Turbine flow adjusting method based on small flaps

Abstract

The invention belongs to the field of aerodynamic thermodynamics of turbomachinery, and discloses a turbine flow adjusting method based on a small flap. The method comprises the following steps: firstly, selecting reference two-dimensional blade profile data of each blade profile section of the adjustable guide blade of the gas turbine, and designing according to a parameterization method to obtain flap parts of the front half part and the rear half part of each section of the two-dimensional new turbine blade profile; and then the two-dimensional blade profiles of the blade profile sections are stacked in the spanwise direction, and the front geometry and the rear three-dimensional small flap geometry of the new three-dimensional turbine blade are obtained. And finally, the small flaps are geometrically rotated and translated to different relative positions, so that the influence caused by the limitation of the turbine structure is reduced, and the turbine flow is further flexibly and effectively adjusted.

Description

Technical Field

[0001] The invention relates to the field of impeller machinery aerodynamic thermodynamics, and in particular to a turbine flow regulation method based on a small flap. Background Art

[0002] The power, speed and mass flow of gas turbines under design point conditions are well matched, and they have excellent working performance and good economy. However, in actual application, gas turbines cannot always operate under design conditions, resulting in serious waste of resources. Therefore, it is particularly important to improve the performance of gas turbines under non-design conditions. The variable geometry turbine has good adaptability to variable conditions. It controls the channel flow by adjusting the guide vane throat area, reduces the fuel consumption rate under partial load, improves the engine's starting characteristics and acceleration characteristics, improves the engine's aerodynamic performance, and adjusts the gas turbine to operate under appropriate conditions.

[0003] Through the combination of theoretical and experimental research on the feasibility of variable geometry turbine methods for gas turbines, the variable geometry turbine method with adjustable guide vane installation angle has been gradually determined. Gao et al. conducted an experimental study on a variable geometry turbine linear cascade in the paper entitled "Experimental and numerical investigations of tip clearance flow and loss in a variable geometry turbine cascade, Proceedings of the Institution of Mechanical Engineers [J]. Part A: Journal of Power and Energy". The tip clearance height was 1.1% and 2.2% of the blade span, and the setting angle was -6 degrees, 0 degrees and 6 degrees to reveal the flow characteristics related to the three-dimensional clearance and the local clearance. The variable geometry turbine guide vane installation angle is adjustable. By changing the guide vane installation angle and then changing the guide vane throat area, the turbine flow rate is controlled, thereby effectively adjusting and optimizing the matching characteristics between the various components of the gas turbine. However, the flow regulation method of the integral rotating guide vane currently used is not flexible enough and is greatly affected by the limitations of the turbine structure. In order to further improve the flow control capability of the turbine and reduce the impact of turbine structure limitations, a new turbine flow regulation method needs to be developed. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a turbine flow regulation method based on small flaps, which can further flexibly and effectively regulate the turbine flow and reduce the impact of turbine structure limitations.

[0005] To achieve the above purpose, the present invention adopts the following technical solution.

[0006] The present invention provides a turbine flow regulation method based on a small flap, which comprises the following steps:

[0007] A small flap based on an adjustable guide vane is designed according to the parameterization method of the Fuller flap of a general aircraft. The shape of the small flap is divided into 5 sections. The generation of the shape of each section of the small flap is controlled by the following elliptical equation:

[0008] y 2 +ax 2 +bxy+cx=0 (1)

[0009] The five wing sections of the small flap are all solved by solving the simultaneous equations of the coordinates of two points and the slope at one point to obtain the corresponding coefficients a, b, c;

[0010] 1) extracting the two-dimensional blade profile coordinates at each spanwise cross-section position of the three-dimensional blade profile of the guide vane respectively to obtain a reference two-dimensional blade profile;

[0011] 2) Design a curve for segmenting the reference blade profile. The curve is composed of five segments of elliptical curves. The control equations of each segment of the elliptical curve are:

