阅读说明：本技术 一种变几何涡轮一维气动设计方法 (Variable geometry turbine one-dimensional pneumatic design method ) 是由 高杰 霍东晨 李彦静 赵天笑 闫睿 于 2021-07-08 设计创作，主要内容包括：本发明的目的在于提供一种变几何涡轮一维气动设计方法,利用常见的平均中径法,完成常规涡轮的气动设计；进而利用流量与可转导叶转角关联式估算出可转导叶转角范围,通过一维总静流函数法并结合可调导叶间隙泄漏损失模型,计算出变几何涡轮在各个转角下效率,最后将各转角下效率平均得出变几何涡轮平均效率；若变几何涡轮平均效率满足设计要求,则变几何涡轮一维设计完成；若不符合调整变几何涡轮一维气动部分设计参数,直至变几何涡轮性能满足设计要求。本发明可综合判断变几何涡轮各工况效率,从而得到一种各工况下均具有较高效率的变几何涡轮气动设计方案,从而提高变几何涡轮变工况性能；此外,本发明也可明显提高变几何涡轮一维设计速度。(The invention aims to provide a variable geometry turbine one-dimensional pneumatic design method, which utilizes a common average pitch diameter method to complete the pneumatic design of a conventional turbine; then, estimating a rotatable guide vane rotation angle range by utilizing a flow and rotatable guide vane rotation angle correlation, calculating the efficiency of the variable geometry turbine at each rotation angle by a one-dimensional total static flow function method and combining an adjustable guide vane clearance leakage loss model, and finally averaging the efficiency at each rotation angle to obtain the average efficiency of the variable geometry turbine; if the average efficiency of the variable geometry turbine meets the design requirement, completing the one-dimensional design of the variable geometry turbine; if the design parameters of the one-dimensional pneumatic part of the variable geometry turbine are not met, the performance of the variable geometry turbine meets the design requirements. The method can comprehensively judge the efficiency of each working condition of the variable geometry turbine, thereby obtaining a variable geometry turbine pneumatic design scheme with higher efficiency under each working condition, and further improving the variable working condition performance of the variable geometry turbine; in addition, the invention can also obviously improve the one-dimensional design speed of the variable geometry turbine.)

1. A variable geometry turbine one-dimensional pneumatic design method is characterized by comprising the following steps:

(1) giving initial geometric parameters and pneumatic parameters, wherein the initial geometric parameters and the pneumatic parameters comprise a dynamic and static blade aspect ratio, a maximum thickness ratio chord length, a tail edge thickness ratio throat width, rim work, total inlet temperature and total pressure, a guide vane inlet airflow angle, a load coefficient, a flow coefficient, a reaction degree, an axial speed ratio and an inlet-outlet diameter ratio;

(2) solving the hub ratio and the blade height of the movable and fixed blades according to the one-dimensional geometric parameters of the turbine, and analyzing the change of turbine stage reaction degree, load coefficient, flow coefficient, axial speed ratio and airflow angle after the guide blade rotates by a one-dimensional total static flow function method;

(3) after the guide vane rotates, the pneumatic parameters and the geometric parameters are input into a loss model, and the speed loss coefficients of the moving and static vanes after various rotation angles are changed are calculated, so that the turbine efficiency of the variable-geometry turbine under each rotation angle can be obtained.

2. The one-dimensional aerodynamic design method of the variable geometry turbine as claimed in claim 1, wherein:

(a) correlation between rotating angle of guide vane and variable geometry turbine flowPre-estimating the rotation angle of the rotatable guide vane;

(b) dividing the rotating angle of the rotatable guide vane into n parts, and respectively calculating the working condition efficiency of each rotating angle by utilizing a one-dimensional total static flow function method and integrating an adjustable guide vane gap leakage loss model;

(c) calculating the average efficiency of the variable geometry turbine at different turning angles based on step (b);

(d) and (c) if the performance index obtained in the step (c) does not meet the preset design target, modifying one-dimensional design parameters in a conventional turbine one-dimensional design cycle, and cycling the steps (a) - (c) until the aerodynamic performance of the turbine reaches the preset design target.

