structure and aerodynamic performance. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a variable geometry turbine end area configuration method. First, the extracted discrete points of the blade tip and blade root end surface are rotated to obtain the discrete points of the blade tip and blade root end surface after rotation within a certain range, and the extracted discrete points of the casing and hub are encrypted and fitted into casing and hub surfaces. The fitted casing and hub surfaces are used to filter out the rotated discrete points outside the casing and hub end areas. The upper and lower boundaries of the casing and hub end areas are obtained by the filtered discrete points, and the lower boundary surfaces of the casing and hub end areas, the transition surfaces of the upper and lower boundary curves, and the upper boundary surfaces of the end areas are constructed by using the upper and lower boundaries and the original casing and hub end walls. Finally, these surfaces are stitched to obtain a new variable geometry turbine casing and hub end area configuration. Compared with the variable geometry turbine in the original end area, this end area configuration technology significantly reduces the flow loss caused by the leakage flow of the end area gap, improves the efficiency of the guide vanes at all angles, and improves the aerodynamic performance of the variable geometry turbine.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] Step 1: Extract the discrete point data of the guide vane tip surface and the guide vane root tangent to the original end wall, and extract the discrete data points of the casing and hub end wall.

[0008] Step 2: Given a rotation axis and an angle range that needs to be rotated, the two sets of discrete point data obtained in step 1 are rotated around the rotation axis once every discrete angle within the rotation angle range to obtain a series of discrete point data of the end face of the casing and the end face of the hub after rotation;

[0009] Step 3: Fitting the casing and hub surfaces, filtering out the point set outside the original casing end area from the discrete point data of the rotated guide vane tip surface obtained in step 2, and filtering out the point set outside the original hub end area from the discrete point data of the rotated guide vane root;

[0010] Step 4: Project the point set outside the original casing end area onto the casing end wall, and project the points outside the original hub end area onto the hub end wall to obtain the lower boundaries of the casing and hub end areas;

[0011] Step 5: Select the outermost boundary point from the points outside the casing end area as the upper boundary of the new casing end area, and select the outermost boundary point from the points outside the hub end area as the upper boundary of the new hub end area;

[0012] Step 6: Construct new casing and hub end areas using the upper and lower boundary curves of the casing and hub end areas obtained in steps 4 and 5 and the original casing and hub end walls.

[0013] Furthermore, the step 1 is specifically as follows:

[0014] Step 1-1: Obtain the tangent surfaces between the original blade and the casing and hub in the modeling software as the tip and root end surfaces of the guide vane;

[0015] Step 1-2: Export the end face to MATLAB and use the stlread function to obtain the triangulation and discrete data points of the blade tip, blade root end face, casing, and hub end wall.

[0016] Furthermore, the step 2 is specifically as follows:

[0017] The coordinates of the point to be rotated are specified as P(x,y,z), and the normalized vector of the rotation axis is The starting point coordinates of the rotation axis are origin(origin x ,origin y ,origin z ), the rotation angle is alpha, and alph is the form conversion of alpha, from degree form to π form;

[0018] alph=alpha*pi / 180

[0019] sina=sin(alph)

[0020] cosa=cos(alph)

[0021] vera=1-cosa

[0022] Among them, a represents the abbreviation of alph, and pi represents π;

[0023] The rotation matrix is:

[0024]

[0025] P rot =(x rot ,y rot ,z rot )=(x-origin x ,y-origin y ,z-origin z )*T

[0026] Among them, P rot Indicates the rotated coordinates without considering the coordinates of the starting point;

[0027] The resulting rotated coordinates are:

[0028] P new =(x new ,y new ,z new )=(x rot +originx ,y rot +origin y ,z rot +origin z ).

[0029] Furthermore, the step 3 is specifically as follows:

[0030] Step 3-1: Obtain the point set after the blade tip surface is rotated by a series of discrete angles from step 2, and determine whether these points are outside the original casing end area. If they are inside the casing end area or on the casing end wall, discard them; if they are outside the casing end area, retain them;

[0031] Step 3-2: Obtain the point set after the blade root end face is rotated by a series of discrete angles in step 2, and determine whether these points are outside the original hub end area. If they are inside the hub end area or on the hub end wall, discard them; if they are outside the hub end area, retain them.