[0012] y 2 +ax 2 +bxy+cx=0

[0013] Select point p1(x1,y1) at a certain position on the pressure surface of the reference blade, select point p2(x2,y2) at a certain length from the trailing edge of the guide vane inside the reference blade as the leading edge point of the designed curve, and translate the entire reference blade with point p2 as the reference so that point p2 is located at the origin (0,0). At this time, the flap point p2 automatically satisfies the infinite slope; select points p3(x3,y3), p4(x4,y4) and p5(x5,y5) inside the reference two-dimensional blade, and select points p4(x4,y4) and p5(x5,y5) at a certain distance from the trailing edge of the guide vane inside the reference blade. A point p6 (x6, y6) is selected at a position; the slopes at points p1 and p6 can be obtained by the slope of the reference blade curve at the points, then the control equation parameters of each segment of the curve can be obtained in turn according to the known point coordinates and slope values, and the final curve can be obtained by the ellipse control equation and the smooth connection condition; the front segment reference blade curve and the obtained ellipse curve together constitute the front half of the new turbine blade, and the rear segment reference blade curve and the obtained ellipse curve together constitute the flap part of the rear half of the new turbine blade;

[0014] 3) The reference two-dimensional blade profile of each cross section is processed in step 2) to obtain a new two-dimensional blade profile at each cross section;

[0015] 4) stacking the obtained new two-dimensional blade profiles at each cross section along the span direction to form a new three-dimensional turbine guide vane;

[0016] 5) installing the new turbine guide vane onto the axial flow turbine, wherein the flap portion of the new blade can be opened, closed and rotated;

[0017] 6) By changing the selection of the coordinates of each point p1-p6 in step 2), small flap structures of different shapes are designed; according to the flow regulation range requirements required for the operation of the turbine, small flap structures of different shapes and sizes are designed to meet the turbine design requirements of different flow regulation ranges.

[0018] Furthermore, in step 2), the curve is formed by connecting and combining 5 segments of elliptical curves, and the endpoints of the curve are p1-p6, respectively, wherein p1 is selected on the pressure surface of the reference two-dimensional blade profile; p2 is selected at a position inside the reference two-dimensional blade profile at a certain length from the trailing edge of the blade, as the leading edge point of the entire curve; p3-p5 are selected inside the reference two-dimensional blade profile; p6 is selected on the suction surface of the reference two-dimensional blade profile, and the designed elliptical curve ensures that it is tangent to the pressure surface curve of the original blade profile at p1, and tangent to the suction surface curve of the original blade profile at p6.

[0019] Furthermore, the slopes of the intersections of two adjacent wing segments in the wing segment remain equal.

[0020] Furthermore, in the second step, the specific operation process is as follows:

[0021] 1) The horizontal coordinate at the position of 30% axial chord length from the trailing edge of the guide vane of the reference blade is selected as the horizontal coordinate x2 of the leading edge point p2 of the designed flap. The height h between the suction surface and the pressure surface at x2 is obtained by interpolating the vertical coordinate corresponding to the horizontal coordinate at the position of 30% axial chord length on the reference blade. 10% h is selected to obtain the vertical coordinate y2 of point p2, thus obtaining the coordinate p2 (x2, y2) of the leading edge point of the small flap; the blade profile data of the suction surface of the guide vane and the blade profile data of the pressure surface are translated respectively, so that the coordinate (x2, y2) of the leading edge point p2 of the flap after translation is the origin (0, 0), then the flap point 2 automatically satisfies the slope of infinity;

[0022] 2) The trailing edge at the small flap point p1 has the same shape as the trailing edge of the guide vane and is tangent at point 1. Therefore, the horizontal coordinate at the position of 27% axial chord length from the trailing edge of the guide vane of the reference blade is selected as the horizontal coordinate x1 at the small flap point p1. The vertical coordinate y1 of the small flap point 1 is obtained by interpolation through the pressure surface data, thereby obtaining point p1 (x1, y1). The slope k1 at the flap point p1 is further obtained by interpolating points near the flap point p1;

[0023] 3) The translated pressure surface blade profile data and suction surface blade profile data are multiplied by the rotation matrix of the slope at the flap point p1, respectively, to obtain the rotated suction surface blade profile data A2 and pressure surface blade profile data B2, as shown in Figure 2 As shown;

