Method for designing blade profile of turbine support plate with continuous curvature

Abstract

The invention provides a method for designing a blade profile of a turbine support plate with continuous curvature. The method comprises the following steps of: S1, calculating the size and the position of a leading edge ellipse; s2, calculating a tangent point of a chord line and a leading edge ellipse; calculating a tangent point of the leading edge ellipse and the frontal line; calculating tangent point coordinates of the pressure side molded line and the suction side molded line with the front edge; s3, calculating a trailing edge circle center coordinate; s4, calculating tangent point coordinates of the pressure side molded line and the suction side molded line with the trailing edge; s5, acquiring a pressure side molded line and a suction side molded line according to the curvature constraint and the control point coordinates; s6, obtaining a blade profile; geometric parameters input by the design method comprise a leading edge diameter, a leading edge ovality, a trailing edge diameter, a mounting angle, an inlet structure angle, a geometric outlet angle, a leading edge pressure side wedge angle, a leading edge suction side wedge angle, a trailing edge wedge angle and an axial chord length. The curvature of the connecting position of the front edges of the supporting plate blades can be continuous, and the aerodynamic performance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine, in particular to a turbine strut vane profile design method with continuous curvature. BACKGROUND

[0002] Aero-engine turbine blade is obtained by stacking blade profiles along the radial direction, and the flow performance of the blade profile directly affects the aerodynamic performance of the turbine. The 11-parameter method is the most widely used parameterized design method for blade profiles in the field of turbine design. The input geometric parameters of the method are: inlet configuration angle, installation angle, outlet effective angle, rear bend angle, outlet angle coefficient, blade profile cross-section radius, chord length, leading edge wedge angle, trailing edge wedge angle, leading edge diameter, and trailing edge diameter.

[0003] The 11-parameter method restricts the throat of the blade, which causes certain difficulties in the design of inter-stage casing strut vanes and rear casing strut vanes. In addition, the conventional 11-parameter method has discontinuous curvature at the leading edge, which causes abnormal fluctuations in the Mach number near the discontinuous point and increases the profile loss.

[0004] Therefore, the present application provides a turbine strut vane profile design method with continuous curvature to overcome the above technical problems. SUMMARY

[0005] The present application provides a turbine strut vane profile design method with continuous curvature to overcome the above technical problems.

[0006] The present application solves the above technical problems by the following technical scheme:

[0007] The present application provides a turbine strut vane profile design method with continuous curvature, which comprises the following steps: S1, calculating the size and position of the leading edge ellipse; S2, calculating the tangent point of the chord line and the leading edge ellipse, the tangent point of the leading edge ellipse and the camber line, and the tangent point coordinates of the pressure side profile line and the suction side profile line and the leading edge; S3, calculating the tail edge center coordinates; S4, calculating the tangent point coordinates of the pressure side profile line and the suction side profile line and the tail edge; S5, obtaining the pressure side profile line and the suction side profile line according to the curvature constraint and the control point coordinates; S6, obtaining the blade profile. The input geometric parameters of the design method include: leading edge diameter, leading edge ellipticity, trailing edge diameter, installation angle, inlet configuration angle, geometric outlet angle, leading edge pressure side wedge angle, leading edge suction side wedge angle, trailing edge wedge angle, and axial chord length.

[0008] According to one or more embodiments of the present application, the calculation process of step S1 comprises: S11 , inputting a leading edge diameter, a leading edge ellipticity and an inlet configuration angle; S 12 , calculating an expression of a leading edge ellipse according to the leading edge diameter, the leading edge ellipticity and the inlet configuration angle, determining a size and a position of the leading edge ellipse.

[0009] According to one or more embodiments of the present application, the calculation process of the step S2 comprises: S 21 , inputting an installation angle, an inlet configuration angle, a leading edge pressure side wedge angle and a leading edge suction side wedge angle; S 22 , obtaining a direction of a chord line according to the installation angle, calculating two tangent points of the chord line and the leading edge ellipse according to a tangent relationship between a straight line and an ellipse, taking a tangent point with a smaller y coordinate value as a first tangent point according to a physical position relationship between a leading edge and a trailing edge of a blade profile, the first tangent point being a tangent point of the chord line and the leading edge ellipse, calculating two tangent points of the leading edge ellipse and a camber line according to the tangent relationship between the straight line and the ellipse based on the camber line being parallel to the y axis, taking a tangent point with a smaller x coordinate value as a second tangent point according to the physical position relationship between the leading edge and the trailing edge of the blade profile, the second tangent point being a tangent point of the camber line and the leading edge ellipse, obtaining a direction of a second straight line according to the inlet configuration angle, the second straight line being tangent to the leading edge ellipse and forming a third tangent point in a counterclockwise direction of a long axis of the leading edge ellipse by the leading edge pressure side wedge angle, and obtaining a direction of a third straight line according to the inlet configuration angle, the third straight line being tangent to the leading edge ellipse and forming a fourth tangent point in a clockwise direction of the long axis of the leading edge ellipse by the leading edge suction side wedge angle, the third tangent point being a tangent point of a pressure side profile line and the leading edge ellipse, the fourth tangent point being a tangent point of a suction side profile line and the leading edge ellipse, and determining coordinates of the third tangent point and the fourth tangent point, calculating curvatures of the third tangent point on the leading edge ellipse and the fourth tangent point on the leading edge ellipse according to an expression of the leading edge ellipse.

