A turbine transition section meridian flow channel profile design method

Abstract

The application discloses a turbine transition section meridian flow channel profile design method, comprising the following steps: giving transition section design input; calculating transition section dimensionless parameter; judging rationality of transition section parameter; evaluating aerodynamic performance of the transition section; designing transition section meridian flow channel profile; calculating through-flow area of different positions of the transition section; and analyzing through-flow area relation curve of the turbine transition section until the through-flow area relation curve of the turbine transition section becomes a state of gently increasing. According to the characteristics of the turbine transition section meridian flow channel profile, the preliminary performance evaluation process is advanced, which is beneficial to accelerating the turbine transition section meridian flow channel profile design process and realizing the turbine transition section meridian flow channel profile meeting the aerodynamic performance requirement more quickly.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine performance evaluation, and specifically relates to a method for designing the meridional flow channel profile of the turbine transition section. Background Technology

[0002] In dual-rotor and triple-rotor gas turbines, the turbines of different rotors are often connected by a meridional expansion turbine transition section, which transports high-temperature gas from the turbine of the preceding rotor to the turbine of the following rotor. To simplify the structure, reduce the number of parts, and shrink the engine size, dual-rotor and triple-rotor gas turbines often arrange cooling air supply channels or pipelines, lubricating oil supply and return channels or pipelines in the support plates / supports or fairings of the turbine transition section. Some engines arrange both large and small support plates in the turbine transition section, with the small support plate used for load-bearing support and the large support plate used as a passage for lubricating oil and cooling air.

[0003] The aerodynamic performance of the turbine transition section directly affects the overall performance of the gas turbine. Therefore, it is of great significance to quickly obtain a turbine transition section with excellent aerodynamic performance and design a high-performance turbine to improve the efficiency of gas turbines.

[0004] Currently, a large amount of research focuses on turbine aerodynamic performance design and optimization, with significantly less attention paid to and researched on the turbine transition section. Research on the turbine transition section mostly concentrates on how to use full three-dimensional design methods to optimize the meridional channel profile and support profile of the turbine transition section with a single support plate. There is insufficient attention paid to the low-dimensional rapid assessment of the aerodynamic performance of the turbine transition section.

[0005] Since the aerodynamic performance of the turbine transition section and turbine blades has the same impact on the overall performance of the gas turbine—meaning that reducing the losses in both by the same amount will result in the same increase in overall efficiency—and while turbine blade aerodynamic performance has already reached a high level, research on the aerodynamic performance of the turbine transition section is relatively limited. Therefore, how to further reduce the losses in the turbine transition section is a pressing issue for designers. Currently, designers use full three-dimensional computational analysis to evaluate the aerodynamic performance of the turbine transition section. Full three-dimensional computational analysis is a high-dimensional design method, and its evaluation process is complex and time-consuming. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for designing the meridional flow profile of the turbine transition section. Based on the characteristics of the meridional flow profile of the turbine transition section, the preliminary performance evaluation process is advanced, accelerating the acquisition of a turbine transition section meridional flow profile that meets aerodynamic performance requirements.

[0007] The objective of this invention is achieved through the following technical solution: a method for designing the meridional flow channel profile of a turbine transition section, comprising the following steps:

[0008] Step 1: Determine the axial width and flow path of the turbine transition section based on the axial dimension space requirements and constraints of the gas turbine and turbine components;

[0009] Step 2: Calculate the dimensionless parameters of the turbine transition section based on the axial width and flow path dimensions of the turbine transition section obtained in Step 1;

[0010] Step 3: Judge the rationality of the dimensionless parameters obtained in Step 2. If they meet the requirements, proceed to Step 4. If they do not meet the requirements, adjust the axial width and flow dimensions of the turbine transition section determined in Step 1.

[0011] Step 4: Based on the dimensionless parameters of the turbine transition section obtained in Step 3, and the corresponding transition section characteristic curve, obtain the static pressure coefficient C of the transition section. P ;

[0012] Step 5: The static pressure coefficient C of the transition section obtained in Step 4 P If the design requirements are met, proceed to step 6; when the static pressure coefficient C of the transition section... P If the design requirements are not met, adjust the axial width of the transition section in step 1 and repeat steps 1 to 5.

