CN117150653A - Turbine modeling method and system for coupling non-axisymmetric end wall and leading edge modification - Google Patents
Turbine modeling method and system for coupling non-axisymmetric end wall and leading edge modification Download PDFInfo
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Abstract
The invention discloses a turbine modeling method and a system for coupling a non-axisymmetric end wall and leading edge modification, and relates to the field of aero-engine/gas turbine turbines, wherein the method comprises the following steps: constructing a circumferential control line on the lower end wall surface by adopting a sine function; constructing an axial control line on the lower end wall surface by adopting a unimodal function, and generating a non-axisymmetric end wall; respectively carrying out curve offset under three change rates on part of pressure surface contour lines and part of suction surface contour lines of the turbine blade, and determining a blade front edge trimming two-dimensional contour line; controlling the spanwise modeling of the two-dimensional contour line of the front edge modification of the blade by adopting the concave front edge stacking molded line to obtain the front edge modification of the blade; and coupling the non-axisymmetric end wall and the front edge of the blade to obtain a coupled non-axisymmetric end wall and front edge modification model of the blade, and completing the turbine modeling. The invention plays the advantages of non-axisymmetric end wall and blade front edge modification, weakens the dimension and strength of the front edge horseshoe vortex pressure surface branch, and improves the flow condition in the turbine runner.
Description
Technical Field
The invention relates to the technical field of aero-engine/gas turbine turbines, in particular to a turbine modeling method and a turbine modeling system for coupling a non-axisymmetric end wall and leading edge modification.
Background
Lifting thrust to weight ratio is a major trend in modern high bypass ratio turbofan engine designs, where low pressure turbine components may account for 30% of the total mass of the engine. Related studies have shown that weight loss of low pressure turbine components is critical to elevating thrust-to-weight ratio. Reducing the number of turbine stages and reducing the number of blades of a single stage turbine is two major ways to reduce low pressure turbine components, and high load design of low pressure turbine blades is an important means to achieve both. However, the transverse pressure gradients within the ultra-high load turbine blade channels are more exacerbated relative to conventional load blades, resulting in more complex development of endregion secondary flow within the channels, including leading edge horseshoe vortices, channel vortices, and the like, resulting in greater endregion flow losses. Therefore, it is important to develop end region flow regulation means suitable for ultra-high load blades to break through the performance bottleneck thereof.
Disclosure of Invention
The invention aims to provide a turbine modeling method and a turbine modeling system for coupling a non-axisymmetric end wall and a front edge modification, which are used for weakening the dimension and the strength of a front edge horseshoe vortex pressure surface branch and improving the flow condition in a turbine runner.
In order to achieve the above object, the present invention provides the following solutions:
a method of turbine modeling coupling a non-axisymmetric endwall and leading edge modification, said turbine comprising a turbine lower endwall surface and a plurality of turbine blades circumferentially and uniformly disposed on said lower endwall surface, the space between two adjacent turbine blades being a blade channel; one side of the turbine blade is a pressure surface, the other side of the turbine blade is a suction surface, and the turbine modeling method comprises the following steps:
constructing a circumferential control line on the lower end wall surface by adopting a sine function;
constructing an axial control line on the lower end wall surface by adopting a unimodal function;
generating a B spline curve based on the axial positions of control points formed by the circumferential control line and the axial control line;
connecting the B spline curve with the axial control line along the circumferential direction to generate a non-axisymmetric end wall;
respectively carrying out curve offset under three change rates on part of pressure surface contour lines and part of suction surface contour lines of the turbine blade;
determining a blade front edge trimming two-dimensional contour line based on the partial pressure surface contour line and the partial suction surface contour line which are newly generated after the offset;
controlling the spanwise modeling of the two-dimensional contour line of the front edge modification of the blade by adopting a concave front edge stacking molded line to obtain the front edge modification of the blade;
and coupling the non-axisymmetric end wall and the blade front edge modification to obtain a coupled non-axisymmetric end wall and blade front edge modification model, and completing turbine modeling.
Optionally, the number of the circumferential control lines is 9, and the number of the axial control lines is 5; the 9 circumferential control lines are uniformly distributed at the axial positions of different lower end wall surfaces from the leading edge to the trailing edge of the blade channel, and the 5 axial control lines are uniformly distributed at the circumferential positions of different lower end wall surfaces from one camber line to the other camber line.
