单旋流驻涡燃烧室流场结构的数值模拟

Numerical Simulation on Single Swirl Trapped-Vortex Combustor Flow

为进一步发展低排放、高效燃烧技术,提出了带导流片的单旋流驻涡燃烧室。改变旋流通道轴向长度及旋流器内外径比,数值分析了其内部燃烧湍流流场。结果表明:旋流通道结构参数及旋流器内外径比对总压损失影响较小,而对燃烧效率影响较大。在多种旋流通道结构参数匹配下均实现了低NO_x排放,最佳匹配结构参数为阻塞比BR=0.6,旋流通道长度与燃烧室长度比Z_s/L_c=0.093,旋流器外径R_o=16mm,内外径比R_i/R_o=0.888;当旋流器外径R_o较小或较大时,内外径比R_i/R_o对排放性能影响不大;当Ro适中时,R_i/R_o对排放性能影响很大,NO_x排放随R_i/R_o的增加呈指数型增加。

A single swirl trapped vortex combustor with guide vane is proposed in order to develop low pol- lution and high efficiency combustion technology, and numerical simulation of combustion turbulence flow was performed by changing axial length of swirler channel and the ratio of inner radius to outer radius. The results show that axial length of swirl channel and the ratio of inner diameter to outer diameter have small impact on total pressure loss, but they have relatively big effect on combustion efficiency. Low NOx emission is obtained by the various matching structure parameter of swirl channels. Optimal matching structure parameter is blockage ra- tio BR=0.6, the ratio of swirler channel length to combustor length Zs/Lc =0.093, outer radius Ro =16mm and the ratio of inner radius to outer radius Ri/Ro =0.888. When swifter outer radius Ro is smaller or bigger, the ra- tio of inner radius to outer radius Ri/Ro, has small impact on NOx emission. When Ro is moderate, Ri/Ro has big impact on NOx emission, NOx emission increases exponentially with the increase of Ri/Ro .