[0024] 4) Select the horizontal coordinates at the positions of 23%, 20%, 15%, and 8% of the axial chord length from the trailing edge of the guide vane of the reference blade profile as the horizontal coordinates x3, x4, x5, and x6 of points p3, p4, p5, and p6, respectively, and obtain the vertical coordinates of each flap point by interpolating the corresponding suction surface and pressure surface blade profile data. The coordinates of the five flap points are: p1 (x1, y1), p2 (0, 0), p3 (x3, y3), p4 (x4, y4), p5 (x5, y5), and p6 (x6, y6);

[0025] 5) The coordinates (x5, y5) and (x6, y6) of flap point p5 and flap point p6 are known, and the slope at flap point p6 is obtained by interpolating points near flap point p6 through suction surface profile data A2. The coefficients of the curve equation of flap section 5 are a5, b5, and c5 respectively, and the obtained curve data of flap section 5 are expressed together with suction surface profile data A2 and pressure surface profile data B2;

[0026] 6) Given the coordinates (x4, y4) and (x5, y5) of flap point p4 and flap point p5 and the curve equation of flap section 5 y^+a5*x^2+b5*x*y+c5*x=0, first find the slope at flap point p5, and solve equation 1 to obtain the curve equation coefficients of flap section 4 as a4, b4, and c4, respectively, and express the obtained curve data of flap section 4 together with the curve data of flap section 5, suction surface blade profile data A2, and pressure surface blade profile data B2;

[0027] 7) The solution of the curve equations at flap sections 3, 2, and 1 is similar to that in 6) above. At this time, the curves of the five flap sections have been obtained respectively, among which flap section 5 is tangent to the reference guide vane suction surface at flap point p6, and flap section 1 is tangent to the reference guide vane pressure surface at flap point p1; the data of the five flap sections obtained by solving, the data of the suction surface blade profile data whose horizontal coordinate is greater than the horizontal coordinate x6 of the flap point p6, and the data of the pressure surface blade profile data whose horizontal coordinate is greater than the horizontal coordinate x1 of the flap point p1 are sequentially connected end to end to form a complete closed curve;

[0028] 8) multiplying the closed curve obtained in 7) above by the inverse matrix of the slope at the flap point p1 to obtain a rotated closed curve;

[0029] 9) Add the horizontal and vertical coordinates of each data on the closed curve obtained by rotating counterclockwise in the above 8) to the initial horizontal and vertical coordinates (x20, y20) of the flap point p2, and we can get a small flap designed according to the Fuller flap of general aircraft that can effectively control the flow of the turbine.

[0030] Compared with the prior art, the present invention has the following benefits:

[0031] The turbine flow regulation method based on the small flap at the trailing edge of the adjustable guide vane provided by the present invention divides the conventional turbine adjustable guide vane into two parts, wherein the front part is a fixed structure and does not need to be adjusted, and the rear part of the guide vane is designed to be similar to the structure of the flap of the wing of an aircraft, that is, a small flap structure. At the same time, by rotating and translating the small flap geometric structure at the rear of the guide vane to different relative positions, the throat area of ​​the guide vane can be flexibly changed, thereby further realizing flexible and effective regulation of the turbine flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the turbine flow regulation effect of the small flap of the present invention at different flap openings;

[0033] Figure 2 It is a parameterized schematic diagram of the small flap of the present invention;

[0034] Figure 3 Schematic diagram of the reference two-dimensional blade profile of each cross section of the present invention;

[0035] Figure 4 It is a schematic diagram of the front blade profile of the two-dimensional guide vane and the small flap curve of the present invention;

[0036] Figure 5 Schematic diagram of the guide vane blade profile and small flap curve of each cross section of the present invention;

[0037] Figure 6 It is a schematic diagram of the geometry of the front part of the guide vane and the geometry model of the three-dimensional small flap of the present invention;

[0038] Figure 7 It is a schematic diagram of the geometry of the three-dimensional small flap of the present invention at a certain relative position;