[0010] According to one or more embodiments of the present application, the calculation process of the step S3 comprises: S 31 , inputting an axial chord length and a trailing edge diameter; S 32 , obtaining a tangent point of a first straight line of a trailing edge and a camber line direction as a fifth tangent point according to the axial chord length and the second tangent point, determining an X coordinate of the fifth tangent point, the X coordinate of the fifth tangent point being the same as an X coordinate of a center of the trailing edge circle, obtaining a straight line expression of the chord line according to the chord line and the first tangent point, and obtaining two circles according to the trailing edge diameter and a tangent constraint of a circle and a straight line, taking a circle with a larger Y coordinate of a center as a small trailing edge circle according to a physical relationship between a leading edge and a trailing edge of a blade profile, and taking a center coordinate of the small trailing edge circle as a center coordinate of the trailing edge circle.

[0011] According to one or more embodiments of the present application, the calculation process of the step S4 comprises: S 41 , inputting a geometric outlet angle and a trailing edge wedge angle; S 42Based on the geometric exit angle and the coordinates of the trailing edge center, the direction of the exit geometric line is obtained; a third straight line, clockwise at 1 / 2 the trailing edge wedge angle, is tangent to the trailing edge small circle, forming the sixth tangent point; a fourth straight line, counterclockwise at 1 / 2 the trailing edge wedge angle, is tangent to the trailing edge small circle, forming the seventh tangent point; the coordinates of the sixth and seventh tangent points are determined; the sixth tangent point is the tangent point between the pressure side profile and the trailing edge, and the seventh tangent point is the tangent point between the suction side profile and the trailing edge.

[0012] According to one or more embodiments of the present invention, in step S5, the pressure-side profile is formed using an n-order Bézier curve (n≥3, and n is an integer), and the pressure-side profile includes n+1 first control points, namely point P. p1 Point P p2 ... point P pn and point P p(n+1) The leading edge profile and the pressure side profile meet at point P. p1 The trailing edge profile and the pressure side profile are tangent at point P. p(n+1) Tangent at point P; the curvature constraint method is based on point P. p1 The curvature k at the leading edge p1 The curvature formula of the Bézier curve is used to obtain point P. p2 The coordinates of point P; p1 The curvature k on the pressure side profile p1 The curvature of a Bézier curve satisfies the following formula: Among them, point P p2 Among the n+1 first control points, point P p1 Adjacent points, and point P p2 At point P p1 Move along the tangent line; point P p3 Among the n+1 first control points, point P p2 Adjacent points, and point P p3 At point P p(n+1) Move along the tangent or point P p3 Move in any direction; h p Let P be the point p3 Distance from point P p1 and point P p2 The perpendicular distance from the line in which it lies; a p Let P be the point p1 and point P p2 The distance between the line segments; based on point P p3 Location and point P p1 The tangent direction is used to calculate h. p ; The curvature of the Bézier curve is calculated using the above formula. p The value of a, according to a p The value of point P is calculated.p2 The coordinate values.

[0013] According to one or more embodiments of the present invention, when n=3, P p3 At point P p4 The point moves along the tangent direction. During the movement, point P... p2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the pressure side profile.

[0014] According to one or more embodiments of the present invention, when n=4, point P p3 P can move freely in any direction. p4 At point P p5 The point moves along the tangent direction. During the movement, point P... p2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the pressure side profile.

[0015] According to one or more embodiments of the present invention, in step S5, the suction side profile is formed using an n-order Bézier curve (n≥3, and n is an integer), and the suction side profile includes n+1 second control points, namely point P. s1 Point P s2 ... point P sn and point P s(n+1) The trailing edge profile and the suction side profile meet at point P. s(n+1) Tangent at point P; the curvature constraint method is based on point P. s1 The curvature k at the leading edge s1 The curvature formula of the Bézier curve is used to obtain point P. s2 The coordinates of point P; s1 The curvature k on the suction side profile s1 The curvature of a Bézier curve satisfies the following formula: Among them, point P s2 Among the n+1 second control points, point P s1 Adjacent points, and point P s2 At point P s1 Move along the tangent line; point P s3 Among the n+1 second control points, point P s2 Adjacent points, and point P s3 At point P p(n+1) Move along the tangent or point P s3 Move in any direction; h s Let P be the point s3 Distance from point P s1 and point P s2 The perpendicular distance from the line in which it lies; a s Let P be the point s1 and point P s2 The distance between the line segments; based on point Ps3 Location and point P s1 The tangent direction is used to calculate h. s ; The curvature of the Bézier curve is calculated using the above formula. s The value of a, according to a s The value of point P is calculated. s2 The coordinate values.

[0016] According to one or more embodiments of the present invention, when n=3, P s3 At point P s4 The point moves along the tangent direction. During the movement, point P... s2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the suction side profile.