3. The one-dimensional aerodynamic design method of the variable geometry turbine as claimed in claim 1, wherein:

for a variable geometry turbine, the derivation process of the one-dimensional total static flow function method is as follows:

the one-dimensional total static flow function method respectively comprises guide vane flow m₁And bucket flow m₂Total static expansion ratio along guide vaneThe change rule is that the turbine stage passage is regarded as a one-dimensional spray pipe, and the total pressure P at the inlet of the guide vane₀ ^*Total temperature T₀ ^*Static pressure P at outlet of rotor blade₁The guide vane flow is defined as:

m₁＝ρ₁c₁A₁sinα₁

where ρ is₁Is the gas density in the guide vane passage, c₁Is the vane outlet absolute velocity, α₁Is the guide vane absolute outlet flow angle;

according to the ideal gas state equation P₀ ^*＝ρ₀ ^*R_gT₀ ^*And variable processesAnd T₀ ^*＝T₁ ^*Get the formula

By combining the above formulas, the method can be obtained

The rule that the flow of the guide vane changes along with the total static expansion ratio of the guide vane can be obtained;

establishing guide vane multivariable process index and speed loss coefficient through the following formulaThe relationship of (1):

obtaining lambda according to a continuous equation and an energy conservation equation_c1Static temperature T of inlet of mixing movable blade₁：

T^* ₁＝T^* ₀

T₁＝T^* ₁τ(λ_c1)

According to bucket inlet continuity equation, from_c1To obtain lambda_ω1And according to λ_ω1Obtaining the relative total temperature and the relative total pressure of the movable blade inlet:

P^* _ω1＝P₁/π(λ_ω1)

T^* _ω1＝T₁/τ(λ_ω1)

and the speed factor lambda of the outlet of the guide vane can be obtained according to the formula and the pneumatic function_c1Static temperature T₁For the movable blade, the change rule of the movable blade flow rate along with the total static expansion ratio of the guide blade, the speed loss coefficient and the outlet relative airflow angle is deduced by the following formulas under a relative coordinate system:

m₂＝ρ₂ω₂A₂sinβ₂

according to the ideal gas state equation and P₁＝ρ₁R_gT₁And variable processesCan obtain the product

The change rule of the movable blade flow along with the total static expansion ratio of the turbine guide vane is obtained by combining the formulas:

wherein beta is₂Other parameters can be obtained by known parameters for the geometric gas outlet angle of the movable blade, so that the change rule of the flow of the movable blade along with the total static expansion ratio of the guide blade outlet can be obtained. The intersection point of the flow of the movable blades and the flow of the guide vanes is a turbine stage working point.

4. The one-dimensional aerodynamic design method of the variable geometry turbine as claimed in claim 1, wherein: for the variable geometry turbine, the derivation process of the correlation between the guide vane corner change and the flow of the variable geometry turbine is as follows:

after the guide vane is geometrically adjusted, the geometric gas outlet angle of the guide vane outlet is directly changed, and the geometric gas outlet angle alpha of the guide vane after rotation is obtained through the geometric relation_1zIs alpha₁And the sum of the rotation angle seita, wherein seita is positive value and indicates that the guide vane is opened greatly, and seita is negative value, and the absolute outlet airflow angle of the guide vane after rotation and the relative outlet airflow angle of the movable blade under the condition of neglecting the drop angle are shown as the following formula:

α_1z＝α₁+seita

β_2z＝β₂

for the variable geometry turbine, the correction formula of the variable geometry turbine adjustable guide vane gap leakage loss model is as follows:

Y_TI＝K_z(Y_gap+Y_mix)

wherein Y is_TIKz is a rotating shaft correction factor, Y, for a gap leakage loss_gapFor internal losses in the gap, Y_mixLeakage flow and main flow mixing loss;

the rotation axis correction coefficient Kz is:

5. the one-dimensional aerodynamic design method of the variable geometry turbine as claimed in claim 1, wherein: the outlet flow angle of the guide vane of the variable geometry turbine ranges from 15 degrees to 25 degrees, the optimal reaction degree area of the variable geometry turbine is basically between 0.25 and 0.6, the flow coefficient is between 0.3 and 0.5, and the axial speed ratio is selected to range from 1 to 1.4.