[0039] Figure 8 It is a schematic diagram of the three-dimensional structure of small flaps of different shapes and sizes of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be described in more detail below in conjunction with the drawings of the specification. It should be noted that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] The embodiment of the present invention provides a turbine flow regulation method based on a small flap, comprising the following steps:

[0042] According to the parameterization method of the Fuller flap of general aircraft, a small flap based on adjustable guide vanes is designed to effectively adjust the turbine flow. The flap shape is divided into 5 sections (S1, S2, S3, S4, S5), such as Figure 2The generation of the shape of each flap segment is controlled by the following ellipse equation:

[0043] y 2 +ax 2 +bxy+cx=0 (1)

[0044] Among them, the corresponding coefficients a, b, and c can be obtained by solving the simultaneous equations of the coordinates of two points and the slope at one of the points for the five wing sections of the flap. At the same time, in order to ensure the overall smoothness of the designed flap, the slopes at the intersection of two adjacent wing sections in the wing section are kept equal;

[0045] Step 1: Extract the 2D blade coordinates at each spanwise section of the 3D blade profile of the guide vane to obtain the reference 2D blade profile of each section, such as Figure 3 shown.

[0046] Step 2: Design the curve for segmenting the reference blade. The curve is composed of five segments of elliptical curves. The control equations of each segment of the elliptical curve are:

[0047] y 2 +ax 2 +bxy+cx=0,

[0048] 1) Select the horizontal coordinate at the position of 30% axial chord length from the trailing edge of the guide vane of the reference blade as the horizontal coordinate x2 of the leading edge point p2 of the designed flap. Interpolate the vertical coordinate corresponding to the horizontal coordinate at the position of 30% axial chord length on the reference blade to obtain the height h between the suction surface and the pressure surface at x2. Select 10% h to obtain the vertical coordinate y2 of point p2, and thus obtain the coordinate p2 (x2, y2) of the leading edge point of the small flap. Translate the blade profile data of the suction surface of the guide vane and the blade profile data of the pressure surface respectively, so that the coordinate (x2, y2) of the leading edge point p2 of the flap after the translation is the origin (0, 0), then the flap point 2 automatically satisfies the slope of infinity.

[0049] 2) The trailing edge at the small flap point p1 has the same shape as the trailing edge of the guide vane and is tangent to it at point 1. Therefore, the horizontal coordinate at the position of 27% axial chord length from the trailing edge of the guide vane of the reference blade profile is selected as the horizontal coordinate x1 at the small flap point p1. The vertical coordinate y1 of the small flap point 1 is obtained by interpolating the pressure surface data, thereby obtaining point p1 (x1, y1), and further interpolating the points near the flap point p1 to obtain the slope k1 at the flap point p1.

[0050] 3) The translated pressure surface blade profile data and suction surface blade profile data are multiplied by the rotation matrix of the slope at the flap point p1 to obtain the rotated suction surface blade profile data A2 and pressure surface blade profile data B2, as shown in Figure 2 shown.

[0051] 4) Select the horizontal coordinates at the positions of 23%, 20%, 15%, and 8% of the axial chord length from the trailing edge of the reference blade as the horizontal coordinates x3, x4, x5, and x6 of points p3, p4, p5, and p6, respectively, and interpolate the corresponding suction and pressure surface blade data to obtain the vertical coordinates of each flap point. The coordinates of the five flap points are: p1 (x1, y1), p2 (0, 0), p3 (x3, y3), p4 (x4, y4), p5 (x5, y5), and p6 (x6, y6).

[0052] 5) The coordinates (x5, y5) and (x6, y6) of flap point p5 and flap point p6 are known, and the slope at flap point p6 is obtained by interpolating the points near flap point p6 through suction surface profile data A2. According to equation 1, the coefficients of the curve equation of flap section 5 are respectively a5, b5, and c5. The obtained curve data of flap section 5 are expressed together with suction surface profile data A2 and pressure surface profile data B2.