[0013] Step 6: Based on the axial width and flow dimensions of the transition section determined in Step 1, and in conjunction with the Bezier curve, construct the inner and outer flow profiles of the meridional channel of the turbine transition section;

[0014] Step 7: Based on the inner and outer flow profiles of the meridional channel of the turbine transition section constructed in Step 6, calculate the flow area at different positions of the transition section to obtain the flow area relationship curve of the turbine transition section.

[0015] Step 8: Using the flow area relationship curve of the turbine transition section obtained in Step 7, determine whether there is a sudden increase or decrease in the flow area in the curve. If so, adjust the control points of the Bezier curves of the inner and outer flow profiles of the meridional channel of the turbine transition section to adjust the flow area relationship curve of the turbine transition section until the flow area relationship curve of the turbine transition section is in a state of gradual increase.

[0016] Preferably, in step 1, based on the maximum permissible axial width L of the turbine transition section z，max Determine the axial width L of the turbine transition section z According to the radius R of the outlet flow root of the upstream component of the gas turbine turbine. h，in Top radius R t，in Dimensions, downstream component inlet flow root radius R h，out Top radius R t，out Determine the turbine transition section flow path dimensions based on dimensional requirements, including the inlet root radius R. h，inInlet top radius R t，in Imported area A in The root radius of the outlet is R. h，out The top radius of the outlet is R. t，out Export area A out Given the total pressure at the inlet of the transition section Imported static pressure p in Import flow G in .

[0017] Preferably, in step 2, the dimensionless parameters include the transition section diffuser ratio k, the equivalent expansion angle α, the inlet hub ratio v, and the relative outlet radius. and relative axial length The aforementioned dimensionless parameters are calculated using the axial width of the transition section and the flow dimensions determined in step 2, as shown in equations (1) to (5):

[0018]

[0019]

[0020]

[0021]

[0022]

[0023] Preferably, in step 3, the rationality judgment condition includes: the transition section diffusion ratio k ≥ 1.

[0024] Preferably, in step 4, the static pressure coefficient C of the transition section is... P We obtain the following from equation (6):

[0025]

[0026] Where, p in For imported static pressure, p out For outlet static pressure, This is the total import pressure.

[0027] Preferably, in step 5, when the static pressure coefficient C of the transition section... P If the design requirements are not met, the constructed transition section model can be adjusted by increasing or decreasing the axial width of the transition section.

[0028] Preferably, in step 6, the axial width L of the turbine transition section determined in step 1 is... z , Inlet root radius R h，in Inlet top radius R t，in , Exit root radius R h，out , Exit top radius Rt，out The inner and outer flow profiles of the meridional channel in the turbine transition section are constructed using Bézier curves, where the Bézier curves are shown in equation (7):

[0029]

[0030] In the formula, P(t) represents the coordinates of any point on the Bézier curve, n represents the order of the Bézier curve, and i represents the current order, i = 0, 1, 2, ..., n; p i B is the position vector of each vertex; i，n (t) is a Bernstein basis function:

[0031]

[0032] Where i = 0, 1, 2, ..., n, t is the curve parameter variable, 0 ≤ t ≤ 1.

[0033] Preferably, in step 7, the method for obtaining the flow area relationship curve of the turbine transition section includes: calculating the flow centerline of the turbine transition section based on the inner and outer flow profiles of the meridional channel obtained in step 6, i.e., the curve formed by points equidistant from the inner and outer flow profiles of the meridional channel along the airflow direction; arranging 20-40 flow area measurement points i at equal intervals along the flow centerline of the turbine transition section along the airflow direction, and calculating the flow area A of the turbine transition section at each measurement point. i Plot the curve L, where the horizontal axis represents the length of the flow area measurement point at the centerline of the turbine transition section from the starting point to the horizontal axis. i The vertical axis represents the flow area A of the turbine transition section at the measurement point. i Relationship curve.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] This invention provides a method for designing the meridional flow profile of a turbine transition section. Based on the characteristics of the meridional flow profile of the turbine transition section, this method reorganizes and standardizes its design process, advancing the preliminary performance evaluation process and accelerating the design process to obtain a turbine transition section meridional flow profile that meets aerodynamic performance requirements more quickly. Using the rapid design method for the turbine transition section meridional flow profile proposed in this invention, the entire design process can be automated without manual intervention. Combined with the parametric design of the turbine transition section fairing and struts, parametric design and calculation analysis of the turbine transition section can be achieved, laying a solid foundation for rapid optimization design of the turbine transition section.