Technical Field

The invention relates to a design method of a gas turbine, in particular to a design method of a turbine.

Background

The pneumatic design work of the turbine of the gas turbine is a process of gradually designing and optimizing from a low dimension to a high dimension, a low dimension design result is used as an initial value and a basis of the high dimension design, in order to complete the pneumatic design work of the variable geometry turbine, firstly, the problem to be solved is how to select the pneumatic design parameters suitable for the variable geometry turbine, the design and parameter selection work needs to be carried out in a one-dimensional space, the one-dimensional loss model of the turbine is used as a core and a basis of one-dimensional calculation, the accuracy of the one-dimensional loss model directly determines whether the one-dimensional design is successful, and the leakage loss model of the adjustable guide vane gap is corrected, so that the variable geometry turbine loss model suitable for and accurately estimated is obtained.

The research on the one-dimensional parameter selection rule of the conventional turbine usually adopts an average pitch diameter method, one-dimensional calculation is set on the average pitch diameter of an inlet and an outlet of a blade row, the blade row is solved row by row through a basic aerodynamic relational expression according to known geometric parameters and boundary conditions, and the relations of turbine efficiency and turbine aerodynamic parameters such as load coefficient, flow coefficient, reaction degree, axial speed ratio and geometric parameters such as the aspect ratio of guide vanes and movable vanes, the consistency of blade grids and the like are established by combining a loss model, so that the correlation between the turbine efficiency and the parameters is analyzed, and a relational graph such as Smith and the like is drawn to visually find the optimal selection in the turbine design parameters. The variable geometry turbine is greatly different from a conventional turbine, the turbine efficiency under the design working condition is not enough to describe the performance of the variable geometry turbine, the variable geometry turbine must ensure that the non-design working condition still keeps higher turbine efficiency besides the conventional design working condition, therefore, different from the conventional turbine one-dimensional parameter selection rule research, the variable geometry turbine one-dimensional parameter selection rule research must comprehensively consider the turbine efficiency under different corners, namely, after the turbine pneumatic design under the design working condition is completed through one-dimensional parameters, the turbine efficiency under different corners is evaluated by using a one-dimensional performance prediction method considering an adjustable guide vane gap leakage loss model, the turbine efficiency average value under each corner working condition is obtained, and the region with the highest average efficiency is the optimal one-dimensional parameter region.

In order to explore a variable geometry turbine one-dimensional parameter selection rule, firstly, the problem to be solved is that the change rule of turbine pneumatic design parameters such as reaction degree and the like after a variable geometry turbine guide vane rotates is solved, so that the one-dimensional parameters and the corners under different working conditions are linked, turbine efficiency values under different corners are finally obtained, the selection range of the variable geometry turbine one-dimensional parameters is determined by analyzing the design parameters and the average efficiency under different corners, and then the variable geometry turbine one-dimensional pneumatic design method is discussed and developed.

Disclosure of Invention

The invention aims to provide a one-dimensional pneumatic design method of a variable geometry turbine, which can enable the average efficiency of all working conditions of the variable geometry turbine to reach a higher level.

The purpose of the invention is realized as follows:

the invention relates to a variable geometry turbine one-dimensional pneumatic design method, which is characterized by comprising the following steps:

(1) giving initial geometric parameters and pneumatic parameters, wherein the initial geometric parameters and the pneumatic parameters comprise a dynamic and static blade aspect ratio, a maximum thickness ratio chord length, a tail edge thickness ratio throat width, rim work, total inlet temperature and total pressure, a guide vane inlet airflow angle, a load coefficient, a flow coefficient, a reaction degree, an axial speed ratio and an inlet-outlet diameter ratio;

(2) solving the hub ratio and the blade height of the movable and fixed blades according to the one-dimensional geometric parameters of the turbine, and analyzing the change of turbine stage reaction degree, load coefficient, flow coefficient, axial speed ratio and airflow angle after the guide blade rotates by a one-dimensional total static flow function method;

(3) after the guide vane rotates, the pneumatic parameters and the geometric parameters are input into a loss model, and the speed loss coefficients of the moving and static vanes after various rotation angles are changed are calculated, so that the turbine efficiency of the variable-geometry turbine under each rotation angle can be obtained.

