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CN-121997839-A - Low conductance free counter-rotating gas turbine and method of designing the same

CN121997839ACN 121997839 ACN121997839 ACN 121997839ACN-121997839-A

Abstract

The invention discloses a pneumatic design method of a low-conductivity-free contra-rotating gas turbine, which is characterized in that through multi-wheel iteration of three parts of a gas compressor, a combustion chamber and a turbine and the overall performance of AN engine, the value ranges and selection principles of parameters such as a high-low pressure turbine power ratio, a high-low pressure rotating speed ratio, a high-pressure turbine outlet air flow angle, AN AN 2 value and the like are given, so that the high-pressure turbine outlet air flow provides enough pre-rotation for a low-pressure turbine movable vane, the pneumatic performance of the turbine is improved, the modeling difficulty of the high-low pressure turbine movable vane and the performance matching and debugging difficulty of the high-low pressure rotor are reduced, the engineering practicability of the pneumatic design of the low-conductivity-free contra-rotating gas turbine and a downstream integrated transition section is ensured, the overall performance requirement of the engine and the functional matching requirement of the high-low pressure rotor are met, and the pneumatic design method is suitable for wide popularization and application. The invention also discloses the low-conductance-free counter-rotating gas turbine adopting the pneumatic design method of the low-conductance-free counter-rotating gas turbine.

Inventors

  • ZHANG CUNYUAN
  • LI WEI
  • ZENG FEI
  • QU BIN
  • SONG YOUFU

Assignees

  • 中国航发湖南动力机械研究所

Dates

Publication Date
20260508
Application Date
20260306

Claims (10)

  1. 1. A method of pneumatically designing a low conductance free counter-rotating gas turbine comprising the steps of: S1, determining a high-low pressure turbine power ratio and a value range of a high-low pressure turbine rotating speed ratio through multi-wheel iteration of three parts of a compressor, a combustion chamber and a turbine and the overall performance of an engine; S2, determining a value range of an outlet airflow angle of the high-pressure turbine based on the pre-rotation requirement of the low-pressure turbine movable blades on the outlet airflow of the high-pressure turbine; S3, adjusting and determining a target value of an influence parameter of the outlet air flow angle of the high-pressure turbine based on a calculation formula of the outlet air flow angle of the high-pressure turbine; s4, determining a selection principle of AN AN 2 value of the high-low pressure turbine based on the temperature resistance of the turbine component material and the relative total temperature of the inlet of the turbine movable blade; s5, determining blade profiles of a high-pressure turbine guide blade, a high-pressure turbine movable blade and a low-pressure turbine movable blade; and S6, carrying out numerical simulation, obtaining the total expansion ratio and efficiency of the low-conductance-free counter-rotating gas turbine in the design point state, and comparing and verifying with the design requirement.
  2. 2. The low conductance-free counter-rotating gas turbine aerodynamic design method of claim 1, wherein step S3 specifically comprises the steps of: based on a gas flow calculation formula, a calculation formula of an outlet gas flow angle of the high-pressure turbine is obtained through conversion, wherein the gas flow calculation formula is as follows: ; Wherein, therein In order to be a flow rate, For the dense flow coefficient of the liquid crystal, As the total pressure of the liquid is to be taken, For the total temperature to be the same, As a flow coefficient of the water, the water is mixed with water, Is the cross-sectional area of the cross-section, Is the air flow angle; The calculation formula of the high-pressure turbine outlet airflow angle is as follows: ; Wherein, the For the high pressure turbine outlet gas flow angle, For the high pressure turbine outlet flow function value, For the high pressure turbine outlet flow coefficient, The annular area of the high pressure turbine outlet; Analyzing a calculation formula of the high-pressure turbine outlet airflow angle, determining a high-pressure turbine expansion ratio and high-pressure turbine reaction force as influence parameters, keeping other parameters unchanged, adjusting the high-pressure turbine expansion ratio, determining the high-pressure turbine expansion ratio at the moment as a target value when the high-pressure turbine outlet airflow angle reaches the maximum value, selecting the high-pressure turbine expansion ratio as the target value, adjusting the high-pressure turbine reaction force until the high-pressure turbine outlet airflow angle is within a value range, and determining the high-pressure turbine reaction force at the moment as the target value.
  3. 3. The method for aerodynamic design of a low conductance-free counter-rotating gas turbine according to claim 1, wherein in step S1, the high-low pressure turbine power ratio is in the range of 1.8-3.
  4. 4. The method for aerodynamic design of a low conductance-free counter-rotating gas turbine according to claim 1, wherein in step S1, the ratio of high-low pressure turbine rotation speed is in the range of 1.2-1.7.
  5. 5. The method for aerodynamic design of a low conductance-free counter-rotating gas turbine according to claim 1, wherein in step S2, the high pressure turbine outlet gas flow angle has a value in the range of 30 ° -45 °.
  6. 6. The method for aerodynamic design of a low-conductance-free counter-rotating gas turbine according to any of claims 1-5, wherein in step S4, the selection criteria of the value of the high-low pressure turbine AN 2 are: When the relative total temperature of the inlet of the movable blade of the high-pressure turbine is 1550K, the AN 2 of the high-pressure turbine is smaller than 28; When the low pressure turbine bucket inlet relative total temperature is 1280K, the low pressure turbine AN 2 is less than 30.
  7. 7. The aerodynamic design method of a low conductance-free counter-rotating gas turbine of any one of claims 1-5, wherein in step S5, the high pressure turbine vane is front-edge-stacked with three basic vane profile sections of root, middle and tip, the high pressure turbine vane profile lift coefficient is 0.72-0.96, and the high pressure turbine vane profile load is of post-loading type.
  8. 8. The aerodynamic design method of a low-conductance-free counter-rotating gas turbine according to any one of claims 1 to 5, wherein in step S5, the high-pressure turbine rotor blade and the low-pressure turbine rotor blade are each formed by stacking the center of gravity by using three basic blade profile sections of root, middle and tip, wherein the lift coefficient of the high-pressure turbine rotor blade profile is 0.65-0.98, the load of the high-pressure turbine rotor blade profile is uniform loading type, the lift coefficient of the low-pressure turbine rotor blade profile is 0.62-0.95, and the load of the low-pressure turbine rotor blade profile is post-loading type.
  9. 9. The method for aerodynamic design of a low conductance free counter-rotating gas turbine according to any of claims 1-5, wherein the turbine runner is of equal pitch design and the low pressure turbine outlet downstream runner is of S-bend design.
  10. 10. A no-low conductance counter-rotating gas turbine employing the no-low conductance counter-rotating gas turbine aerodynamic design method of any one of claims 1-9.

