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射流在马赫数为2的超声速横流中的穿透特性。研究表明，在一定的喷射压力下，喷射压力上升阶段的脉冲射流穿透深度大于喷射压力下降阶段的脉冲射流穿透深度。这种滞后现象是由于脉冲射流产生的向上流动类似于向注射壁倾斜的段塞。数值模拟结果表明，在每个脉冲周期内都有涡环产生。它们控制射流穿透并促进注入剂与横流空气的混合。基于这些实验和数值计算结果，我们得出结论，脉冲喷射可以通过改变其频率来控制射流的穿透和混合。

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.