Optionally, the expression of the circumferential control function C (y) of the sinusoidal function is as follows:
wherein A (x) is an axial amplitude function, x is the coordinate position of an axial control point, y is the coordinate position of a circumferential control point, and t is the distance between the camber lines of two adjacent turbine blades.
Optionally, the expression of the axial amplitude function is as follows:
wherein M is an amplitude control coefficient and takes on valueIn the range of 2mm-10mm, C x Is the axial chord length of the blade.
Optionally, determining the blade leading edge modified two-dimensional contour line based on the partial pressure surface contour line and the partial suction surface contour line which are newly generated after the offset specifically comprises:
connecting the part of the pressure surface contour lines newly generated after the biasing with the other part of the original pressure surface contour lines; and connecting the newly generated part of the suction surface contour line after the offset with the other part of the original suction surface contour line to finish the design of the blade front edge repair type two-dimensional contour line.
Optionally, a control equation of the concave leading edge stacking line is as follows:
l＝h n (n＝log H L UP ，n≥1)
wherein L is the axial length of a certain control point on the front edge laminated line extending forwards, H is the radial height of a certain control point on the front edge laminated line, H is the radial height of the front edge trimming geometry, and L UP The axial distance from the original airfoil leading edge point for the leading edge modification geometry leading edge point.
Optionally, the axial distance L of the leading edge modification geometric leading edge point from the original blade profile leading edge point UP Greater than or equal to the radial height H of the leading edge profile geometry.
The present invention also provides a turbine modeling system for coupling a non-axisymmetric end wall and a leading edge modification, comprising:
a circumferential control line construction module for constructing a circumferential control line on the lower end wall surface using a sinusoidal function;
an axial control line construction module for constructing an axial control line on the lower end wall surface using a unimodal function;
the B spline curve generation module is used for generating a B spline curve based on the axial positions of all control points formed by the circumferential control line and the axial control line;
the non-axisymmetric end wall generating module is used for connecting the B-spline curve with the axial control line along the circumferential direction to generate a non-axisymmetric end wall;
the offset module is used for respectively carrying out curve offset under three change rates on part of pressure surface contour lines and part of suction surface contour lines of the turbine blade;
the blade front edge modification two-dimensional contour line determining module is used for determining a blade front edge modification two-dimensional contour line based on the partial pressure surface contour line and the partial suction surface contour line which are newly generated after the offset;
the blade front edge modification determining module is used for controlling the spreading and shaping of the two-dimensional profile line of the blade front edge modification by adopting the concave front edge stacking line to obtain the blade front edge modification;
and the coupling module is used for coupling the non-axisymmetric end wall and the blade front edge modification to obtain a coupled non-axisymmetric end wall and blade front edge modification model, and completing turbine modeling.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention firstly uses sine function and single peak function to accurately control the circumferential direction and the axial direction of the non-axisymmetric end wall, then designs the front edge contour line of the blade through offset curve and applies control function to the front edge stacking line to generate the front edge modification of the blade, and finally, the non-axisymmetric end wall and the front edge modification of the blade are coupled to form the non-axisymmetric end wall and the front edge modification coupling model of the blade. The method fully exerts the advantages of the non-axisymmetric end wall design method and the blade leading edge modification method. Compared with an independent front edge modification design, the coupling model further weakens the dimensions of the transverse pressure gradient and the channel vortex in the channel; compared with an independent non-axisymmetric end wall design, the coupling model further weakens the dimension and strength of the leading edge horseshoe vortex pressure surface branch, and improves the flow condition in the turbine runner.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method of turbine modeling coupling a non-axisymmetric end wall and leading edge modification provided in accordance with a first embodiment of the present invention;
FIG. 2 is a schematic illustration of a non-axisymmetric endwall control point distribution of a turbine modeling method coupling a non-axisymmetric endwall and a blade leading edge modification;
FIG. 3 is a schematic diagram of a circumferential control law of a sinusoidal function of a non-axisymmetric end wall;
FIG. 4 is a schematic diagram of the B-spline axial control law of a non-axisymmetric end wall;
FIG. 5 is a schematic view of the radial height variation of a non-axisymmetric end wall;
FIG. 6 is a schematic view of a pressure side and suction side profile of a blade leading edge modification method;
FIG. 7 is a schematic view of a leading edge stacking line of a blade leading edge modification method;
FIG. 8 is a schematic view of an impeller after a turbine molding process coupling a non-axisymmetric endwall and a blade leading edge modification.