[0036] The proposed method for rapid design of the meridional flow profile of the turbine transition section enables rapid evaluation of the aerodynamic performance of the meridional flow profile of the turbine transition section using fewer dimensionless parameters. This achieves low-dimensional and rapid analysis of the aerodynamic performance of the meridional flow profile of the turbine transition section, avoiding high-dimensional, long-term, and multi-round iterative design, and fundamentally solving the problem of long cycle in traditional full three-dimensional calculation and analysis. Attached Figure Description

[0037] Figure 1 This is a flowchart of a turbine transition section meridional flow channel profile design method according to the present invention;

[0038] Figure 2 A schematic diagram of the turbine transition section flow path structure and dimensions in an embodiment of the present invention;

[0039] Figure 3 Schematic diagram of the transition section characteristic curve in an embodiment of the present invention;

[0040] Figure 4 This is a schematic diagram of the cross-section calculation position in an embodiment of the present invention.

[0041] Figure 5 This is the flow area relationship curve of the turbine transition section in this embodiment of the invention;

[0042] Figure 6 In this embodiment of the invention, the flow area A of the turbine transition section at the measurement point is... i Relationship curve;

[0043] Figure 7 This is a schematic diagram of the control points for the Bézier curve in an embodiment of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0045] like Figure 1 As shown, the technical solution of the present invention provides a method for designing the meridional flow channel profile of a turbine transition section, comprising the following steps:

[0046] Step 1: Determine the flow path dimensions (inlet and outlet inner and outer diameters) and axial width of the transition section based on the outlet size and location of the low-pressure gas turbine (transition section inlet) and the inlet size and location of the power turbine (transition section outlet), such as... Figure 2As shown. The total temperature, total pressure, and flow rate parameters at the inlet of the transition section are calculated overall. Based on the axial dimension space requirements and constraints of the gas turbine and turbine components, the axial width and flow path of the turbine transition section are determined, specifically: based on the allowable maximum axial width L of the turbine transition section. z，max Determine the axial width L of the turbine transition section z According to the radius R of the outlet flow root of the upstream component of the gas turbine turbine. h，in Top radius R t，in Dimensions, downstream component inlet flow root radius R h，out Top radius R t，out Determine the turbine transition section flow path dimensions based on dimensional requirements, including the inlet root radius R. h，in Inlet top radius R t，in Imported area A in The root radius of the outlet is R. h，out The top radius of the outlet is R. t，out Export area A out Given the total pressure at the inlet of the transition section Imported static pressure p in Import flow G in .

[0047] Step 2: Calculate the dimensionless parameters of the turbine transition section based on the axial width and flow dimensions obtained in Step 1, including the transition section diffuser ratio k, equivalent expansion angle α, inlet hub ratio v, and relative outlet radius. and relative axial length The aforementioned dimensionless parameters are calculated using the axial width of the transition section and the flow dimensions determined in step 2, as shown in equations (1) to (5):

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] The aforementioned dimensionless parameters are used for subsequent aerodynamic performance evaluation of the transition section.

[0054] Step 3: Judge the rationality of the dimensionless parameters obtained in Step 2. If they meet the requirements, proceed to Step 4. If they do not meet the requirements, adjust the axial width and flow path of the turbine transition section determined in Step 1: Based on the diffuser ratio k of the transition section calculated in Step 2, judge the rationality of the transition section parameters. If k ≥ 1, the parameters are reasonable, and proceed to Step 4; if k < 1, adjust the root radius R of the inlet in Step 1. h，in Inlet top radius R t，in , Exit root radius R h，out , Exit top radius R t，out , such that k≥1.

[0055] Step 4: Based on the dimensionless parameters of the turbine transition section obtained in Step 3, the corresponding parameters are as follows: Figure 3 The transition section characteristic curve shown yields the static pressure coefficient C of the transition section. P :

[0056] static pressure coefficient C of the transition section P We obtain the following from equation (6):

[0057]

[0058] Where, p in For imported static pressure, p out For outlet static pressure, For the total inlet pressure, specifically, the dimensionless parameters of the transition section diffusion ratio k and the relative axial length are used. The x-axis k-1 and y-axis of the transition section characteristic curve can be obtained. C is the intersection of the x and y axes on the characteristic curve. P The value is the static pressure coefficient of the transition section.