[0017] According to one or more embodiments of the present invention, when n=4, point P s3 P can move freely in any direction. s4 At point P s5 The point moves along the tangent direction. During the movement, point P... s2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the suction side profile.

[0018] The positive and progressive effects of this invention are as follows:

[0019] The turbine support blade profile design method with continuous curvature of the present invention has at least the following advantages:

[0020] The present invention provides a turbine support blade design method with continuous curvature, which is used for the design of interstage casing support blades and aft casing support blades. It can achieve continuous curvature at the leading edge connection of the support blades and improve aerodynamic performance. Attached Figure Description

[0021] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0022] Figure 1 This is a schematic diagram of the turbine support blade.

[0023] Figure 2 This is a schematic flowchart of the turbine support blade airfoil design method with continuous curvature according to the present invention.

[0024] Figure 3 This is a schematic diagram of the elliptical leading edge and its tangent point in the turbine support blade airfoil design method with continuous curvature of the present invention.

[0025] Figure 4 This is a schematic diagram of the trailing edge calculation process in the turbine support blade airfoil design method with continuous curvature of the present invention.

[0026] Figure 5 This is a schematic diagram of the pressure side profile and suction side profile with the leading edge tangent point in the turbine support blade airfoil design method with continuous curvature of the present invention.

[0027] Figure 6 This is a schematic diagram of the tangent points between the pressure side profile and the suction side profile and the trailing edge in the turbine blade airfoil design method with continuous curvature of the present invention.

[0028] Figure 7 This is a schematic diagram of the pressure side profile formed by a third-order Bézier curve in the turbine support blade airfoil design method with continuous curvature of the present invention.

[0029] Figure 8 This is a schematic diagram of the pressure side profile formed by a fourth-order Bezier curve in the turbine support blade airfoil design method with continuous curvature of the present invention.

[0030] Figure 9 This is a schematic diagram of the suction side profile formed by a third-order Bézier curve in the turbine support blade airfoil design method of the present invention with continuous curvature.

[0031] Figure 10 This is a schematic diagram of the suction side profile formed by a fourth-order Bezier curve in the turbine support blade airfoil design method with continuous curvature of the present invention. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are illustrated in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts. Furthermore, although the terminology used herein is selected from commonly known and used terminology, some terms mentioned in this specification may have been chosen by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of the description herein. Moreover, the invention should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0034] like Figure 2 As shown, the present invention provides a method for designing turbine support blade profiles with continuous curvature, characterized in that the design method includes the following steps:

[0035] Step S1: Calculate the size and position of the leading edge ellipse;

[0036] Step S2: Calculate the tangent point between the chord 108 and the leading edge ellipse; calculate the tangent point between the leading edge ellipse and the forehead line 107; calculate the coordinates of the tangent points between the pressure side profile 103 and the suction side profile 104 and the leading edge 101.

[0037] Step S3: Calculate the coordinates of the center 114 of the trailing edge;

[0038] Step S4: Calculate the coordinates of the tangent points between the pressure side profile 103 and the suction side profile 104 and the trailing edge 102;

[0039] Step S5: Obtain the pressure side profile 103 and the suction side profile 104 based on the curvature constraints and control point coordinates;

[0040] Step S6: Obtain the leaf shape;

[0041] The geometric parameters input to the design method include: leading edge diameter, leading edge ellipticity, trailing edge diameter, mounting angle γ, inlet configuration angle β1, geometric outlet angle β2, and leading edge pressure side wedge angle α. lps Leading edge suction side wedge angle α lss caudal wedge angle α t axial chord length C ax .

[0042] The leading edge diameter is typically twice the minor axis of the leading edge ellipse; the leading edge ellipticity is typically the ratio of the major axis to the minor axis of the leading edge ellipse; and the trailing edge diameter is the diameter of the trailing edge small circle.

[0043] In the curvature-continuous turbine blade design method of the present invention, the turbine is an energy conversion device that converts thermal energy into mechanical energy; the blade shape refers to the cross-sectional shape of the blade; and curvature continuity means that the curvatures of two curves are equal at the connection point.

[0044] Figure 1 The diagram shows a turbine blade profile, divided into four curve segments: leading edge 101 (usually an elliptical arc), trailing edge 102 (usually a circular arc), pressure-side profile 103, and suction-side profile 104. Leading edge 101 and pressure-side profile 103 connect at the pressure-side tangent point, i.e., the third tangent point 105, and leading edge 101 and suction-side profile 104 connect at the suction-side tangent point, i.e., the fourth tangent point 106. The line parallel to the y-axis and tangent to the leading edge of the blade is the datum line 107, and the line tangent to both the leading edge 101 and trailing edge 102 is the chord line 108. The angle between the chord line 108 and the negative y-axis is the installation angle γ.

[0045] The present invention provides a curvature-continuous turbine support blade design method for the design of interstage casing support blades and aft casing support blades. This method removes the constraints on the blade throat and achieves curvature continuity at the leading edge connection.

