非旋空气对分级贫油直喷燃烧室流动和雾化影响的实验研究

Experimental Study on Effects of Non-Swirling Air on Flow and Atomization in Lean-Direct-Injection Staged Combustor

针对中心分级贫油直接喷射燃烧室头部,采用粒子图像测速技术、平面激光Mie散射技术以及粒径测量技术,对比研究了非旋流空气与旋流空气四种不同的进气比例对燃烧室流动特性、喷雾特性以及燃油粒径分布特征的影响。研究发现:在常温常压状态,随着非旋流空气比例的增高,中心回流区不断缩小直至消失,预燃级燃油锥角不断减小,雾化受到阻碍,主燃级射流由向主燃级偏转逐渐转为向预燃级偏转,主油破碎效果先恶化后优化。在旋流器压降为1%和2%工况下,非旋流空气对两级燃油雾化均有抑制作用,随着非旋流空气比例的升高,空气对两级燃油雾化的阻碍作用呈现先增强后削弱的趋势,在压降为3.3%工况,非旋流空气比例对燃油雾化的影响较小。结果表明:非旋流空气与旋流空气比例为1∶2时,能够得到较为良好的流场结构、燃油分布和雾化效果,综合性能较好,是最优方案。

In this paper,four different proportions of non-swirling air and swirling air in central staged Lean Direct Injection(LDI)combustor are studied.Particle image velocimetry technology,Mie scattering technology and particle size measurement technology were used to study the effect of those structures on air dynamics,spray characteristics and particle size distribution of fuel.Researches show that,under normal temperature and pressure,with the increase of the proportion of non-swirling air,the central reflux area continues to shrink until it disappears,the cone angle of pilot stage fuel continues to decrease,the atomization effect becomes worse,the main stage jet deflects gradually from the main stage to the pilot stage,and the crushing effect of main fuel deteriorates first and then optimizes.When the pressure drop of the cyclone was 1%and 2%,non-swirling air had inhibitory effect on the fuel atomization of both stages and with the increase of the proportion of non-swirling air,the hindering effect of air on fuel atomization increased and then weakened.When the pressure drop of the cyclone was 3.3%,the proportion of non-swirling air had little effect on fuel atomization.The results show that when the ratio of non-swirling air to swirling air is 1:2,better flow field structure,fuel distribution and atomization effect can be obtained,and the comprehensive performance is better,which is the optimal scheme.