The present invention may further comprise:

1. (a) flow correlation with variable geometry turbine using rotatable vane turn anglePre-estimating the rotation angle of the rotatable guide vane;

(b) dividing the rotating angle of the rotatable guide vane into n parts, and respectively calculating the working condition efficiency of each rotating angle by utilizing a one-dimensional total static flow function method and integrating an adjustable guide vane gap leakage loss model;

(c) calculating the average efficiency of the variable geometry turbine at different turning angles based on step (b);

(d) and (c) if the performance index obtained in the step (c) does not meet the preset design target, modifying one-dimensional design parameters in a conventional turbine one-dimensional design cycle, and cycling the steps (a) - (c) until the aerodynamic performance of the turbine reaches the preset design target.

2. For a variable geometry turbine, the derivation process of the one-dimensional total static flow function method is as follows:

the one-dimensional total static flow function method respectively comprises guide vane flow m₁And bucket flow m₂Total static expansion ratio along guide vaneThe change rule is that the turbine stage passage is regarded as a one-dimensional spray pipe, and the total pressure P at the inlet of the guide vane₀ ^*Total temperature T₀ ^*Static pressure P at outlet of rotor blade₁The guide vane flow is defined as:

m₁＝ρ₁c₁A₁ sinα₁

where ρ is₁Is the gas density in the guide vane passage, c₁Is the vane outlet absolute velocity, α₁Is the guide vane absolute outlet flow angle;

according to the ideal gas state equation P₀ ^*＝ρ₀ ^*R_gT₀ ^*And variable processesAnd T₀ ^*＝T₁ ^*Get the formula

By combining the above formulas, the method can be obtained

The rule that the flow of the guide vane changes along with the total static expansion ratio of the guide vane can be obtained;

establishing guide vane multivariable process index and speed loss coefficient through the following formulaThe relationship of (1):

obtaining lambda according to a continuous equation and an energy conservation equation_c1Static temperature T of inlet of mixing movable blade₁：

T^* ₁＝T^* ₀

T₁＝T^* ₁τ(λ_c1)

According to bucket inlet continuity equation, from_c1To obtain lambda_ω1And according to λ_ω1Obtaining the relative total temperature and the relative total pressure of the movable blade inlet:

P^* _ω1＝P₁/π(λ_ω1)

T^* _ω1＝T₁/τ(λ_ω1)

and the outlet speed factor of the guide vane can be obtained according to the formula and the pneumatic functionStatic temperature T₁For the movable blade, the change rule of the movable blade flow rate along with the total static expansion ratio of the guide blade, the speed loss coefficient and the outlet relative airflow angle is deduced by the following formulas under a relative coordinate system:

m₂＝ρ₂ω₂A₂ sinβ₂

according to the ideal gas state equation and P₁＝ρ₁R_gT₁And variable processesCan obtain the product

The change rule of the movable blade flow along with the total static expansion ratio of the turbine guide vane is obtained by combining the formulas:

wherein beta is₂For the geometric gas outlet angle of the movable blade, other parameters can be obtained by known parameters, so that the geometric gas outlet angle of the movable blade can be obtainedThe flow of the movable blades changes along with the total static expansion ratio of the guide vane outlet. The intersection point of the flow of the movable blades and the flow of the guide vanes is a turbine stage working point.