[0046] In a preferred embodiment of the turbine support blade airfoil design method with continuous curvature of the present invention, the calculation process of step S1 includes:

[0047] Step S 11 Input the leading edge diameter, leading edge ellipticity, and inlet construction angle β1;

[0048] Step S 12 The expression for the leading edge ellipse is calculated based on the leading edge diameter, the leading edge ellipticity, and the inlet construction angle β1, and the size and position of the leading edge ellipse are determined.

[0049] The leading edge diameter is twice the length of the minor axis of the leading edge ellipse.

[0050] In a preferred embodiment of the turbine blade profile design method with continuous curvature of the present invention, the calculation process of step S2 includes:

[0051] Step S 21 Input installation angle γ, inlet construction angle, leading edge pressure side wedge angle α lps Leading edge suction side wedge angle α lss ;

[0052] Step S 22 ,like Figure 3 As shown, the direction of the chord 108 is obtained according to the installation angle γ. The two tangent points between the chord 108 and the leading edge ellipse are calculated according to the tangent relationship between the straight line and the ellipse. According to the physical position relationship between the leading edge and the trailing edge of the blade, the tangent point with the smaller y coordinate value is taken as the first tangent point 109. The first tangent point 109 is the tangent point between the chord 108 and the leading edge ellipse, that is, the tangent point between the chord 108 and the leading edge 101.

[0053] like Figure 3 As shown, based on the fact that the frontal line 107 is parallel to the y-axis, the two tangent points between the leading edge ellipse and the frontal line 107 are calculated according to the tangent relationship between the straight line and the ellipse. According to the physical position relationship between the leading edge and the trailing edge of the leaf shape, the tangent point with the smaller x-coordinate value is taken as the second tangent point 111. The second tangent point 111 is the tangent point between the frontal line 107 and the leading edge ellipse, which is also the tangent point between the frontal line 107 and the leading edge 101.

[0054] like Figure 5 As shown, based on the inlet construction angle, the direction of the major axis 116 of the leading edge ellipse is known, and it forms a leading edge pressure side wedge angle α with the major axis 116 of the leading edge ellipse counterclockwise. lps The second straight line 118 is tangent to the leading edge ellipse 101, forming the third tangency point 105; the leading edge pressure side wedge angle α lps That is Figure 5 The counterclockwise angle between the middle edge and the major axis 116 of the leading edge ellipse is 117.

[0055] The leading edge suction side wedge angle α is clockwise from the major axis 116 of the leading edge ellipse. lss The straight line 120 is tangent to the leading edge ellipse 101, forming the fourth tangency point 106; the leading edge suction side wedge angle α lss That is Figure 5 The clockwise angle between the middle edge and the major axis 116 of the leading edge ellipse is 119.

[0056] The third tangent point 105 is the tangent point between the pressure side profile 103 and the leading edge 101, and the fourth tangent point 106 is the tangent point between the suction side profile 104 and the leading edge 101. The coordinates of the third tangent point 105 and the fourth tangent point 106 are determined.

[0057] Simultaneously, the curvature k of the third tangent point 105 on the leading edge ellipse is calculated based on the expression of the leading edge ellipse. p And the curvature k of the fourth tangent point 106 on the leading edge ellipse. s .

[0058] In a preferred embodiment of the turbine blade profile design method with continuous curvature of the present invention, the calculation process of step S3 includes:

[0059] Step S 31 Input axial chord length C ax and tail edge diameter;

[0060] Step S 32 ,like Figure 4 As shown, based on the axial chord length C ax The second tangent point 111 is used to obtain the tangent point of the first straight line 115 in the direction of the trailing edge 102 and the frontal line 107 as the fifth tangent point 113. The X coordinate of the fifth tangent point 113 is determined, and the X coordinate of the fifth tangent point 113 is the same as that of the trailing edge center 114. The straight line expression of the chord 108 is obtained according to the chord 108 and the first tangent point 109. According to the trailing edge diameter and the tangency constraint between the circle and the straight line, two circles are obtained. According to the physical relationship between the leading edge and the trailing edge of the blade, the circle with the larger Y coordinate of the center is obtained as the trailing edge small circle, and the center coordinate of the trailing edge small circle is used as the coordinate of the trailing edge center 114. The axial chord length C ax That is Figure 4 The length of the value is 112.

[0061] In a preferred embodiment of the turbine support blade airfoil design method with continuous curvature of the present invention, the calculation process of step S4 includes:

[0062] Step S 41 Input geometric exit angle β2 and trailing edge wedge angle α t ;

[0063] Step S 42 ,like Figure 6As shown, the direction of the exit geometry line 121 is obtained based on the coordinates of the geometric exit angle β2 and the center of the trailing edge 114; the trailing edge wedge angle α is 1 / 2 clockwise from the exit geometry line 121. t The third straight line 123 is tangent to the small circle at the trailing edge, forming the sixth tangency point 124; it forms a trailing edge wedge angle α that is 1 / 2 counterclockwise with the exit geometry line 121. t The fourth straight line 125 is tangent to the small circle at the trailing edge, forming the seventh tangency point 126; determine the coordinates of the sixth tangency point 124 and the seventh tangency point 126; the trailing edge wedge angle α t That is Figure 6 The included angle is 122.

