瓣高宽比对波瓣强迫混合排气系统性能影响

以某涡扇发动机波瓣强迫混合排气系统为研究对象,在波瓣数以及波瓣长度不变的情况下,分别固定波瓣宽度改变波瓣高度和固定波瓣高度改变波瓣宽度,得到了一系列不同波瓣高宽比的几何模型,并对其进行了三维数值模拟研究,获得了不同高宽比对波瓣混合器流场、热混合效率和总压恢复系数的影响规律.结果表明:在混合器出口处,当高宽比在2~5范围内变化时,热混合效率在波瓣宽度和高度分别不变时,随高宽比的增加,分别呈现出不断增大以及不断减小的趋势;当宽度不变时,总压恢复系数随高宽比的增大而减小,当高度不变时,总压恢复系数随高宽比的增大而增大.

Effect of ratio of height to width of lobe on the performance of a lobed mixer in a forced mixing exhaust system

Geometric and numerical simulation models of lobed mixer with variation of the ratio of height to width (h/b) of lobe were created based on a lobed mixer in the forced mixing exhaust system of turbofan engine with constant lobe number and lobe length.Though three-dimensional numerical simulation,the principle of the effect of different ratios of height to width in a forced mixing exhaust system was obtained.The results show that at the exit section of the force mixing exhaust system,when the width of lobe is constant,the thermal mixing efficiency rises as h/b increases;however,when the height of lobe is constant,the mixing efficiency declines with rise of h/b.Besides,as h/b augments,the total-pressure recovery coefficient decreases if the width of lobe is unchanged,or increases if the height of lobe is invariable.