3. For the variable geometry turbine, the derivation process of the correlation between the guide vane corner change and the flow of the variable geometry turbine is as follows:

after the guide vane is geometrically adjusted, the geometric gas outlet angle of the guide vane outlet is directly changed, and the geometric gas outlet angle alpha of the guide vane after rotation is obtained through the geometric relation_1zIs alpha₁And the sum of the rotation angle seita, wherein seita is positive value and indicates that the guide vane is opened greatly, and seita is negative value, and the absolute outlet airflow angle of the guide vane after rotation and the relative outlet airflow angle of the movable blade under the condition of neglecting the drop angle are shown as the following formula:

α_1z＝α₁+seita

β_2z＝β₂

for the variable geometry turbine, the correction formula of the variable geometry turbine adjustable guide vane gap leakage loss model is as follows:

Y_TI＝K_z(Y_gap+Y_mix)

wherein Y is_TIKz is a rotating shaft correction factor, Y, for a gap leakage loss_gapFor internal losses in the gap, Y_mixLeakage flow and main flow mixing loss;

the rotation axis correction coefficient Kz is:

4. the outlet flow angle of the guide vane of the variable geometry turbine ranges from 15 degrees to 25 degrees, the optimal reaction degree area of the variable geometry turbine is basically between 0.25 and 0.6, the flow coefficient is between 0.3 and 0.5, and the axial speed ratio is selected to range from 1 to 1.4.

The invention has the advantages that: according to the design characteristics of the variable geometry turbine, the flow, the airflow angle and each aerodynamic parameter of working points of the guide vane and the movable vane at different rotation angles can be obtained through a bisection method by keeping the total pressure of the inlet of the guide vane, the total temperature and the static pressure of the outlet of the movable vane before and after the guide vane rotates unchanged and only changing the airflow angle of the outlet of the guide vane in a one-dimensional total static flow function method. The design method can conveniently and accurately evaluate the pneumatic performance of the variable geometry turbine under different rotation angles, and provides a method for selecting the key parameters of the speed triangle of the variable geometry turbine or a one-dimensional parameter selection rule, so as to discuss and develop the one-dimensional pneumatic design method of the variable geometry turbine.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a schematic view of a one-dimensional pipe flow model of a blade row;

FIG. 3 is a schematic view of rotatable vane and bucket flow matching;

FIG. 4 is a schematic view of rotatable vane rotation;

FIG. 5 shows Kz at different axial positions and axial diameters after fitting;

FIG. 6 is a graph showing the variation of the average efficiency and the design efficiency with the reaction degree under different rotation angle conditions.

Detailed Description

The invention will now be described in more detail by way of example with reference to the accompanying drawings in which:

with reference to fig. 1-6, the invention provides a one-dimensional pneumatic design method for a variable geometry turbine, in the method, a one-dimensional performance prediction method, a one-dimensional total static flow function method and a geometric parameter solving efficiency calculation formula of an adjustable guide vane clearance leakage loss model are comprehensively considered, and a variable geometry turbine one-dimensional parameter selection rule program is compiled, and the method specifically comprises the following steps:

1. initial geometric parameters and pneumatic parameters are given, and the parameters comprise the dynamic and static blade aspect ratio, the maximum thickness ratio chord length, the tail edge thickness ratio throat width, the rim work, the inlet total temperature and total pressure, the guide vane inlet airflow angle, the load coefficient, the flow coefficient, the reaction degree, the axial speed ratio, the inlet-outlet diameter ratio and the like.

2. According to the one-dimensional geometric parameters of the turbine, the geometric parameters such as the hub ratio, the blade height and the like of the movable and fixed blades are solved, and the change of the turbine stage reaction degree, the load coefficient, the flow coefficient, the axial speed ratio and the airflow angle after the guide blade is rotated is analyzed through a one-dimensional total static flow function method.

3. After the guide vane rotates, the pneumatic parameters and the geometric parameters are input into an adjustable guide vane gap leakage loss model, and the speed loss coefficients of the moving and static vanes after various corners are changed are calculated, so that the turbine efficiency of the variable geometry turbine under each corner can be obtained.

The method also comprises the following steps after the conventional turbine one-dimensional design cycle:

(1) and (4) according to the actual flow change requirement, and by utilizing a formula (16), obtaining the rotating angle change range of the rotatable guide vane of the variable geometry turbine.

(2) The rotating angle of the rotatable guide vane is divided into a plurality of rotating angle working conditions, and the working condition efficiency of each rotating angle of the variable geometry turbine after the rotating angle of the rotatable guide vane of the variable geometry turbine is changed is obtained by utilizing a one-dimensional total static flow function method.