[0064] The sixth tangent point 124 is the tangent point between the pressure side profile 103 and the trailing edge 102, and the seventh tangent point 126 is the tangent point between the suction side profile 104 and the trailing edge 102.

[0065] like Figure 7 and Figure 8 As shown, in a preferred embodiment of the turbine blade profile design method with continuous curvature of the present invention, in step S5, the pressure side profile 103 is formed using an n-order Bézier curve (n≥3, and n is an integer). The pressure side profile 103 includes n+1 first control points 127, which are points P... p1 Point P p2 ... point P pn and point P p(n+1) The leading edge profile and the pressure side profile 103 meet at point P. p1 The trailing edge profile and the pressure side profile 103 are tangent at point P. p(n+1) Tangent at the point;

[0066] The curvature constraint method is based on point P p1 curvature k on leading edge 101 p1 The curvature formula of the Bézier curve is used to obtain point P. p2 The coordinate values;

[0067] Point P p1 The curvature k on the pressure-side profile 103 p1 The curvature of a Bézier curve satisfies the following formula:

[0068]

[0069] Among them, point P p2 Among the n+1 first control points 127, point P is... p1 Adjacent points, and point P p2 At point P p1 Move along the tangent line; point P p3 Among the n+1 first control points 127, point P is... p2Adjacent points, and point P p3 At point P p(n+1) Move along the tangent (when n=3) or point P p3 Move in any direction (when n>3); h p Let P be the point p3 Distance from point P p1 and point P p2 The perpendicular distance from the line in which it lies; a p Let P be the point p1 and point P p2 The distance between the line segments;

[0070] According to point P p3 Location and point P p1 The tangent direction can be used to calculate h. p a is obtained from equation (1) p The value of a, according to a p The value of point P is calculated. p2 The coordinate values.

[0071] like Figure 7 As shown, in a preferred embodiment of the turbine support blade airfoil design method with continuous curvature of the present invention, when n=3, P p3 At point P p4 The point moves along the tangent direction. During the movement, point P... p2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the pressure side profile 103.

[0072] Figure 7 The diagram shows a pressure-side profile 103 formed by a third-order Bézier curve, i.e., n=3. The pressure-side profile 103 is composed of a third-order Bézier curve and has four first control points 127, namely P... p1 P p2 P p3 P p4 Among them, P p1 P coincides with the third tangent point 105. p4 It coincides with the sixth tangent point 124.

[0073] When n=3, the curvature constraint method is based on point P. p1 curvature k on leading edge 101 p1 The curvature formula of the Bézier curve is used to obtain point P. p2 The coordinate values.

[0074] According to the formula for calculating the curvature of a Bézier curve, point P... p1 The curvature k on the pressure-side profile 103 p1 Satisfy the following formula:

[0075]

[0076] Among them, point P p2 Among the four first control points 127, point P is the only one that is not a control point. p1 Adjacent points, and point P p2 At point P p1 Move along the tangent line; point P p3 Among the four first control points 127, point P is the only one that is not a control point. p2 Adjacent points, and point P p3 At point P p4 Move along the tangent; h p Let P be the point p3 Distance from point P p1 and point P p2 The perpendicular distance from the line in which it lies; a p Let P be the point p1 and point P p2 The distance between the line segments;

[0077] According to point P p3 Location and point P p1 The tangent direction can be used to calculate h. p According to equation (2), a can be obtained. p The value of a, according to a p The value of point P is calculated. p2 The coordinate values.

[0078] Point P p3 At point P p4 The point moves along the tangent direction. During the movement, point P... p2 The coordinate values ​​are automatically calculated based on the curvature constraints described above, thereby controlling the geometry of the pressure-side profile 103. Under these curvature constraints, the pressure-side profile 103, formed by a third-order Bézier curve, has one degree of freedom, namely point P. p3 At point P p4 The degree of freedom of movement in the tangential direction.

[0079] like Figure 8 As shown, in a preferred embodiment of the turbine blade profile design method with continuous curvature of the present invention, when n=4, point P p3 P can move freely in any direction. p4 At point P p5 The tangential direction moves.

[0080] During the movement, point P p2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the pressure side profile 103.

[0081] Figure 8The diagram shows a pressure-side profile 103 formed by a fourth-order Bézier curve, i.e., n=4. The pressure-side profile 103 is composed of a fourth-order Bézier curve and has five first control points 127, namely P p1 P p2 P p3 P p4 P p5 .

[0082] When n=4, the curvature constraint method is based on point P. p1 curvature k on leading edge 101 p1 The curvature formula of the Bézier curve is used to obtain point P. p2 The coordinate values.

[0083] Point P p1 The curvature k on the pressure-side profile 103 p1 The curvature of a Bézier curve satisfies the following formula:

[0084]

[0085] Among them, point P p2 Among the five first control points 127, point P is the only one that is not a control point. p1 Adjacent points, and point P p2 At point P p1 Move along the tangent line; point P p3 Among the five first control points 127, point P is the only one that is not a control point. p2 Adjacent points, and point P p3 Move in any direction; h p Let P be the point p3 Distance from point P p1 and point P p2 The perpendicular distance from the line in which it lies; a p Let P be the point p1 and point P p2 The distance between the line segments;

[0086] According to point P p3 Location and point P p1 The tangent direction can be used to calculate h. p According to equation (3), a can be obtained. p The value of a, according to a p The value of point P is calculated. p2 The coordinate values.