[0059] Step 5: The static pressure coefficient C of the transition section obtained in Step 4 P If the design requirements are met, proceed to step 6, for example, C. P ≥0.45; when the static pressure coefficient C of the transition section P If the design requirements are not met, adjust the axial width of the transition section in step 1 and repeat steps 1 to 3.

[0060] Step 6: Based on the axial width and flow dimensions of the transition section determined in Step 1, and in conjunction with the Bézier curve, construct the inner and outer flow profiles of the meridional channel of the turbine transition section. The specific method is as follows:

[0061] The inlet and outlet flow dimensions of the transition section determined in step 1, namely the axial and radial dimensions of the inlet and outlet of the inner flow profile of the meridional channel and the axial and radial dimensions of the inlet and outlet of the outer flow profile of the meridional channel, are the starting points of the inner and outer flow profiles of the meridional channel of the transition section. They are connected by a Bezier curve. By controlling the control points of the Bezier curve, the AUTOBLADE airfoil design software is used to construct relatively smooth inner and outer flow profiles.

[0062] Based on the axial width L of the turbine transition section determined in step 1 z , Inlet root radius R h，in Inlet top radius R t，in , Exit root radius R h,out , Exit top radius R t,out The hub and shroud profiles of the meridional channel in the turbine transition section are constructed using Bézier curves, where the Bézier curve is shown in equation (7):

[0063]

[0064] In the formula, P(t) represents the coordinates of any point on the Bézier curve, n represents the order of the Bézier curve, and i represents the current order, i = 0, 1, 2, ..., n; p i B is the position vector of each vertex; i,n (t) is a Bernstein basis function:

[0065]

[0066] Where i = 0, 1, 2, ..., n, t is the curve parameter variable, 0 ≤ t ≤ 1.

[0067] Step 7: As Figure 4 As shown, based on the inner and outer flow profiles of the meridional channel of the turbine transition section constructed in step 6, the flow area at different positions of the transition section is calculated, and the flow areas at sections 1 to 2 are calculated sequentially along the axial width direction. Figure 4 In the calculation, the cross-sectional position is shown as A1-An. A plot is drawn with the horizontal axis representing the axial width of the turbine transition section and the vertical axis representing the cross-sectional area, yielding the flow area relationship curve of the turbine transition section, as shown below. Figure 5 As shown. Based on the inner and outer flow profiles of the meridional channel in the turbine transition section obtained in step 6, the flow centerline of the turbine transition section is calculated. This is the curve formed by points equidistant from the inner and outer flow profiles along the airflow direction within the meridional channel. 20-40 flow area measurement points i are evenly spaced along the flow centerline of the turbine transition section along the airflow direction, and the flow area A of the turbine transition section at each measurement point is calculated. iPlot the curve L, where the horizontal axis represents the length of the flow area measurement point at the centerline of the turbine transition section from the starting point to the horizontal axis. i The vertical axis represents the flow area A of the turbine transition section at the measurement point. i Relationship curve, such as Figure 6 As shown.

[0068] Step 8: Using the flow area relationship curve of the turbine transition section obtained in Step 7, determine whether there is a sudden increase or decrease in the flow area in the curve. If not, the design of the flow profiles inside and outside the transition section is complete. If so, adjust the control points of the Bezier curves of the flow profiles inside and outside the meridional channel of the turbine transition section, such as... Figure 7 As shown, by adjusting the control points of the Bezier curve, the flow profiles inside and outside the meridional channel of the transition section will change, and the flow area of ​​the transition section will also change accordingly. This will adjust the flow area relationship curve of the turbine transition section until the flow area relationship curve of the turbine transition section is in a state of gradual increase.