[0032] Furthermore, the step 4 is specifically as follows:

[0033] Step 4-1: Project the points outside the casing end area obtained in step 3 onto the casing end wall to form a new point set with the data points on the original blade tip surface, select the outer contour of the point set, and connect it into a closed curve as the lower boundary curve of the casing end area;

[0034] Step 4-2: Project the points outside the hub end area obtained in step 3 onto the hub end wall to form a new point set with the data points of the original blade root end face, select the outer contour of the point set, and connect it into a closed curve as the lower boundary curve of the hub end area.

[0035] Furthermore, the step 5 is specifically as follows:

[0036] Step 5-1: Take the points outside the end area of ​​the casing obtained in step 3 as a point set, and select the outer contour of the point set as the upper boundary curve of the end area of ​​the casing;

[0037] Step 5-2: Take the points outside the hub end area obtained in step 3 as a point set, and select the outer contour of the point set as the upper boundary curve of the hub end area.

[0038] Furthermore, the step 6 is specifically as follows:

[0039] Step 6-1: Create upper boundary surface from upper boundary curve: Use the fill surface and N-side surface functions of the modeling software to create the upper boundary surface between the upper boundary curves;

[0040] Step 6-2: Create transition surfaces between the upper and lower boundary curves from the upper and lower boundary curves: The upper and lower boundary curves are both irregular three-dimensional curves. The transition surfaces between the upper and lower boundaries of the casing and the hub are created respectively by means of sweeping, curve group and N-side surface;

[0041] Step 6-3: Create a lower boundary surface from the lower boundary curve and the original casing and hub end wall: the lower boundary curve at the casing is included in the original casing end wall, the casing part included in the lower boundary curve is deleted, and the casing end wall after deletion is used as the lower boundary surface of the casing; the lower boundary curve at the hub is included in the original hub end wall, the hub part included in the lower boundary curve is deleted, and the hub end wall after deletion is used as the lower boundary surface of the casing;

[0042] Step 6-4: Obtain new receiver and hub end area configurations: stitch the upper boundary surface, transition surface, and lower boundary surface of the receiver as a new receiver end area configuration, and stitch the upper boundary surface, transition surface, and lower boundary surface of the hub as a new hub end area configuration.

[0043] The beneficial effects of the present invention are as follows:

[0044] The present invention can ensure that the guide vane can rotate freely within a certain angle range by constructing a new casing and hub end area configuration in the casing and hub end area, and can change the flow capacity of the turbine by adjusting the guide vane throat area, which plays an important role in adjusting the flow, controlling the thrust, and adjusting the engine working point in the variable cycle engine. At the same time, this end area configuration can reduce the gap leakage flow loss caused by the end area gap leakage as much as possible, improve the efficiency of the variable geometry turbine, and improve the aerodynamic performance of the variable geometry turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the design process of the present invention;

[0046] Figure 2 It is a schematic diagram of discrete points of the guide vane tip and blade root end surface tangent to the original end wall of the present invention;

[0047] Figure 3 This is a schematic diagram of discrete points of the blade tip and blade root end surfaces obtained after rotation according to the present invention;

[0048] Figure 4 It is a schematic diagram of the end area of ​​the casing of the present invention;

[0049] Figure 5 It is a schematic diagram of the hub end area of ​​the present invention;

[0050] Figure 6 It is a general schematic diagram of the variable geometry turbine end area of ​​the present invention;

[0051] In the figure, 1. upper boundary curve of the receiver end area; 2. lower boundary curve of the receiver end area; 3. lower boundary surface of the receiver end area; 4. transition surface between the upper and lower boundaries of the receiver end area; 5. upper boundary surface of the receiver end area; 6. upper boundary curve of the hub end area; 7. lower boundary curve of the hub end area; 8. lower boundary surface of the hub end area; 9. transition surface between the upper and lower boundaries of the hub end area; 10. upper boundary surface of the hub end area. DETAILED DESCRIPTION

[0052] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0053] The purpose of the present invention is to solve the problem that when the end zone gap is too small, the wall guide vane contacts the casing and the end wall of the hub during rotation and gets stuck, and when the end zone gap is too large, the flow in the end zone gap causes flow loss. Based on the characteristics of the rotation of the variable geometry turbine guide vane, a variable geometry turbine end zone configuration method is proposed. This end zone configuration can wrap the guide vane in any rotation process, ensure that the guide vane does not contact the casing and the end wall of the hub during rotation, and reduce the loss caused by the end zone gap flow as much as possible.