[0087] Point P p3 It can move freely in any direction, P p4 At point P p5 The point moves along the tangent direction. During the movement, point P... p2The coordinate values ​​are automatically calculated based on the curvature constraints described above, thereby controlling the geometry of the pressure-side profile 103. Under these curvature constraints, the pressure-side profile 103, formed by a fourth-order Bézier curve, has three degrees of freedom, namely, point P. p3 Two degrees of freedom that can be moved arbitrarily and P p4 At point P p5 The degree of freedom of movement in the tangential direction.

[0088] like Figure 9 and Figure 10 As shown, in a preferred embodiment of the turbine blade profile design method with continuous curvature of the present invention, in step S5, the suction side profile 104 is formed using an n-order Bézier curve (n≥3, and n is an integer). The suction side profile 104 includes n+1 second control points 128, which are points P... s1 Point P s2 ... point P sn and point P s(n+1) The trailing edge profile and the suction side profile 104 meet at point P. s(n+1) Tangent at the point;

[0089] The curvature constraint method is based on point P s1 curvature k on leading edge 101 s1 The curvature formula of the Bézier curve is used to obtain point P. s2 The coordinate values;

[0090] Point P s1 The curvature k on the suction-side profile 104 s1 The curvature of a Bézier curve satisfies the following formula:

[0091]

[0092] Among them, point P s2 Among the n+1 second control points 128, point P s1 Adjacent points, and point P s2 At point P s1 Move along the tangent line; point P s3 Among the n+1 second control points 128, point P s2 Adjacent points, and point P s3 At point P p(n+1) Move along the tangent (when n=3) or point P s3 Move in any direction (when n>3); h s Let P be the point s3 Distance from point P s1 and point P s2 The perpendicular distance from the line in which it lies; a s Let P be the point s1 and point P s2 The distance between the line segments;

[0093] According to point P s3 Location and point P s1 The tangent direction can be used to calculate h. s a is obtained from equation (4). s The value of a, according to a s The value of point P is calculated. s2 The coordinate values.

[0094] like Figure 9 As shown, in a preferred embodiment of the turbine support blade airfoil design method with continuous curvature of the present invention, when n=3, P s3 At point P s4 The point moves along the tangent direction. During the movement, point P... s2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the suction side profile 104.

[0095] Figure 9 The diagram shows a suction side profile 104 formed by a third-order Bézier curve. The suction side profile 104 is composed of a third-order Bézier curve and has four second control points 128, namely P... s1 P s2 P s3 P s4 Among them, P s1 P coincides with the fourth tangent point 106. p4 It coincides with the seventh tangent point 126.

[0096] When n=3, the curvature constraint method is based on point p. s1 curvature k on leading edge 101 s1 The curvature formula of the Bézier curve is used to obtain the value of point p. s2 The coordinate values.

[0097] According to the formula for calculating the curvature of a Bézier curve, point P... s1 The curvature ks1 on the suction-side profile 104 satisfies the following formula:

[0098]

[0099] Among them, point P s2 Among the four second control points 128, point P is the only one that is not a control point. s1 Adjacent points, and point P s2 At point P s1 Move along the tangent line; point P s3 Among the four second control points 128, point P is the only one that is not a control point. s2 Adjacent points, and point P s3 At point P s4 Move along the tangent; h s Let P be the points3 Distance from point P s1 and point P s2 The perpendicular distance from the line in which it lies; a s Let P be the point s1 and point P s2 The distance between the line segments;

[0100] According to point P s3 Location and point P s1 The tangent direction can be used to calculate h. s According to equation (5), a can be obtained. s The value of a, according to a s The value of point P is calculated. s2 The coordinate values.

[0101] Point P s3 At point P s4 The point moves along the tangent direction. During the movement, point p... s2 The coordinate values ​​are automatically calculated based on the curvature constraints described above, thereby controlling the geometry of the suction side profile 104. Under these curvature constraints, the suction side profile 104, formed by a third-order Bézier curve, has one degree of freedom, namely point P. s3 At point P s4 The degree of freedom of movement in the tangential direction.

[0102] like Figure 10 As shown, in a preferred embodiment of the turbine blade profile design method with continuous curvature of the present invention, when n=4, point P s3 P can move freely in any direction. s4 At point P s5 The point moves along the tangent direction. During the movement, point P... s2 The coordinate values ​​are automatically solved based on the curvature constraints to control and obtain the geometry of the suction side profile 104.

[0103] Figure 10 The diagram shows the suction side profile 104 formed by a fourth-order Bézier curve, i.e., n=4, with five second control points 128, namely P s1 P s2 P s3 P s4 P s5 .

[0104] When n=4, the curvature constraint method is based on point p. s1 curvature k on leading edge 101 s The curvature formula of the Bézier curve is used to obtain the value of point p. s2 The coordinate values.