[0053] 6) Given the coordinates (x4, y4) and (x5, y5) of flap point p4 and flap point p5 and the curve equation of flap section 5 y^+a5*x^2+b5*x*y+c5*x=0, first find the slope at flap point p5, and solve equation 1 to obtain the curve equation coefficients of flap section 4 as a4, b4, and c4, respectively. The obtained curve data of flap section 4 are expressed together with the curve data of flap section 5, the suction surface blade profile data A2, and the pressure surface blade profile data B2.

[0054] 7) Similarly, the solution of the curve equations at flap sections 3, 2, and 1 is similar to the above 6). At this point, the curves of the five flap sections have been obtained, among which flap section 5 is tangent to the reference guide vane suction surface at flap point p6, and flap section 1 is tangent to the reference guide vane pressure surface at flap point p1. The data of the five flap sections obtained by solving, the data in the suction surface blade profile data whose horizontal coordinate is greater than the horizontal coordinate x6 of flap point p6, and the data in the pressure surface blade profile data whose horizontal coordinate is greater than the horizontal coordinate x1 of flap point p1 are sequentially connected end to end to form a complete closed curve.

[0055] 8) Multiply the closed curve obtained in 7) above by the inverse matrix of the slope at the flap point p1 to obtain a rotated closed curve.

[0056] 9) Add the horizontal and vertical coordinates of each data on the closed curve obtained by counterclockwise rotation of the above 8) to the initial horizontal and vertical coordinates (x20, y20) of the flap point p2, and we can get the small flap designed according to the general aircraft Fuller flap that can effectively control the flow of the turbine, such as Figure 4 shown.

[0057] Step 3: According to the complexity of the original turbine three-dimensional blade, select 3 to 11 spanwise sections of the two-dimensional blade profile for the second step design to obtain a new two-dimensional blade profile for each section.

[0058] Step 4: The two-dimensional blade profile obtained in the third step is stacked along the span direction to obtain a three-dimensional turbine guide vane with a small flap structure, such as Figure 6 shown.

[0059] Step 5: Install the new turbine guide vane onto the axial flow turbine, wherein the flap portion of the new blade can be opened, closed and rotated; by adjusting the position and angle of the small flap, the turbine flow rate can be flexibly adjusted under different working conditions, such as Figure 7 shown.

[0060] Step 6: By changing the selection of the coordinates of each point p1-p6 in the second step of the design process, small flap structures of different shapes can be flexibly designed. According to the flow adjustment range required for the turbine to work, the small flap structures of different shapes and sizes can be specifically designed to meet the turbine design requirements of different flow adjustment ranges, such as Figure 8 shown.

[0061] The curve is formed by connecting and combining 5 segments of elliptical curves, and the endpoints of the curve are p1-p6, wherein p1 is selected on the pressure surface of the reference two-dimensional blade profile; p2 is selected at a position inside the reference two-dimensional blade profile at a certain length from the trailing edge of the blade, as the leading edge point of the entire curve; p3-p5 are selected inside the reference two-dimensional blade profile; p6 is selected on the suction surface of the reference two-dimensional blade profile. The designed elliptical curve ensures that it is tangent to the pressure surface curve of the original blade profile at p1 and tangent to the suction surface curve of the original blade profile at p6.

[0062] Figure 1 The flow rate regulation effect of the small flap of the present invention on the turbine at different flap openings is shown in the figure. It can be seen from the figure that as the flap opening of the adjustable guide vane small flap gradually increases from 8% to 84%, the variable geometry turbine throat area gradually decreases, resulting in the flow rate through the turbine flow channel gradually decreasing from 3.85kg / s to 1.87kg / s. This shows that the small flap at different flap openings based on the adjustable guide vane has a good flow regulation effect on the turbine.

[0063] The turbine flow regulation method based on the small flap at the trailing edge of the adjustable guide vane of the present invention divides the conventional turbine adjustable guide vane into two parts, wherein the front part is a fixed structure and does not need to be adjusted, and the rear part of the guide vane is designed to be similar to the structure of the flap of the wing of an aircraft, that is, a small flap structure. At the same time, by rotating and translating the small flap geometric structure at the rear of the guide vane to different relative positions, the throat area of ​​the guide vane can be flexibly changed, thereby further realizing flexible and effective regulation of the turbine flow.

