航空发动机中直通式篦齿密封腔内流动和换热的实验研究

Experimental Research on Lobed Exhaust Ejection Mixer

作者自行设计了大尺寸吸气式篦齿换热风洞实验台并通过它对篦齿腔中的内部流场进行了详细的研究 ,得出了篦齿腔中速度场和压力场及流场内部旋涡分布规律。同时测量了在不同雷诺数、齿顶厚和齿隙比工况下 ,篦齿腔内二维流动状况及旋涡分布 ,分析得出不同雷诺数和齿隙比对篦齿腔内部流场的影响。并且测量了篦齿顶板表面的温度和换热系数的分布 。

A conventional annular exhaust ejection mixer and three lobed exhaust ejection mixers were tested at atmospheric pressure and low exhaust velocity conditions to study the effects of three structure parameters lobe exit angles α/β ,relative mixing length L/D and lobe penetration H/H o on the aerodynamic characteristics of the lobed exhaust ejection mixers.The results show that the aerodynamic characteristics of the lobed exhaust ejection mixer are obviously better than those of an annular exhaust ejection mixer.The effect of the lobe exit angle α/β on the performance of the mixer is not so distinct if no separation occurs inside the lobes,but the increase of α/β is advantageous to the compromise between aerodynamic performance and weight.The increase of relative mixing length L/D can improve the aerodynamic performance.An optimum L/D exists for the compromise between aerodynamic performance and weight.The effect of the lobe penetration H/H o on the aerodynamic performance of the lobed exhaust ejection mixer is significant.The enhancement of the lobe penetration H/H o is advantageous to the flow mixing,but disadvantageous to the pumping ability.