[0105] Point p s3 The curvature k on the suction-side profile 104p1 The curvature of a Bézier curve satisfies the following formula:

[0106]

[0107] Among them, point P s2 Among the five second control points 128, point P is the only one that is not a control point. s1 Adjacent points, and point P s2 At point P s1 Move along the tangent line; point P s3 Among the five second control points 128, point P is the only one that is not a control point. s2 Adjacent points, and point P s3 Move in any direction; h s Let P be the point s3 Distance from point P s1 and point P s2 The perpendicular distance from the line in which it lies; a s Let P be the point s1 and point P s2 The distance between the line segments;

[0108] According to point P s3 Location and point P s1 The tangent direction can be used to calculate h. s According to equation (6), a can be obtained. s The value of a, according to a s The value of point P is calculated. s2 The coordinate values.

[0109] Point P s3 It can move freely in any direction, P s4 At point P s5 The point moves along the tangent direction. During the movement, point P... s2 The coordinate values ​​are automatically calculated based on the curvature constraints described above, thereby controlling the geometry of the suction side profile 104. Under these curvature constraints, the suction side profile 104, formed by a fourth-order Bézier curve, has three degrees of freedom, namely, point P. s3 Two degrees of freedom that can be moved arbitrarily and P s4 At point P s5 The degree of freedom of movement in the tangential direction.

[0110] The present invention provides a turbine support blade design method with continuous curvature, which is used for the design of interstage casing support blades and aft casing support blades. It can achieve continuous curvature at the leading edge connection of the support blades and improve aerodynamic performance.

[0111] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method of designing a turbine vane profile with continuous curvature, characterized by, The design method comprises the following steps: S1, calculating the size and position of the leading edge ellipse; S2, calculating the tangent point of the chord line and the leading edge ellipse; calculating the tangent point of the leading edge ellipse and the brow line; calculating the tangent point coordinates of the pressure side line and the suction side line and the leading edge; S3, calculating the tail edge circle center coordinates; S4, calculating the tangent point coordinates of the pressure side line and the suction side line and the tail edge; S5, obtaining the pressure side line and the suction side line according to the curvature constraint and the control point coordinates; S6, obtaining the blade profile; The geometric parameters input by the design method comprise: the leading edge diameter, the leading edge ellipticity, the tail edge diameter, the installation angle, the inlet configuration angle, the geometric outlet angle, the leading edge pressure side wedge angle, the leading edge suction side wedge angle, the tail edge wedge angle and the axial chord length.

2. The method of camber-continuous turbine shroud airfoil design of claim 1, wherein, The calculation process of the step S1 comprises: S 11 , input leading edge diameter, leading edge ellipticity, and inlet configuration angle; S 12 An expression of the leading edge ellipse is calculated from the leading edge diameter, the leading edge ellipticity and the inlet configuration angle to determine the size and position of the leading edge ellipse.

3. The method of camber-continuous turbine shroud airfoil design of claim 2, wherein, The calculation process of the step S2 comprises: S 21 , input mounting angle, inlet configuration angle, leading edge pressure side wedge angle, leading edge suction side wedge angle; S 22 , the direction of the chord line is obtained according to the installation angle, two tangent points of the chord line and the leading edge ellipse are calculated according to the tangent relationship between the straight line and the ellipse, and the first tangent point of the chord line and the leading edge ellipse is taken as the tangent point with a smaller y coordinate value according to the physical position relationship between the leading edge and the trailing edge of the airfoil, Based on the fact that the brow line is parallel to the y-axis, the two tangent points of the leading edge ellipse and the brow line are calculated according to the tangent relationship between the straight line and the ellipse; according to the physical position relationship between the leading edge and the tail edge of the blade profile, the tangent point with the smaller x-coordinate value is taken as the second tangent point, which is the tangent point of the brow line and the leading edge ellipse; According to the fact that the inlet configuration angle is known, the direction of the major axis of the leading edge ellipse is counterclockwise to the second straight line with the leading edge ellipse major axis at the leading edge pressure side wedge angle, which is tangent to the leading edge ellipse, forming a third tangent point; The straight line with the leading edge ellipse major axis clockwise at the leading edge suction side wedge angle is tangent to the leading edge ellipse, forming a fourth tangent point; The third tangent point is the tangent point of the pressure side line and the leading edge ellipse, and the fourth tangent point is the tangent point of the suction side line and the leading edge ellipse, and the coordinates of the third tangent point and the fourth tangent point are determined; The curvatures of the third tangent point on the leading edge ellipse and the fourth tangent point on the leading edge ellipse are calculated according to the expression of the leading edge ellipse.

4. The method of camber-continuous turbine shroud airfoil design of claim 3, wherein, The calculation process of the step S3 comprises: S 31 , input axial chord and trailing edge diameter; S 32 , the second tangent point, the first tangent point of the chord line and the chord line is obtained as the fifth tangent point, the X coordinate of the fifth tangent point is determined, and the X coordinate of the fifth tangent point is the same as that of the tail edge center; the straight line expression of the chord line is obtained according to the chord line and the first tangent point; according to the tail edge diameter and the tangent constraint of the circle and the straight line, two circles are obtained, according to the physical relationship of the leading edge and the tail edge of the airfoil, the circle with larger Y coordinate of the center is obtained as the tail edge small circle, and the center coordinate of the tail edge small circle is taken as the tail edge center coordinate.