[0064] It should be noted that the above-described embodiments are only preferred embodiments of the present invention. For ordinary method personnel in the field of the present invention, the present invention can be modified, improved and replaced by equivalents without departing from the principles of the present invention, and these modifications, improvements and equivalent replacements are also considered to fall within the scope of protection of the claims of the present invention.

Claims

1. A turbine flow regulation method based on a small flap, characterized in that: The steps include: According to the parameterization method of the Fuller flap of general aircraft, a small flap based on an adjustable guide vane is designed, and the flap shape is divided into 5 sections. The generation of the shape of each section of the flap is controlled by the following elliptical equation: y 2 +ax 2 +bxy+cx=0(1) The five wing sections of the flap are all solved by solving the simultaneous equations of the coordinates of two points and the slope at one point to obtain the corresponding coefficients a, b, c; Step 1: extract the 2D blade profile coordinates at each spanwise section of the 3D blade profile of the guide vane, and obtain the reference 2D blade profile of each section; Step 2: Design the curve for segmenting the reference blade. The curve is composed of five segments of elliptical curves. The control equations of each segment of the elliptical curve are: y 2 +ax 2 +bxy+cx=0 Select point p1(x1,y1) at a certain position on the pressure surface of the reference blade, select point p2(x2,y2) at a certain length from the trailing edge of the guide vane inside the reference blade as the leading edge point of the designed curve, and translate the entire reference blade with point p2 as the reference so that point p2 is located at the origin (0,0). At this time, the flap point p2 automatically satisfies the infinite slope; select points p3(x3,y3), p4(x4,y4) and p5(x5,y5) inside the reference two-dimensional blade, and select points p4(x4,y4) and p5(x5,y5) at a certain distance from the trailing edge of the guide vane inside the reference blade. A point p6 (x6, y6) is selected at a position; the slopes at points p1 and p6 can be obtained by the slope of the reference blade curve at the points, then the control equation parameters of each segment of the curve can be obtained in turn according to the known point coordinates and slope values, and the final curve can be obtained by the ellipse control equation and the smooth connection condition; the front segment reference blade curve and the obtained ellipse curve together constitute the front half of the new turbine blade, and the rear segment reference blade curve and the obtained ellipse curve together constitute the flap part of the rear half of the new turbine blade; Step 3: According to the complexity of the original turbine three-dimensional blade, take 3 to 11 spanwise sections of the two-dimensional blade profile and perform the design in the second step above to obtain a new two-dimensional blade profile for each section; Step 4: stacking the two-dimensional blade profile obtained in the third step along the span direction to obtain a three-dimensional turbine guide vane with a small flap structure; Step 5: installing the new turbine guide vane onto the axial flow turbine, wherein the flap portion of the new blade can be opened, closed and rotated; Step 6: By changing the selection of coordinates of points p1-p6 in the second step, small flap structures of different shapes are designed; according to the flow regulation range requirements required for the operation of the turbine, small flap structures of different shapes and sizes are designed to meet the turbine design requirements of different flow regulation ranges.

2. The turbine flow regulation method based on small flaps according to claim 1, characterized in that: In the second step, the curve is formed by connecting and combining 5 segments of elliptical curves, and the endpoints of the curve are p1-p6, wherein p1 is selected on the pressure surface of the reference two-dimensional blade profile; p2 is selected at a position inside the reference two-dimensional blade profile at a certain length from the trailing edge of the blade, as the leading edge point of the entire curve; p3-p5 are selected inside the reference two-dimensional blade profile; p6 is selected on the suction surface of the reference two-dimensional blade profile. The designed elliptical curve ensures that it is tangent to the pressure surface curve of the original blade profile at p1 and tangent to the suction surface curve of the original blade profile at p6.

3. The turbine flow regulation method based on small flaps according to claim 1, characterized in that: The slopes at the intersection points of two adjacent wing segments among the wing segments are kept equal.

