旋流作用下突扩燃烧室内冷态流场的 PIV 分析

摘要

旋流作用下突扩燃烧室内流场特性的研究对保证燃烧室的正常工作具有重要的意义。利用PIV技术对燃烧室内冷态流场的结构进行了实验诊断与分析，获得了不同实验条件下燃烧室内的速度场、回流区分布和流场内涡的变化规律。研究表明，当入口空气压力变化时，燃烧室内冷态流场可以保持稳定结构，均包含角回流区、中心回流区及剪切层结构。沿燃烧室轴向方向，中心回流区的宽度先增大再减小。随着入口压力的提高，燃烧室内冷态流场的回流区宽度及回流区长度缩短，最大回流速度增大，回流区中心位置向入口移动。同时，在燃烧室冷态流场中会出现由旋流作用引发的涡旋进动现象。%The characteristics of flow filed under swirling play an important role in the stable work of the central-dump combustor.In this paper,the experimental diagnosis and analysis of the cold-flow field structure of the swirl-stabilized dump combustor are carried out by using PIV. The purpose is to obtain the distribution of the velocity field,the recirculation zone structure and the vorticity of the cold-flow field under different experimental conditions.The experimental results reveal that the cold-flow structure of the swirl-stabilized dump combustor is stable under different inlet air pressures,including a corner recirculation zone,a central recirculation zone and a shear layer.The width of the central recirculation zone increases first and then decreases along the axial direction of central-dump combustor.The length and width of the recirculation zone decrease with the increase of the inlet air pressure.Furthermore,the maximum reverse flow velocity of the recirculation zone is enhanced and the central position of the recirculation zone in swirl-stabilized dump combustor under cold-flow conditions moves closer to the inlet of the cen-tral-dump combustor as the inlet air pressure increases.And the precessing vortex core is formed by swirl in the cold-flow filed of the swirl-stabilized dump combustor.