5. The method of camber-continuous turbine vane airfoil design of claim 4, wherein, The calculation process of the step S4 comprises: S 41 , inputting a geometric exit angle and a trailing edge wedge angle; S 42 , obtaining a direction of an outlet geometric line according to the geometric outlet angle and the tail edge circle center coordinate; a third straight line with a tail edge wedge angle of 1 / 2 clockwise to the outlet geometric line is tangent to the tail edge small circle to form a sixth tangent point; a fourth straight line with a tail edge wedge angle of 1 / 2 counterclockwise to the outlet geometric line is tangent to the tail edge small circle to form a seventh tangent point; and coordinates of the sixth tangent point and the seventh tangent point are determined; The sixth tangent point is the tangent point of the pressure side line and the tail edge, and the seventh tangent point is the tangent point of the suction side line and the tail edge.

6. The method of camber-continuous turbine vane airfoil design of claim 5, wherein, In the step S5, the pressure side profile is formed by using an n-th order Bezier curve (n≥3, and n is an integer), and the pressure side profile includes n+1 first control points, i.e., point P p1 , point P p2 , …, point P pn , and point P p(n+1) . The leading edge profile is tangent to the pressure side profile at point P p1 , and the trailing edge profile is tangent to the pressure side profile at point P p(n+1) . The method of curvature constraint is to obtain the coordinate value of point P according to the point P p1 The curvature k on the leading edge p1 , the coordinate value of point P is obtained by using the curvature formula of Bezier curve p2 ; Point P p1 Curvature k on the pressure side profile p1 The curvature calculation formula of the following Bezier curve is satisfied: Among them, point P p2 Among the n+1 first control points, point P p1 Adjacent points, and point P p2 At point P p1 Move along the tangent line; point P p3 Among the n+1 first control points, point P p2 Adjacent points, and point P p3 At point P p(n+1) Move along the tangent or point P p3 Move in any direction; h p Let P be the point p3 Distance from point P p1 and point P p2 The perpendicular distance from the line in which it lies; a p Let P be the point p1 and point P p2 The distance between the line segments; According to the position of point P p3 and the tangent direction of point P p1 , h p is calculated; according to the curvature calculation formula of the above-mentioned Bezier curve, the value of a p is calculated, and according to the value of a p , the coordinate value of point P p2 is calculated.

7. The method of camber-continuous turbine vane airfoil design of claim 6, wherein, n = 3, P p3 In the tangent direction of point P p4 , moving, the point P p2 According to the curvature constraint, the coordinate value is automatically solved, the geometry of the pressure side profile is controlled and obtained.

8. The method of camber-continuous turbine vane airfoil design of claim 6, wherein, n = 4, point P p3 freely moving in any direction, P p4 moving in the tangent direction of point P p5 , point P p2 According to the curvature constraint, the coordinate value is automatically solved, the geometry of the pressure side profile is controlled and obtained.

9. The method of camber-continuous turbine vane airfoil design of claim 5, wherein, In the step S5, the suction side profile is formed using an n-th order Bessel curve (n≥3, and n is an integer), and the suction side profile includes n+1 second control points, i.e., a point P s1 , a point P s2 , …, a point P sn , and a point P s(n+1) . The trailing edge profile is tangent to the suction side profile at the point P s(n+1) . The curvature constraint method is to obtain the coordinate value of point P according to the point P s1 The curvature k on the leading edge s1 , the coordinate value of point P is obtained by using the curvature formula of Bezier curve s2 ; Point P s1 Curvature k on the suction side profile s1 The curvature calculation formula of the following Bezier curve is satisfied: Among them, point P s2 Among the n+1 second control points, point P s1 Adjacent points, and point P s2 At point P s1 Move along the tangent line; point P s3 Among the n+1 second control points, point P s2 Adjacent points, and point P s3 At point P p(n+1) Move along the tangent or point P s3 Move in any direction; h s Let P be the point s3 Distance from point P s1 and point P s2 The perpendicular distance from the line in which it lies; a s Let P be the point s1 and point P s2 The distance between the line segments; According to the position of point P s3 and the tangent direction of point P s1 , h s is calculated; according to the curvature calculation formula of the above-mentioned Bezier curve, the value of a s is calculated; according to the value of a s , the coordinate value of point P s2 is calculated.

10. The method of camber-continuous turbine vane airfoil design of claim 9, wherein, n = 3, P s3 In the tangent direction of point P s4 , moving, the point P s2 According to the curvature constraint, the coordinate value is automatically solved, the geometry of the suction side profile is controlled and obtained.

11. The method of camber-continuous turbine vane airfoil design of claim 9, wherein, n = 4, point P s3 freely moves in any direction, P s4 in the tangent direction of point P s5 moves, point P s2 According to the curvature constraint, the coordinate value is automatically solved, the geometry of the suction side profile is controlled and obtained.

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