[0054] To achieve the above object, the technical solution adopted by the present invention is:

[0055] The first step: extract the discrete point data of the guide vane tip surface tangent to the original end wall and the discrete point data of the guide vane root, and extract the discrete data points of the casing and hub end wall.

[0056] (1) In the modeling software, the tangent surfaces between the original blade and the casing and hub are obtained as the tip and root end surfaces of the guide vane.

[0057] (2) Export the end face to MATLAB and use the stlread function to obtain the triangulation and discrete data points of the blade tip, blade root end face, casing, and hub end wall.

[0058] Step 2: Given the rotation axis and the angle range that needs to be rotated, the discrete point data obtained in the first step is rotated around the rotation axis once every discrete angle within the rotation angle range to obtain a series of discrete point data of the casing end face and the hub end face after rotation.

[0059] The coordinates of the point to be rotated are specified as P(x,y,z), and the normalized vector of the rotation axis is The starting point coordinates of the rotation axis are origin(origin x ,origin y ,origin z ), the rotation angle is alpha, and alph is the form conversion of alpha, from degree form to π form.

[0060] alph=alpha*pi / 180

[0061] sina=sin(alph)

[0062] cosa=cos(alph)

[0063] vera=1-cosa

[0064] The rotation matrix is:

[0065]

[0066] P rot =(x rot ,y rot ,z rot )=(x-origin x ,y-origin y ,z-origin z )*T

[0067] The resulting rotated coordinates are:

[0068] P new =(x new ,y new ,z new )=(x rot +origin x ,y rot +origin y ,z rot +origin z )

[0069] Step 3: Fit the casing and hub surfaces, filter out the point set outside the original casing end area from the discrete point data of the rotated blade tip surface obtained in the second step, and filter out the point set outside the original hub end area from the discrete point data of the rotated blade root end surface.

[0070] (1) The second step obtains the point set after the blade tip surface is rotated by a series of discrete angles. It is determined whether these points are outside the original casing end area. If they are inside the casing end area or on the casing end wall, they are discarded. If they are outside the casing end area, they are retained.

[0071] (2) The point set obtained from the second step after the blade root end face is rotated by a series of discrete angles is judged whether these points are outside the original hub end area. If they are inside the hub end area or on the hub end wall, they are discarded; if they are outside the hub end area, they are retained.

[0072] Step 4: Project the point set outside the original casing end area onto the casing end wall, and project the points outside the original hub end area onto the hub end wall. Obtain the lower boundaries of the casing and hub end areas.

[0073] (1) Project the points outside the casing end area obtained in the third step onto the casing end wall to form a new point set with the data points on the original blade tip surface. Select the outer contour of the point set and connect it into a closed curve as the lower boundary curve of the casing end area.

[0074] (2) Project the points outside the hub end area obtained in the third step onto the hub end wall to form a new point set with the data points of the original blade root end face. Select the outer contour of the point set and connect it into a closed curve as the lower boundary curve of the hub end area.

[0075] Step 5: Select the outermost boundary point from the points outside the casing end area as the upper boundary of the new casing end area, and select the outermost boundary point from the points outside the hub end area as the upper boundary of the new hub end area.

[0076] (1) The points outside the end area of ​​the casing obtained in the third step are regarded as a point set, and the outer contour of the point set is selected as the upper boundary curve of the end area of ​​the casing.

[0077] (2) The points outside the hub end area obtained in the third step are taken as a point set, and the outer contour of the point set is selected as the upper boundary curve of the hub end area.

[0078] Step 6: Construct new casing and hub end areas based on the upper and lower boundary curves of the casing and hub end areas obtained in steps 4 and 5 and the original casing and hub end walls.

[0079] (1) Create an upper boundary surface from the upper boundary curve: Create an upper boundary surface between the upper boundary curves by using functions such as fill surface and N-side surface in the modeling software.

[0080] (2) Creating transition surfaces between the upper and lower boundary curves: The upper and lower boundary curves are both irregular three-dimensional curves, and the transition surfaces between the upper and lower boundaries of the casing and the hub can be created by sweeping, passing through curve groups and N-side surfaces.