FIG. 9 is a schematic illustration of the total pressure loss radial distribution after a turbine modeling method employing coupling of non-axisymmetric endwalls and blade leading edge modifications.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Numerous scholars have developed extensive research into the flow control effect of non-axisymmetric end walls at the turbine end region. Since Rose et al first designed non-axisymmetric end walls in the seventies of the last century, more types of non-axisymmetric end wall design methods were validated in numerical simulations or experiments. In recent years, the use of the non-axisymmetric end wall technique in high pressure turbine poles by rogers Luo Yisi has resulted in a 0.4% improvement in turbine stage efficiency. At the same time, leading edge modification techniques that create a chamfer-like structure at the blade and endwall junction have proven effective for weakening the leading edge horseshoe vortex dimensions. Conventionally, the front edge trimming structure can be divided into a strip-shaped front edge structure and a spherical front edge structure according to different front edge stacking molded lines, and numerical simulation or experimental research results of Mahmood, zess and other scholars show that the two structures can effectively comb the flow of low-energy fluid in the channel, and the secondary flow loss of the end region is reduced. Non-axisymmetric endwall and blade leading edge modification techniques are widely appreciated by designers due to their manufacturability and effectiveness of the control means. The invention provides a turbine modeling method for coupling a non-axisymmetric end wall and blade front edge modification, which aims to fully mine the coupling flow control potential of the non-axisymmetric end wall and the blade front edge modification, and weaken the secondary flow loss of a turbine end region to a greater extent.
The invention aims to provide a turbine modeling method and a turbine modeling system for coupling a non-axisymmetric end wall and a front edge modification, which fully play the advantages of the non-axisymmetric end wall design method and the blade front edge modification method.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Example 1
The turbine comprises a lower end wall surface of the turbine and a plurality of turbine blades uniformly arranged on the lower end wall surface along the circumferential direction, and a space between two adjacent turbine blades is a blade channel; one side of the turbine blade is a Pressure Surface (PS), and the other side of the turbine blade is a Suction Surface (SS). As shown in fig. 1, the turbine modeling method for coupling the non-axisymmetric end wall and the leading edge modification provided in this embodiment includes the following steps:
s1: a circumferential control line is constructed on the lower end wall surface using a sinusoidal function.
As shown in fig. 3, the circumferential control line is constructed by adopting a sine function, in one blade channel, the sine function of one complete period starts from a blade camber line and ends at an adjacent blade camber line, so that the peak value of the function forms a convex end wall close to the pressure surface side of the blade to accelerate the fluid in the area, the local pressure is reduced, the valley value of the function forms a concave end wall close to the suction surface side of the blade to decelerate the fluid in the area, and the local pressure is increased. The circumferential control function C (y) of the sinusoidal function is defined as follows:
wherein A (x) is an axial amplitude function, y is the coordinate position of a circumferential control point, and t is the distance between the camber lines of two adjacent turbine blades.
S2: an axial control line is constructed on the lower end wall surface using a unimodal function.
As shown in fig. 4, the axial control line is constructed using a unimodal function, wherein the near pressure face side (control line 2) is defined as follows:
wherein M is an amplitude control coefficient, the value range is 2mm-10mm, C x For the axial chord length of the blade, x is the coordinate position of the axial control point, and the radial height value of the control point on the side (4 th control line) near the suction surface is the opposite number.
As shown in fig. 2, 9 circumferential control lines (solid lines) and 5 axial control lines (broken lines) are uniformly distributed on the original flat lower end wall, and 45 control points formed by the control lines can realize fine control on the geometry of the lower end wall. The radial heights of 27 control points (hollow points) on the 1 st, 3 rd and 5 th axial control lines are all 0, and 18 control points (solid points) on the 2 nd and 4 th axial control lines are variable control points.
S3: a B-spline curve is generated based on the axial position of each control point formed by the circumferential control line and the axial control line.
S4: and connecting the B spline curve with the axial control line along the circumferential direction to generate a non-axisymmetric end wall.
