Enhancement of Fuel Mixing and Jet Penetration using Pulsed Injection into a Supersonic Flow

本文通过实验和数值模拟研究了脉冲喷射对马赫数为2的超音速横流的侵彻特性。研究表明，在一定的注射压力值下，脉冲射流在注射压力上升阶段的穿透比在注射压力下降阶段的穿透要大。这种滞后是由于脉冲射流产生的向上流动，就像一个向喷射壁倾斜的弹状物。数值模拟表明，在每个脉冲周期内都会产生涡环。它们控制着射流的穿透，促进了注射剂与横流空气的混合。基于这些实验和数值结果，我们得出结论：脉冲喷射可以通过改变频率来控制射流的侵彻和混合。

This research experimentally and numerically investigated the penetration characteristics of the pulsed injection into Mach 2 supersonic crossflow. This research revealed the pulsed jet penetration in a rising phase of injection pressure was higher than that in a declining phase of injection pressure at a certain value of injection pressure. This hysteresis was owing to the upward flow produced by the pulsed jet like a slug which inclined toward the injection wall. The numerical simulations revealed the vortex rings was generated in each pulse cycle. They dominated the jet penetration and promoted mixing of the injectant with crossflow-air. Based on these experimental and numerical results, we conclude that the pulsed injection could control the jet penetration and mixing by changing its frequency.