Description

Low conductance free counter-rotating gas turbine and method of designing the same Technical Field The invention relates to the technical field of rotary impeller design, in particular to a pneumatic design method of a low-conductance-free counter-rotating gas turbine. In addition, the invention also relates to the low-conductance-free counter-rotating gas turbine adopting the pneumatic design method of the low-conductance-free counter-rotating gas turbine. Background With the development of society and the advancement of scientific technology, aircraft also put higher and higher requirements on the performance of aviation gas turbine shaft/propeller engines, such as higher power-to-weight ratio, lower fuel consumption rate, higher reliability, etc., while in order to achieve the goals of high power-to-weight ratio, low fuel consumption, high reliability, etc., the gas turbines in advanced aviation gas turbine shaft/propeller engines mostly adopt 1+1/2 counter-rotating turbine designs. The 1+1/2 counter-rotating turbine design refers to a turbine layout in which the rotation directions of the gas high-pressure turbine rotor and the gas low-pressure turbine rotor are opposite, no low-pressure turbine guide vanes exist, and the downstream low-pressure turbine movable blades fully utilize pre-rotation work generated by the upstream high-pressure turbine outlet airflow. In the turbine layout, the low-pressure turbine guide vanes are omitted, so that the axial length and weight of the low-pressure turbine can be obviously reduced, the power-weight ratio of the engine is improved, and meanwhile, the counter-rotating rotors can mutually offset the gyroscopic moment of the unidirectional rotating rotors acting on the aircraft, so that the maneuverability and operability of the aircraft are improved, and the high-performance requirement of the aviation gas turbine shaft/propeller engine is met. For example, the Chinese patent No. CN112528474B discloses a one-dimensional pneumatic design method for a guide vane-free counter-rotating turbine, and belongs to the technical field of pneumatic design of guide vane-free counter-rotating turbines. According to the design characteristics of the guide vane-free counter-rotating turbine, the method for selecting the key parameters of the speed triangle of the guide vane-free counter-rotating turbine or the reasonable value range is provided, and further the one-dimensional pneumatic design method of the guide vane-free counter-rotating turbine is discussed and developed. The design method can rapidly and accurately evaluate the aerodynamic performance of the guide vane-free counter-rotating turbine, and realizes the optimal design of the counter-rotating turbine by reasonably selecting design parameters. However, the design method mainly considers that the turbine is pneumatically designed as a single component, namely, the speed triangle of the 1+1/2 counter-rotating turbine starts, so that the bending angle of the high-pressure turbine movable blade profile is small, the installation angle and the outlet air flow angle are large, the modeling difficulty of the high-pressure turbine movable blade and the low-pressure turbine movable blade is large, meanwhile, the high-pressure turbine movable blade grid channels and the low-pressure turbine movable blade grid channels are in supercritical flow states, the turbine reserve power is low, and the performance matching and debugging of the high-pressure rotor and the low-pressure rotor of the subsequent engine are difficult. Disclosure of Invention The invention provides a low-conductivity-free contra-rotating gas turbine and a design method thereof, which are used for solving the technical problems of high and low pressure turbine movable vane blade modeling difficulty and difficult matching and debugging of high and low pressure rotor performance of an engine of the existing 1+1/2 contra-rotating turbine. According to one aspect of the invention, a pneumatic design method of a low-conductance-free counter-rotating gas turbine is provided, wherein S1, through multi-round iteration of the overall performance of a compressor, a combustion chamber and a turbine and AN engine, a high-pressure turbine power ratio and a high-pressure turbine rotation speed ratio are determined, S2, a high-pressure turbine outlet airflow angle value range is determined based on pre-rotation requirements of the low-pressure turbine rotor blade on a high-pressure turbine outlet airflow, S3, a target value of AN influence parameter of the high-pressure turbine outlet airflow angle is adjusted and determined based on a calculation formula of the high-pressure turbine outlet airflow angle, S4, a selection principle of a high-pressure turbine AN 2 is determined based on the temperature resistance of turbine component materials and the total temperature of turbine rotor blade inlets, S5, the leaf shapes of the high-pressure turbine guide blade, the high-pressur