(3) And (3) carrying out weighted average on the working condition efficiency of each corner obtained in the step (2) to obtain the average efficiency of the variable geometry turbine.

(4) And (4) if the performance index obtained in the step (3) does not meet the preset design target, repeating the steps (1) to (3) until the performance index obtained in the step (3) meets the preset design target.

The one-dimensional total static flow function method respectively comprises guide vane flow m₁And bucket flow m₂Total static expansion ratio along guide vaneThe change rule of (2). Preferably, in the method, the turbine stage passages may be considered as one-dimensional nozzles, as in fig. 2, the total vane inlet pressure P₀ ^*Total temperature T₀ ^*Static pressure P at outlet of rotor blade₁. The vane flow may be defined as:

m₁＝ρ₁c₁A₁sinα₁ (1)

where ρ is₁For gas in the guide vane passageBulk density, c₁Is the vane outlet absolute velocity, α₁Is the guide vane absolute outlet flow angle.

According to the ideal gas state equation P₀ ^*＝ρ₀ ^*R_gT₀ ^*And variable processesAnd T₀ ^*＝T₁ ^*Available formula

By combining the above formulas, the method can be obtained

And the rule that the flow of the guide vane changes along with the total static expansion ratio of the guide vane can be obtained.

Establishing guide vane multi-variable process index and speed loss coefficient through formula (5)In relation to (2)

According to the continuous equation and the energy conservation equation, the lambda can be obtained_c1Static temperature T of inlet of mixing movable blade₁：

From the bucket inlet continuity equation, may be given by_c1To obtain lambda_ω1And according to λ_ω1The relative total temperature and the relative total pressure of the inlet of the movable blade can be obtained:

and the outlet speed factor of the guide vane can be obtained according to the formula and the pneumatic functionStatic temperature T₁And the like. For the movable blade, the change rule of the movable blade flow along with the total static expansion ratio of the guide blade, the speed loss coefficient and the outlet relative airflow angle can be derived by the following formulas under a relative coordinate system:

m₂＝ρ₂ω₂A₂ sinβ₂ (10)

similar equation of state based on ideal gas and P₁＝ρ₁R_gT₁And variable processesCan obtain the product

The rule of the change of the movable blade flow along with the total static expansion ratio of the turbine guide blade can be obtained by combining the above formulas, namely the formula (14)

Wherein beta is₂Other parameters can be obtained by known parameters for the geometric gas outlet angle of the movable blade, so that the change rule of the flow of the movable blade along with the total static expansion ratio of the guide blade outlet can be obtained.

As shown in fig. 3, the intersection point of the blade flow and the guide vane flow is the turbine stage operating point. The invention can rapidly determine the working point of the turbine stage by applying the one-dimensional total static flow function method, and the method can rapidly determine the change rule of the flow, the reaction degree, the equal starting parameters under the working condition of each corner after the guide vane rotates.

FIG. 4 is a schematic view of the rotation of the guide vane, and the geometric outlet angle of the guide vane outlet is directly changed after the guide vane is geometrically adjusted. The geometric gas outlet angle alpha of the rotary rear guide vane is easily obtained through simple geometric relationship_1zIs alpha₁And the sum of the rotation angle seita, wherein seita is positive value and indicates that the guide vane is opened greatly, and seita is negative value, and the absolute outlet airflow angle of the guide vane after rotation and the relative outlet airflow angle of the movable blade under the condition of neglecting the drop angle are shown as the following formula:

the guide vane rotates to greatly change the flow characteristic curve of the guide vane, and the flow characteristic curve of the movable vane also changes slightly due to the change of the pneumatic parameters such as outlet static pressure and the like after the guide vane rotates. The change of the flow is mainly determined by two factors, namely a guide vane outlet airflow angle and a guide vane total static expansion ratio, and the influence of the guide vane outlet airflow angle is far greater than the guide vane total static expansion ratio, so that the influence of the variable geometry turbine guide vane rotation angle change on the flow can be expressed by a formula (16).