[0081] (3) A lower boundary surface is created from the lower boundary curve and the original casing and wheel hub end wall: the lower boundary curve at the casing is included in the original casing end wall, the casing portion included in the lower boundary curve is deleted, and the deleted casing end wall is used as the lower boundary surface of the casing; the lower boundary curve at the wheel hub is included in the original wheel hub end wall, the wheel hub portion included in the lower boundary curve is deleted, and the deleted wheel hub end wall is used as the lower boundary surface of the casing.

[0082] (4) Obtaining new casing and hub end area configurations: stitching the casing upper boundary surface, transition surface, and casing lower boundary surface as a new casing end area configuration; stitching the wheel hub upper boundary surface, transition surface, and wheel hub lower boundary surface as a new wheel hub end area configuration.

[0083] Example:

[0084] like Figure 1 As shown: A variable geometry turbine end region configuration design method, comprising the following steps:

[0085] The first step: extract the discrete point data of the guide vane tip surface tangent to the original end wall and the discrete point data of the guide vane root, and extract the discrete data points of the casing and hub end wall.

[0086] Step 2: Given the rotation axis and the angle range that needs to be rotated, the discrete point data obtained in the first step is rotated around the rotation axis once every discrete angle within the rotation angle range to obtain a series of discrete point data of the casing end face and the hub end face after rotation.

[0087] Step 3: Filter out the point set outside the original casing end area from the discrete point data of the rotated blade tip surface obtained in the second step, and filter out the point set outside the original hub end area from the discrete point data of the rotated blade root end surface.

[0088] Step 4: Project the point set outside the original casing end area onto the casing end wall, and project the points outside the original hub end area onto the hub end wall. Obtain the lower boundaries of the casing and hub end areas.

[0089] Step 5: Select the outermost boundary point from the points outside the casing end area as the upper boundary of the new casing end area, and select the outermost boundary point from the points outside the hub end area as the upper boundary of the new hub end area.

[0090] Step 6: Construct new casing and hub end areas based on the upper and lower boundary curves of the casing and hub end areas obtained in steps 4 and 5 and the original casing and hub end walls.

[0091] (1) Create an upper boundary surface from the upper boundary curve;

[0092] (2) creating a transition surface between the upper and lower boundary curves from the upper and lower boundary curves;

[0093] (3) Create a lower boundary surface from the lower boundary curve and the original casing and hub end wall;

[0094] (4) The upper boundary surface, transition surface, and lower boundary surface are stitched together to form a new casing and hub end area configuration.

[0095] The first step is to obtain the discrete point data of the guide vane tip and blade root end surface tangent to the original end wall, which includes the following steps:

[0096] (1) In the modeling software, the tangent surfaces between the original blade and the casing and hub are obtained as the tip and root end surfaces of the guide vane.

[0097] (2) Export the end face to MATLAB and use the stlread function to obtain the triangulation and discrete data points of the blade tip, blade root end face, casing, and hub end wall.

[0098] The second step is to obtain the discrete point data of the rotated end face, which specifically includes the following steps:

[0099] The coordinates of the point to be rotated are specified as P(x,y,z), and the normalized vector of the rotation axis is The starting point coordinates of the rotation axis are: origin(origin x ,origin y ,origin z )=(134.15472,-3,0), the rotation angle range is alpha=15.

[0100] alph=alpha*pi / 180

[0101] sina=sin(alph)

[0102] cosa=cos(alph)

[0103] vera=1-cos(alph)

[0104] The rotation matrix is:

[0105]

[0106] P rot =(x rot ,y rot ,z rot )=(x-origin x ,y-origin y ,z-origin z )*T

[0107] The resulting rotated coordinates are:

[0108] P new =(x new ,y new ,z new )=(x rot +origin x ,y rot +origin y ,z rot +origin z )

[0109] The third step is to obtain points outside the casing and hub end area, which specifically includes the following steps:

[0110] (1) The discrete point shroud(x) passing through the end wall of the casing shroud ,y shroud ,z shroud ), after interpolation encryption, the casing surface is fitted. In this case, the z coordinate of the discrete point in the rotated point set and the z coordinate of the fitted casing surface under the same x coordinate and y coordinate are judged to determine whether it is outside the end area.

[0111] If x new =x shroud ,y new =y shroud , and the z coordinate of the rotated discrete point is greater than the z coordinate of the fitted casing surface z new >z shroud , keep these discrete points; if the z coordinate of the rotated discrete point is less than or equal to the z coordinate of the fitted casing surface z new <=z shroud , discard these discrete points.