The B-spline curves connect the axial control lines smoothly in the circumferential direction to create non-axisymmetric end walls of the non-axisymmetric end walls, as shown in fig. 5.
S5: and (3) respectively carrying out curve offset under three change rates on part of the pressure surface contour line and part of the suction surface contour line of the turbine blade.
As shown in fig. 6, the curve offset at the rate of three changes is performed on a part of the pressure surface contour line (the axial distance LPS of the original blade profile leading edge point from the pressure surface modification end point) and a part of the suction surface contour line (the axial distance LSS of the original blade profile leading edge point from the suction surface modification end point) of the original blade, the initial value of the offset is 0, and the final value is the pre-designed leading edge modification geometric thickness LUP.
And the curve offset under the three change rates is respectively carried out on the partial pressure surface profile and the partial suction surface profile of the original blade, so that the second-order continuity of the newly generated partial pressure surface profile curve and the other partial original pressure surface profile curve is ensured, and the second-order continuity of the newly generated partial suction surface profile curve and the other partial original suction surface profile curve is ensured.
S6: and determining the blade front edge modified two-dimensional contour line based on the partial pressure surface contour line and the partial suction surface contour line which are newly generated after the offset.
And connecting the part of the pressure surface contour line newly generated after the offset with the other part of the original pressure surface contour line, and connecting the part of the suction surface contour line newly generated after the offset with the other part of the original suction surface contour line to complete the design of the blade leading edge repair type two-dimensional contour line.
S7: and controlling the spanwise modeling of the two-dimensional contour line of the blade front edge modification by adopting the concave front edge stacking molded line to obtain the blade front edge modification.
As shown in fig. 7, the concave leading edge lamination line is used to control the spanwise modeling of the leading edge trim geometry, and the control equation is as follows:
l＝h n (n＝log H L UP ，n≥1)
where L is the axial length of the forward extension of a control point on the leading edge lamination line, H is the radial height of a control point on the leading edge lamination line, H is the radial height of the leading edge repair geometry, L UP Is the axial distance of the leading edge modified geometry leading edge point from the original airfoil leading edge point. By being at different radial positionsThe leading edge profile geometry is generated from the two-dimensional set of contour curves.
Axial distance L of leading edge modification geometric leading edge point from original blade profile leading edge point UP The control equation of the concave front edge stacking line can ensure that the front edge geometry and the lower end wall plane have first-order continuity.
S8: and coupling the non-axisymmetric end wall and the front edge of the blade to obtain a coupled non-axisymmetric end wall and front edge modification model of the blade, and completing the turbine modeling.
As shown in fig. 8, the shaped non-axisymmetric end wall and the blade front edge modification geometry are coupled to construct a coupled non-axisymmetric end wall and blade front edge modification model, and the coupled model enables the non-axisymmetric lower end wall and the blade front edge geometry to intersect at the end wall and ensures smooth transition of the junction geometry, so that fine regulation and control of the turbine blade channel geometry are realized.
Example two
In order to better understand the method provided in the first embodiment, this embodiment is described with a specific example.
According to the operation process for realizing the coupling of the non-axisymmetric end wall and the modification of the front edge of the blade, a certain high-load low-pressure turbine blade grid is selected for flow control, and the flow regulation and control effect of the high-load low-pressure turbine blade grid on the secondary flow of the end region is searched through numerical simulation.
According to the operation steps, the non-axisymmetric end wall and the blade front edge modification coupling design is realized, the amplitude control coefficient M of the non-axisymmetric end wall is set to be 5.85mm, and the axial distance L between the original blade front edge point and the pressure surface modification end point is set to be 5.85mm PS Set to 68.25mm, leading edge modified geometric thickness L UP Set to be 12.77mm of the axial distance L from the original blade profile leading edge point to the suction surface modification end point sS Set to 13.50mm and the radial height H of the leading edge repair geometry set to 16.16mm. Before and after turbine cascade expansion numerical calculation is applied to the turbine modeling method under the condition of inlet chord Reynolds number Re=200000, and flow control objects are a prototype low-pressure turbine cascade runner, a cascade runner after non-axisymmetric end wall modeling, a cascade runner after front edge modeling and a cascade after coupling design modeling respectivelyA flow channel. The effectiveness of the turbine modeling method is judged by the magnitude of the total pressure loss coefficient behind the grid, and the total pressure loss coefficient lambda and the relative reduction of the total pressure loss coefficient delta lambda are defined as follows:
wherein P is o,i Represents the average total pressure of the mass flow of the inlet of the flow field, P o,loc Represents the average total pressure of the mass flow, P o,plane1 Represents P lane1 Average total pressure of section mass flow, P s,plane1 Represents P lane1 Average static pressure of section mass flow. P (P) lane1 The axial distance of the section from the trailing edge of the blade cascade is 40% of the axial chord length of the blade. Lambda (lambda) Ref Lambda is the total pressure loss coefficient of the original turbine blade cascade Opt Is the total pressure loss coefficient after various flow control methods are adopted. As shown in Table 1, the non-axisymmetric endwall model and the blade leading edge modification model reduced the total pressure loss factor by 5.57% and 8.78%, while the coupled flow control model reduced the total pressure loss factor by 15.07% and achieved excellent coupled flow control.
