CN-121994495-A - Rotational flow state analysis method based on angular momentum transfer

CN121994495ACN 121994495 ACN121994495 ACN 121994495ACN-121994495-A

Abstract

The application belongs to the technical field of aeroengines, and particularly relates to a rotational flow state analysis method based on angular momentum transfer, which comprises the steps of obtaining structural parameters of a cyclone and a contraction channel, including the inner radius of a ring surface of an outlet section of a blade channel Annular outer radius of blade channel outlet section Annular inner radius of throat section Annular outer radius of throat section Blade angle θ, and throat section pitch angle Based on the conservation of mass equation and the conservation of angular momentum equation, the swirl state of the section of the blade channel outlet is taken as an initial value, and the swirl number S N2 of the section of the throat is calculated to obtain the deflection angle beta of the airflow. The cyclone flow control device integrates the influence of structural parameters of the cyclone and the contraction channel on the flow, characterizes the cyclone flow state at the outlet of the head, is closer to the top dead center of the flame root/the backflow zone, and can reveal more information affecting the combustion structure.

Inventors

CHU XIAOGANG
CHEN YALIN
ZHANG HONGDA
SHI LEI
ZHANG JUNFENG
ZHANG CHENGKAI
CHENG MING
WANG XINZHU
LIN HONGJUN
CHANG FENG

Assignees

中国航发沈阳发动机研究所

Dates

Publication Date: 20260508
Application Date: 20260210

Claims (7)

1. A method of rotational flow state analysis based on angular momentum transfer, comprising: obtaining structural parameters of the cyclone and the contraction passage, including the inner radius of the annulus of the outlet section of the vane passage Annular outer radius of blade channel outlet section Annular inner radius of throat section Annular outer radius of throat section Blade angle θ, and throat section pitch angle ; Based on the mass conservation equation and the angular momentum conservation equation, the swirl state of the section of the blade channel outlet is taken as an initial value, and the swirl number S N2 of the section of the throat is calculated to obtain the airflow deflection angle beta.
2. The rotational flow state analysis method based on angular momentum transfer according to claim 1, wherein the mass conservation equation is: ; For the axial velocity of the vane passage outlet cross section, Is the axial velocity of the throat section.
3. The rotational flow state analysis method based on angular momentum transfer according to claim 2, wherein the angular momentum conservation equation is: ; for tangential velocity of the blade channel outlet cross section, Is the tangential velocity of the throat section.
4. A method of analyzing a swirl state based on angular momentum transfer according to claim 3, wherein the formula of calculation of the swirl number S N2 of the throat section is: 。
5. A method of analyzing a rotational flow state based on angular momentum transfer according to claim 3, wherein the number of swirl flows in the cross section of the outlet of the passage The calculation formula of (2) is as follows: 。
6. the rotational flow state analysis method based on angular momentum transfer according to claim 3, wherein the throat section airflow deflection angle calculation formula is: 。
7. a method of analyzing rotational flow state based on angular momentum transfer according to claim 3 and based on simplifying assumptions including incompressible fluid, constant density ρ, two-dimensional velocity distribution, neglecting radial velocity considering only axial and tangential components, uniform velocity on the same cross section, and consistent deflection angle of air flow at the exit of the vane passage with vane angle.

Description

Rotational flow state analysis method based on angular momentum transfer Technical Field The application belongs to the technical field of aeroengines, and particularly relates to a rotational flow state analysis method based on angular momentum transfer. Background The combined structure of the cyclone (deflecting airflow by using fixed blades to make the airflow flow along the axial rotation) and the contraction channel is a well-developed and widely applied combustion tissue head structure in the technical field of main combustion chambers, and forms a backflow flame stabilizing structure in the main combustion area by the cyclone-contraction-expansion flow to form a flame root for stable combustion. Designers often use swirl numbersThis dimensionless parameter characterizes the swirl strength of the swirler vane passage outlet cross-section to guide the design of the swirler. However, the design of the constriction channel structure is often independently studied on the length and the constriction area ratio of the constriction section, and is relatively split with the design of the cyclone, so that the effective association is not formed. The method for predicting and analyzing the influence of the two structures on the flow is required to be provided, so that the working efficiency of the primary one-dimensional design of the head structure of the main combustion chamber is improved, and the iteration rounds are reduced. The traditional method for calculating the downstream swirl number of the head is to calculate and obtain the swirl number of the outlet section of the blade channel according to the structural parameters such as the angle, the inner diameter and the outer diameter of the blade of the cyclone. Only the influence of the structural parameters of the cyclone on the flow is reflected, only the cyclone state at the outlet of the cyclone can be represented, and the cyclone state is difficult to directly relate to combustion tissues, so that the cyclone can be only used as one of the influence factors for qualitative analysis. The cyclone number prediction method is accurate for the cyclone number prediction with a simple structure, but the more complex the follow-up flow structure of the cyclone is, the worse the prediction accuracy is. The traditional method of calculating the deflection angle of the airflow downstream of the head is to directly take the angle of the swirler vanes as the deflection angle of the airflow. Only the influence of the angle of the cyclone blade on the flow is reflected, and the reference value is limited. The prediction of the airflow deflection angle is inaccurate. Disclosure of Invention In order to solve the above problems, the present application provides a rotational flow state analysis method based on angular momentum transfer, including: obtaining structural parameters of the cyclone and the contraction passage, including the inner radius of the annulus of the outlet section of the vane passage Annular outer radius of blade channel outlet sectionAnnular inner radius of throat sectionAnnular outer radius of throat sectionBlade angle θ, and throat section pitch angle; Based on the mass conservation equation and the angular momentum conservation equation, the swirl state of the section of the blade channel outlet is taken as an initial value, and the swirl number S N2 of the section of the throat is calculated to obtain the airflow deflection angle beta. Preferably, the mass conservation equation is: ; For the axial velocity of the vane passage outlet cross section, Is the axial velocity of the throat section. Preferably, the angular momentum conservation equation is: ; for tangential velocity of the blade channel outlet cross section, Is the tangential velocity of the throat section. Preferably, the calculation formula of the swirl number S N2 of the throat section is as follows: 。 preferably, the number of swirl flow in the outlet cross section of the channel The calculation formula of (2) is as follows: 。 preferably, the throat section airflow deflection angle calculation formula is: 。 Preferably, the rotational flow state analysis method based on angular momentum transfer is based on a simplified assumption, and comprises the steps of incompressible fluid, constant density rho, two-dimensional speed distribution, uniform speed on the same section, and consistency of airflow deflection angle at the outlet of a blade channel and blade angle, wherein only axial and tangential components are considered for speed distribution, and radial speed is ignored. According to mass conservation, the swirl number of the throat section is calculated by taking the swirl state of the blade channel outlet section as an initial value. The cyclone flow control device integrates the influence of structural parameters of the cyclone and the contraction channel on the flow, characterizes the cyclone flow state at the outlet of the head, is closer to the top dead center of the f