4. The turbine flow regulation method based on small flaps according to claim 1, characterized in that: In the second step, the specific operation process is as follows: 1) The horizontal coordinate at the position of 30% axial chord length from the trailing edge of the guide vane of the reference blade is selected as the horizontal coordinate x2 of the leading edge point p2 of the designed flap. The height h between the suction surface and the pressure surface at x2 is obtained by interpolating the vertical coordinate corresponding to the horizontal coordinate at the position of 30% axial chord length on the reference blade. 10% h is selected to obtain the vertical coordinate y2 of point p2, thus obtaining the coordinate p2 (x2, y2) of the leading edge point of the small flap; the blade profile data of the suction surface of the guide vane and the blade profile data of the pressure surface are translated respectively, so that the coordinate (x2, y2) of the leading edge point p2 of the flap after translation is the origin (0, 0), then the flap point 2 automatically satisfies the slope of infinity; 2) The trailing edge at the small flap point p1 has the same shape as the trailing edge of the guide vane and is tangent at point 1. Therefore, the horizontal coordinate at the position of 27% axial chord length from the trailing edge of the guide vane of the reference blade is selected as the horizontal coordinate x1 at the small flap point p1. The vertical coordinate y1 of the small flap point 1 is obtained by interpolation through the pressure surface data, thereby obtaining point p1 (x1, y1). The slope k1 at the flap point p1 is further obtained by interpolating points near the flap point p1; 3) Multiplying the translated pressure surface blade profile data and suction surface blade profile data by the rotation matrix of the slope at flap point p1 respectively to obtain the rotated suction surface blade profile data A2 and pressure surface blade profile data B2; 4) Select the horizontal coordinates at the positions of 23%, 20%, 15%, and 8% of the axial chord length from the trailing edge of the guide vane of the reference blade profile as the horizontal coordinates x3, x4, x5, and x6 of points p3, p4, p5, and p6, respectively, and obtain the vertical coordinates of each flap point by interpolating the corresponding suction surface and pressure surface blade profile data. The coordinates of the five flap points are: p1 (x1, y1), p2 (0, 0), p3 (x3, y3), p4 (x4, y4), p5 (x5, y5), and p6 (x6, y6); 5) The coordinates (x5, y5) and (x6, y6) of flap point p5 and flap point p6 are known, and the slope at flap point p6 is obtained by interpolating points near flap point p6 through suction surface profile data A2. The coefficients of the curve equation of flap section 5 are a5, b5, and c5 respectively, and the obtained curve data of flap section 5 are expressed together with suction surface profile data A2 and pressure surface profile data B2; 6) Given the coordinates (x4, y4) and (x5, y5) of flap point p4 and flap point p5 and the curve equation of flap section 5 y^+a5*x^2+b5*x*y+c5*x=0, first find the slope at flap point p5, and solve equation 1 to obtain the curve equation coefficients of flap section 4 as a4, b4, and c4, respectively, and express the obtained curve data of flap section 4 together with the curve data of flap section 5, suction surface blade profile data A2, and pressure surface blade profile data B2; 7) The solution of the curve equations at flap sections 3, 2, and 1 is similar to that in 6) above. At this time, the curves of the five flap sections have been obtained respectively, among which flap section 5 is tangent to the reference guide vane suction surface at flap point p6, and flap section 1 is tangent to the reference guide vane pressure surface at flap point p1; the data of the five flap sections obtained by solving, the data of the suction surface blade profile data whose horizontal coordinate is greater than the horizontal coordinate x6 of the flap point p6, and the data of the pressure surface blade profile data whose horizontal coordinate is greater than the horizontal coordinate x1 of the flap point p1 are sequentially connected end to end to form a complete closed curve; 8) multiplying the closed curve obtained in 7) above by the inverse matrix of the slope at the flap point p1 to obtain a rotated closed curve; 9) Add the horizontal and vertical coordinates of each data on the closed curve obtained by rotating counterclockwise in the above 8) to the initial horizontal and vertical coordinates (x20, y20) of the flap point p2, and we can get a small flap designed according to the Fuller flap of general aircraft that can effectively control the flow of the turbine.

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