超声速内流场横向喷流的流动与混合特性实验研究

为研究超声速内流场中横向喷流的流动与混合特性,将丙酮蒸汽加入喷流介质,用平面激光诱导荧光(PLIF)技术对流场中流向中心截面和横截面上的丙酮进行成像,研究了喷流的运动轨迹、流场结构、混合方式,以及参数对喷流流动与混合的影响。结果表明:喷流柱的波动失稳及喷流剪切层中生成的大尺度结构有助于增强喷流与主流在近场的混合;提高出口马赫数会导致剪切层失稳以及出现大尺度结构的位置移向下游,不利于改善近场的混合;增大喷口直径能增加喷流在展向的扩展,升高喷流总压能增加喷流在展向和横向的扩展,并使出现大尺度结构的位置靠近上游;在喷注流量相同条件下,采用小喷注面积高总压喷注更利于增强混合。

Experimental Studies of Flow and Mixing of Transverse Jets in Supersonic Crossflows

To study the flow and mixing of a transverse jet in a supersonic crossflows,the effect of the jet trail,flowfield structure,mixing manner,and jet parameters were studied experimentally by using planar laser-induced fluorescence technique to image the acetone flowing to the center of the streamwise and on the crosswise planes in this paper,while the acetone vapor was adulterated into the jet.The experimental results showed that fluctuating and the stabilization losing of the jet and the large-scale structures created in the shear layer between the jet and the main flow were able to enhance the mixing in the near-flowfield;increasing jet Mach number would cause the locations where the shear layer coming about unstable and the large-scale structures being created to move downstream,which weakened the mixing efficiency;increasing the injection port diameter would cause the jet to extend in the spanwise direction;increasing the jet stagnation pressure would cause the jet to extend both in the spanwise and crosswise directions and cause the location where the large-scale structure being created nearer to the upstream.Under the equal mass flow rate,injection with the small jet area and the high jet stagnation pressure had excellent mixing efficiency.