TABLE 1 comparison of end bend coupling control effects
Fig. 9 shows the radial distribution of the total pressure loss coefficient of four control objects on section 1. After the front edge is shaped, the total pressure loss coefficient in the area below 0.1 times of radial height is increased, and the total pressure loss coefficient in the area from 0.1 times of radial height to 0.2 times of radial height is obviously reduced. After the non-axisymmetric end wall is molded, the total pressure loss coefficient in the area below 0.1 times of radial height is basically unchanged, and the total pressure loss coefficient in the range from 0.1 times of radial height to 0.2 times of radial height is obviously reduced. The coupling model effectively plays the advantages of the two, and further expands the flow regulation and control effect on the area in the near leaf. Compared with an independent front edge modification design, the coupling model further weakens the dimensions of the transverse pressure gradient and the channel vortex in the channel; compared with an independent non-axisymmetric end wall design, the coupling model further weakens the dimension and strength of the leading edge horseshoe vortex pressure surface branch, and improves the flow condition in the turbine runner.
Example III
In order to perform a corresponding method of the above-described embodiments to achieve the corresponding functions and technical effects, a turbine modeling system that couples a non-axisymmetric end wall and a leading edge modification is provided below.
The system comprises:
the circumferential control line construction module is used for constructing a circumferential control line on the lower end wall surface by adopting a sine function;
an axial control line construction module for constructing an axial control line on the lower end wall surface by adopting a unimodal function;
the B spline curve generation module is used for generating a B spline curve based on the axial positions of the control points formed by the circumferential control line and the axial control line;
the non-axisymmetric end wall generating module is used for generating a non-axisymmetric end wall by connecting the B spline curve with an axial control line along the circumferential direction;
the offset module is used for respectively carrying out curve offset under three change rates on part of pressure surface contour lines and part of suction surface contour lines of the turbine blade;
the blade front edge modification two-dimensional contour line determining module is used for determining a blade front edge modification two-dimensional contour line based on the partial pressure surface contour line and the partial suction surface contour line which are newly generated after the offset;
the blade front edge trimming determining module is used for controlling the spanwise modeling of the two-dimensional profile line of the blade front edge trimming by adopting the concave front edge stacking profile to obtain the blade front edge trimming;
and the coupling module is used for coupling the non-axisymmetric end wall and the blade front edge modification to obtain a coupled non-axisymmetric end wall and blade front edge modification model, and completing turbine modeling.
The turbine modeling method and system for coupling the non-axisymmetric end wall and the front edge modification fully play the advantages of the non-axisymmetric end wall design method and the blade front edge modification method, weaken the dimension and strength of the front edge horseshoe vortex pressure surface branch, and improve the flow condition in the turbine runner.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (8)
1. A method of turbine modeling coupling a non-axisymmetric endwall and leading edge modification, said turbine comprising a turbine lower endwall surface and a plurality of turbine blades circumferentially and uniformly disposed on said lower endwall surface, the space between two adjacent turbine blades being a blade channel; one side of the turbine blade is a pressure surface, and the other side of the turbine blade is a suction surface, and the turbine modeling method is characterized by comprising the following steps:
constructing a circumferential control line on the lower end wall surface by adopting a sine function;
constructing an axial control line on the lower end wall surface by adopting a unimodal function;
generating a B spline curve based on the axial positions of control points formed by the circumferential control line and the axial control line;
connecting the B spline curve with the axial control line along the circumferential direction to generate a non-axisymmetric end wall;
respectively carrying out curve offset under three change rates on part of pressure surface contour lines and part of suction surface contour lines of the turbine blade;
determining a blade front edge trimming two-dimensional contour line based on the partial pressure surface contour line and the partial suction surface contour line which are newly generated after the offset;
controlling the spanwise modeling of the two-dimensional contour line of the front edge modification of the blade by adopting a concave front edge stacking molded line to obtain the front edge modification of the blade;
and coupling the non-axisymmetric end wall and the blade front edge modification to obtain a coupled non-axisymmetric end wall and blade front edge modification model, and completing turbine modeling.