[0112] (2) Through the discrete point hub(x hub ,y hub ,z hub ), after interpolation encryption, the hub surface is fitted. In this case, the z coordinate of the discrete point in the rotated point set and the z coordinate of the fitted hub surface under the same x coordinate and y coordinate are judged to determine whether it is outside the hub end area.

[0113] If x new =x hub ,y new =y hub , and the z coordinate of the rotated discrete point is less than the z coordinate of the fitted hub surface z new <z hub , keep these discrete points; if the z coordinate of the rotated discrete point is greater than or equal to the z coordinate of the fitted hub surface z new >=z hub , discard these discrete points.

[0114] The fourth step is to obtain the lower boundaries of the casing and the hub end area, which specifically includes the following steps:

[0115] (1) Project the points outside the casing end area obtained in the third step onto the casing end wall. Use the casing surface fitted in the third step to replace the z coordinates of the points outside the casing end surface screened in the third step with the z coordinates of the casing under the same x and y coordinates. After all the points are replaced, they form a new point set with the data points on the original blade tip surface. Select the outer contour of the point set and connect it into a closed curve as the lower boundary curve of the casing end area.

[0116] (2) Project the points outside the hub end area obtained in the third step onto the hub end wall. Using the hub surface fitted in the third step, replace the z coordinates of the points outside the hub end surface screened in the third step with the z coordinates of the casing under the same x and y coordinates. After all the points are replaced, they form a new point set with the data points of the original blade root end surface. Select the outer contour of the point set and connect it into a closed curve as the lower boundary curve of the hub end area.

[0117] The fifth step is to obtain the upper boundaries of the casing and the hub end area, which specifically includes the following steps:

[0118] (1) The points outside the end area of ​​the casing obtained in the third step are regarded as a point set, and the outer contour of the point set is selected as the upper boundary curve of the end area of ​​the casing.

[0119] (2) The points outside the hub end area obtained in the third step are taken as a point set, and the outer contour of the point set is selected as the upper boundary curve of the hub end area.

[0120] The sixth step is to obtain the variable geometry turbine casing and hub end area configuration, which specifically includes the following steps:

[0121] (1) Create an upper boundary surface from the upper boundary curve: Create an upper boundary surface between the upper boundary curves by using functions such as fill surface and N-side surface in the modeling software.

[0122] (2) Creating transition surfaces between the upper and lower boundary curves: The upper and lower boundary curves are both irregular three-dimensional curves, and the transition surfaces between the upper and lower boundaries of the casing and the hub can be created by sweeping, passing through curve groups and N-side surfaces.

[0123] (3) A lower boundary surface is created from the lower boundary curve and the original casing and wheel hub end wall: the lower boundary curve at the casing is included in the original casing end wall, the casing portion included in the lower boundary curve is deleted, and the deleted casing end wall is used as the lower boundary surface of the casing; the lower boundary curve at the wheel hub is included in the original wheel hub end wall, the wheel hub portion included in the lower boundary curve is deleted, and the deleted wheel hub end wall is used as the lower boundary surface of the casing.

[0124] (4) Obtaining new casing and hub end area configurations: stitching the casing upper boundary surface, transition surface, and casing lower boundary surface as a new casing end area configuration; stitching the wheel hub upper boundary surface, transition surface, and wheel hub lower boundary surface as a new wheel hub end area configuration.

Claims

1. A variable geometry turbine end region configuration method, characterized in that: The steps include: Step 1: Extract the discrete point data of the guide vane tip surface tangent to the original end wall and the discrete point data of the guide vane root, and extract the discrete data points of the casing and hub end wall; Step 2: Given a rotation axis and an angle range that needs to be rotated, the two sets of discrete point data obtained in step 1 are rotated around the rotation axis once every discrete angle within the rotation angle range to obtain a series of discrete point data of the end face of the casing and the end face of the hub after rotation; Step 3: Fitting the casing and hub surfaces, filtering out the point set outside the original casing end area from the discrete point data of the rotated guide vane tip surface obtained in step 2, and filtering out the point set outside the original hub end area from the discrete point data of the rotated guide vane root; Step 4: Project the point set outside the original casing end area onto the casing end wall, and project the points outside the original hub end area onto the hub end wall to obtain the lower boundaries of the casing and hub end areas; Step 5: Select the outermost boundary point from the points outside the casing end area as the upper boundary of the new casing end area, and select the outermost boundary point from the points outside the hub end area as the upper boundary of the new hub end area; Step 6: Construct new casing and hub end areas using the upper and lower boundary curves of the casing and hub end areas obtained in steps 4 and 5 and the original casing and hub end walls.

