The flash-boiling spray collapse has been widely investigated for multi-hole gasoline direct injection (GDI) injectors. No consensus has been achieved on the collapse process and its mechanism. Herein, the flash-boiling spray behaviors were carefully examined using a multi-hole GDI injector with a larger envelop angle to better observe the jet-to-jet interactions from two view directions. From the front view, the spray collapse occurred as superheat degree (R_p) increased while the sprays under relatively high ambient pressures showed stronger collapse given similar R_p. From the bottom view, the adjacent jets with the closest hole-to-hole distance firstly merged with the increase in R_p, then more jets with relatively larger distance started to merge, and finally the sprays collapsed as R_p further increased. This sort of spatially orderly collapse with the increase in R_p occurred at the beginning of injection and near-nozzle region, contributing to the spray collapse under flash-boiling conditions. It was also found that the merged jets could attract the adjacent jets to some extent with the spray developing. This attraction occurred in the far field and influenced the spray morphology, but had a limited role in the spray collapse. The spatially orderly collapse in such a nozzle configuration delivers a more general understanding of the flash-boiling induced collapse and it will be of help in injector design optimization.

中文翻译：

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使用具有宽包络喷射角度的多孔喷射器深入了解闪沸条件下的喷射与喷射之间的相互作用

已经对多孔汽油直喷 (GDI) 喷射器的闪沸喷雾坍塌进行了广泛的研究。崩溃过程及其机制尚未达成共识。在这里，使用具有更大包络角的多孔 GDI 喷射器仔细检查了闪沸喷雾行为，以更好地从两个观察方向观察射流与射流的相互作用。从正面看，喷雾塌陷随着过热度（R _p）的增加而发生，而在相对较高的环境压力下，喷雾在相似的 R _p下表现出更强的塌陷。从底部看，孔距最近的相邻射流随着R _{p的增加首先合并}，然后更多距离相对较大的射流开始合并，最后随着 R _p进一步增加，喷雾崩溃。这种随着 R _p增加的空间有序塌缩发生在喷射开始和喷嘴附近区域，有助于闪沸条件下的喷雾塌缩。还发现合并的射流可以在一定程度上吸引相邻的射流随着喷雾的发展。这种吸引力发生在远场并影响喷雾形态，但在喷雾塌陷中的作用有限。这种喷嘴配置中的空间有序塌陷提供了对闪沸引起的塌陷的更一般理解，这将有助于喷射器设计优化。