某型航空发动机用离心喷嘴燃油空间分布特性试验

建立了平面激光诱导荧光(PLIF)用于燃油分布特性测量的试验装置及其校正方法,并验证了校正方法的有效性.PLIF和平面激光散射(PLS)方法的燃油分布特性测量结果表明PLS方法对直径小于50μm的液滴存在非线性效应使小液滴集中区燃油分布测量结果偏大,PLIF方法适合燃油分布特性测量.利用PLIF方法从喷雾锥角、燃油周向分布不均匀度和分布指数等方面综合评价燃油空间分布特性.偏心和尺寸大小不等的凹槽等分布不均匀的表现形式表明:造成燃油分布不均匀的因素包括喷嘴内部通道表面粗糙度、喷射孔圆度和零件之间的同轴度.利用PLIF方法研究雾锥在供油压差分别为0.14,0.25,2.5MPa时雾锥沿喷射方向的发展过程,液滴随雾锥发展逐渐从环形集中区分散到整个雾锥横截面,并且液滴分散过程随供油压差增加而加快. 

Experiment of fuel distribution of pressure-swirl atomizers for aero-engine

The experimental unit and correction method for estimation of performance of fuel distribution based on planar laser induced fluorescence (PLIF) method were established, and the correction method was validated. The comparisons between results of PLIF method and planar laser scattering (PLS) method indicate that, the results of PLS method overrepresents droplet concentration for droplets less than 50μm and PLIF is suitable for fuel distribution measurement. To make sure the quality of machining and performances of the atomizers, the distributions of droplets were evaluated comprehensively by PLIF method in terms of spray cone angle, non-uniformity of circumferential distribution and patternation index, and then, the results of eccentricity and grooves of different sizes for the poor droplets distribution show that, the factors for non-uniformity include the roughness of internal flow wall, roundness of nozzle and coaxiality of parts. The opening processes of spray cones in the direction of ejection were visualized by PLIF method at pressure differential of 0.14, 0.25 and 2.5 MPa, respectively, and the droplets dispersed from annulus to round in cross-sectional plane with development of the spray. Furthermore, the rate of droplets dispersion increased with the growing pressure differential of fuel.