2. A variable geometry turbine end region configuration method according to claim 1, characterized in that: The step 1 is specifically as follows: Step 1-1: Obtain the tangent surfaces between the original blade and the casing and hub in the modeling software as the tip and root end surfaces of the guide vane; Step 1-2: Export the end face to MATLAB and use the stlread function to obtain the triangulation and discrete data points of the blade tip, blade root end face, casing, and hub end wall.

3. A variable geometry turbine end region configuration method according to claim 2, characterized in that: The step 2 is specifically as follows: The coordinates of the point to be rotated are specified as P(x,y,z), and the normalized vector of the rotation axis is The starting point of the rotation axis is origin(origin x ,origin y ,origin z ), the rotation angle is alpha, and alph is the form conversion of alpha, from degree form to π form; alph=alpha*pi / 180 sina=sin(alph) cosa=cos(alph) vera=1-cosa Among them, a represents the abbreviation of alph, and pi represents π; The rotation matrix is: P rot =(x rot ,y rot ,z rot )=(x-origin x ,y-origin y ,z-origin z )*T Among them, P rot Indicates the rotated coordinates without considering the coordinates of the starting point; The resulting rotated coordinates are: P new =(x new ,y new ,z new )=(x rot +origin x ,y rot +origin y ,z rot +origin z )。 4. A variable geometry turbine end region configuration method according to claim 3, characterized in that: The step 3 is specifically as follows: Step 3-1: Obtain the point set after the blade tip surface is rotated by a series of discrete angles from step 2, and determine whether these points are outside the original casing end area. If they are inside the casing end area or on the casing end wall, discard them; if they are outside the casing end area, retain them; Step 3-2: Obtain the point set after the blade root end face is rotated by a series of discrete angles in step 2, and determine whether these points are outside the original hub end area. If they are inside the hub end area or on the hub end wall, discard them; if they are outside the hub end area, retain them.

5. A variable geometry turbine end region configuration method according to claim 4, characterized in that: The step 4 is specifically as follows: Step 4-1: Project the points outside the casing end area obtained in step 3 onto the casing end wall to form a new point set with the data points on the original blade tip surface, select the outer contour of the point set, and connect it into a closed curve as the lower boundary curve of the casing end area; Step 4-2: Project the points outside the hub end area obtained in step 3 onto the hub end wall to form a new point set with the data points of the original blade root end face, select the outer contour of the point set, and connect it into a closed curve as the lower boundary curve of the hub end area.

6. A variable geometry turbine end region configuration method according to claim 5, characterized in that: The step 5 is specifically as follows: Step 5-1: Take the points outside the end area of ​​the casing obtained in step 3 as a point set, and select the outer contour of the point set as the upper boundary curve of the end area of ​​the casing; Step 5-2: Take the points outside the hub end area obtained in step 3 as a point set, and select the outer contour of the point set as the upper boundary curve of the hub end area.

7. A variable geometry turbine end region configuration method according to claim 6, characterized in that: The step 6 is specifically as follows: Step 6-1: Create upper boundary surface from upper boundary curve: Use the fill surface and N-side surface functions of the modeling software to create the upper boundary surface between the upper boundary curves; Step 6-2: Create transition surfaces between the upper and lower boundary curves from the upper and lower boundary curves: The upper and lower boundary curves are both irregular three-dimensional curves. The transition surfaces between the upper and lower boundaries of the casing and the hub are created respectively by means of sweeping, curve group and N-side surface; Step 6-3: Create a lower boundary surface from the lower boundary curve and the original casing and hub end wall: the lower boundary curve at the casing is included in the original casing end wall, the casing part included in the lower boundary curve is deleted, and the casing end wall after deletion is used as the lower boundary surface of the casing; the lower boundary curve at the hub is included in the original hub end wall, the hub part included in the lower boundary curve is deleted, and the hub end wall after deletion is used as the lower boundary surface of the casing; Step 6-4: Obtain new receiver and hub end area configurations: stitch the upper boundary surface, transition surface, and lower boundary surface of the receiver as a new receiver end area configuration, and stitch the upper boundary surface, transition surface, and lower boundary surface of the hub as a new hub end area configuration.

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