And (4) according to the actual flow change requirement, and by utilizing a formula (16), obtaining the rotating angle change range of the rotatable guide vane of the variable geometry turbine.

Establishing a variable geometry turbine adjustable guide vane gap leakage loss model, wherein a correction formula is as follows:

Y_TI＝K_z(Y_gap+Y_mix) (17)

wherein Y is_TIKz is a rotating shaft correction factor, Y, for a gap leakage loss_gapFor internal losses in the gap, Y_mixThe loss is blended between the leakage flow and the main flow.

The position of the axis of rotation of the adjustable vane can be described as the dimensionless position of the camber line of the airfoil, and the diameter of the axis can be dimensionless as a ratio to the chord length. And (3) researching the leakage loss of the gaps of the adjustable guide vanes at different axial positions and axial diameters, fitting the leakage loss of the gaps of the adjustable guide vanes into a function of a dimensionless axial position x and a dimensionless axial diameter y by adopting two-dimensional polynomial fitting, and obtaining a correction coefficient Kz of the rotating shaft, such as the correction coefficient Kz of the leakage loss of the gaps of the adjustable guide vanes at different axial positions and axial diameters shown in FIG. 5.

Wherein p 00-0.8145, p 10-2.135, p 01-16.55, p 20-4.16, p 11-0.2775, p 02-81.45, p 30-2.36, p 21-30.58, p 12-37.67, p 03-142.9, p 31-28.77, p 22-17.22, p 13-20.86, and p 04-93.6.

The outlet flow angle of the guide vane of the variable geometry turbine ranges from 15 degrees to 25 degrees, the optimal reaction degree area of the variable geometry turbine is basically between 0.25 and 0.6, the flow coefficient is between 0.3 and 0.5, and the axial speed ratio is selected to range from 1 to 1.4.

And according to the requirement of adjusting the flow, predicting the required rotatable guide vane rotation angle by utilizing the correlation between the variable geometry turbine guide vane rotation angle change and the flow.

Given a reduced rotational speed, for example, a variable geometry turbineReduced flowThe rim work is 263.792(kW/(kg/s)), the aspect ratio of the movable and static blades is 1.5, the cascade consistency of the static blades is 1.1, the consistency of the movable blades is 1.7, the maximum thickness ratio chord of the static blades is 0.15, the maximum thickness ratio chord of the movable blades is 0.2, the thickness ratio of the tail edge of the static blade to the throat width is 0.12, the thickness ratio of the tail edge of the movable blade to the chord is 0.2, the height ratio of the gap of the static blade to the height of the blade is 1.8%, the height ratio of the gap of the movable blade to the height of the blade is 1%, the axial chord position of 60% is selected for the rotating shaft, and the axial diameter ratio chord position is 34%. Under the condition, the selection rules of the reaction degree, the axial speed ratio, the load coefficient and the flow coefficient under different corner working conditions are researched, and the boundary conditions under different corners are kept the same.

From fig. 6, it is a graph showing that the flow coefficient is 0.4, the average efficiency under different rotation angle working conditions and the design efficiency vary with the reaction degree under different load coefficients (HT), and overall, when the reaction degree is small, the average efficiency under each working condition is smaller than the efficiency under the design working condition, otherwise, the average efficiency under each working condition is greater than the efficiency under the design working condition, the efficiency decreases after increasing with the reaction degree, there is an optimal reaction degree, and the optimal reaction degree gradually increases with the increase of the load coefficient. Generally speaking, when the load factor is 1, the optimal reaction degree corresponding to the average efficiency is about 10% smaller than the optimal reaction degree under the design working condition, along with the increase of the load factor, the optimal reaction degree corresponding to the average efficiency is gradually closer to the optimal reaction degree under the design working condition, and the optimal reaction degree area of the variable geometry turbine is basically between 0.25 and 0.6.

The single-stage turbine designed by the invention can improve the pneumatic efficiency by 0.7 percent on the premise of keeping the flow of the turbine basically unchanged.

The invention can also be used for the high-efficiency aerodynamic design of the multistage variable-geometry turbine.