[0069] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for designing the meridional flow channel profile of a turbine transition section, characterized in that: The method includes the following steps: Step 1: Determine the axial width and flow path of the turbine transition section based on the axial dimension space requirements and constraints of the gas turbine and turbine components; Step 2: Calculate the dimensionless parameters of the turbine transition section based on the axial width and flow path dimensions of the turbine transition section obtained in Step 1; Step 3: Judge the rationality of the dimensionless parameters obtained in Step 2. If they meet the requirements, proceed to Step 4. If they do not meet the requirements, adjust the axial width and flow dimensions of the turbine transition section determined in Step 1. Step 4: Based on the dimensionless parameters of the turbine transition section obtained in Step 3, and the corresponding transition section characteristic curve, obtain the static pressure coefficient C of the transition section. P ; Step 5: The static pressure coefficient C of the transition section obtained in Step 4 is... P If the design requirements are met, proceed to step 6; when the static pressure coefficient C of the transition section... P If the design requirements are not met, adjust the axial width of the transition section in step 1, and repeat steps 1 to 5. Step 6: Based on the axial width and flow dimensions of the transition section determined in Step 1, and in conjunction with the Bezier curve, construct the inner and outer flow profiles of the meridional channel of the turbine transition section; Step 7: Based on the inner and outer flow profiles of the meridional channel of the turbine transition section constructed in Step 6, calculate the flow area at different positions of the transition section to obtain the flow area relationship curve of the turbine transition section. Step 8: Using the flow area relationship curve of the turbine transition section obtained in Step 7, determine whether there is a sudden increase or decrease in the flow area in the curve. If so, adjust the control points of the Bezier curves of the inner and outer flow profiles of the meridional channel of the turbine transition section to adjust the flow area relationship curve of the turbine transition section until the flow area relationship curve of the turbine transition section is in a state of gradual increase.

2. The turbine transition section meridional flow channel profile design method as described in claim 1, characterized in that: In step 1, based on the maximum permissible axial width L of the turbine transition section z,max Determine the axial width L of the turbine transition section z According to the radius R of the outlet flow root of the upstream component of the gas turbine turbine. h,in Top radius R t,in Dimensions, downstream component inlet flow root radius R h,out Top radius R t,out Determine the turbine transition section flow path dimensions based on dimensional requirements, including the inlet root radius R. h,in Inlet top radius R t,in Imported area A in The root radius of the outlet is R. h,out The top radius of the outlet is R. t,out Export area A out Given the total pressure at the inlet of the transition section Imported static pressure p in Import flow G in .

3. The turbine transition section meridional flow channel profile design method as described in claim 2, characterized in that: In step 2, the dimensionless parameters include the transition section diffuser ratio k, the equivalent expansion angle α, the inlet hub ratio v, and the relative outlet radius. and relative axial length The aforementioned dimensionless parameters are calculated using the axial width of the transition section and the flow dimensions determined in step 2, as shown in equations (1) to (5):

4. The turbine transition section meridional flow channel profile design method as described in claim 3, characterized in that: In step 3, the rationality judgment condition includes: the transition section diffusion ratio k ≥ 1.

5. The turbine transition section meridional flow channel profile design method as described in claim 4, characterized in that: In step 4, the static pressure coefficient C of the transition section P We obtain the following from equation (6): Where, p in For imported static pressure, p out For the outlet static pressure, This is the total pressure of the import.

6. The turbine transition section meridional flow channel profile design method as described in claim 5, characterized in that: In step 5, when the static pressure coefficient C of the transition section P If the design requirements are not met, the constructed transition section model can be adjusted by increasing or decreasing the axial width of the transition section.

7. The turbine transition section meridional flow channel profile design method as described in claim 6, characterized in that: In step 6, the axial width L of the turbine transition section determined in step 1 is... z , Inlet root radius R h,in Inlet top radius R t,in , Exit root radius R h,out , Exit top radius R t,out The inner and outer flow profiles of the meridional channel in the turbine transition section are constructed using Bézier curves, where the Bézier curves are shown in equation (7): In the formula, P(t) represents the coordinates of any point on the Bézier curve, n represents the order of the Bézier curve, and i represents the current order, i = 0, 1, 2, ..., n; p i Let Bi,n(t) be the position vector of each vertex; Bi,n(t) is the Bernstein basis function. Where i = 0, 1, 2, ..., n, t is the curve parameter variable, 0 ≤ t ≤ 1.

8. The turbine transition section meridional flow channel profile design method as described in claim 7, characterized in that: In step 7, the method for obtaining the flow area relationship curve of the turbine transition section includes: calculating the flow centerline of the turbine transition section based on the inner and outer flow profiles of the meridional channel obtained in step 6, i.e., the curve formed by points equidistant from the inner and outer flow profiles of the meridional channel along the airflow direction; arranging 20-40 flow area measurement points i at equal intervals along the flow centerline of the turbine transition section along the airflow direction, and calculating the flow area A of the turbine transition section at each measurement point. i Plot the curve L, where the horizontal axis represents the length of the flow area measurement point at the centerline of the turbine transition section from the starting point to the horizontal axis. i The vertical axis represents the flow area A of the turbine transition section at the measurement point. i Relationship curve.

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