2. The turbine molding method of coupling a non-axisymmetric end wall and a leading edge modification of claim 1, wherein the number of circumferential control lines is 9 and the number of axial control lines is 5; the 9 circumferential control lines are uniformly distributed at the axial positions of different lower end wall surfaces from the leading edge to the trailing edge of the blade channel, and the 5 axial control lines are uniformly distributed at the circumferential positions of different lower end wall surfaces from one camber line to the other camber line.
3. The turbine modeling method of coupling a non-axisymmetric endwall and a leading edge modification of claim 1, wherein the expression of the circumferential control function C (y) of the sinusoidal function is as follows:
wherein A (x) is an axial amplitude function, x is the coordinate position of an axial control point, y is the coordinate position of a circumferential control point, and t is the distance between the camber lines of two adjacent turbine blades.
4. A method of turbine modeling coupling a non-axisymmetric endwall and a leading edge modification according to claim 3, wherein said axial magnitude function is expressed as follows:
wherein M is an amplitude control coefficient, the value range is 2mm-10mm, C x Is the axial chord length of the blade.
5. The method of turbine modeling coupling a non-axisymmetric endwall and a leading edge modification of claim 1, wherein determining a blade leading edge modification two-dimensional profile based on the offset newly generated partial pressure side profile and the partial suction side profile, specifically comprises:
connecting the part of the pressure surface contour lines newly generated after the biasing with the other part of the original pressure surface contour lines; and connecting the newly generated part of the suction surface contour line after the offset with the other part of the original suction surface contour line to finish the design of the blade front edge repair type two-dimensional contour line.
6. The turbine molding method of coupling a non-axisymmetric endwall and a leading edge modification of claim 1, wherein the control equation for the concave leading edge stacking line is as follows:
l＝h n (n＝log H L UP ，n≥1)
wherein L is the axial length of a certain control point on the front edge laminated line extending forwards, H is the radial height of a certain control point on the front edge laminated line, H is the radial height of the front edge trimming geometry, and L UP The axial distance from the original airfoil leading edge point for the leading edge modification geometry leading edge point.
7. The turbine modeling method of coupling a non-axisymmetric endwall and a leading edge modification of claim 6, wherein the leading edge modification geometric leading edge point is an axial distance L from the original airfoil leading edge point UP Greater than or equal to the radial height H of the leading edge profile geometry.
8. A turbine modeling system for coupling a non-axisymmetric end wall and a leading edge modification, comprising:
a circumferential control line construction module for constructing a circumferential control line on the lower end wall surface using a sinusoidal function;
an axial control line construction module for constructing an axial control line on the lower end wall surface using a unimodal function;
the B spline curve generation module is used for generating a B spline curve based on the axial positions of all control points formed by the circumferential control line and the axial control line;
the non-axisymmetric end wall generating module is used for connecting the B-spline curve with the axial control line along the circumferential direction to generate a non-axisymmetric end wall;
the offset module is used for respectively carrying out curve offset under three change rates on part of pressure surface contour lines and part of suction surface contour lines of the turbine blade;
the blade front edge modification two-dimensional contour line determining module is used for determining a blade front edge modification two-dimensional contour line based on the partial pressure surface contour line and the partial suction surface contour line which are newly generated after the offset;
the blade front edge modification determining module is used for controlling the spreading and shaping of the two-dimensional profile line of the blade front edge modification by adopting the concave front edge stacking line to obtain the blade front edge modification;
and the coupling module is used for coupling the non-axisymmetric end wall and the blade front edge modification to obtain a coupled non-axisymmetric end wall and blade front edge modification model, and completing turbine modeling.
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