The influence of the cavitation effect on the diesel engine nozzle is based on the following aspects: flow and spray characteristics, cavitation erosion on the nozzle wall, and pressure fluctuations of diesel fuel in the system. The first two have been extensively studied, but the research on the third one is rather limited. In this article, the synchronous acquisition, data processing system of cavitation, pressure fluctuations of diesel fuel, and spray characteristics inside the transparent nozzle were examined, then the direct correspondence among pressure fluctuations and cavitation phenomenon was explored. Experimental studies under steady injection pressure and fixed needle lift show that: during the process of transforming hole-to-hole string cavitation to needle-originated string cavitation, the pressure fluctuation amplitude increases significantly. String cavitation under low pressure is easily converted into geometry-induced cavitation due to morphological instability, which has a large disturbance to the spray cone angle. String cavitation under high pressure is more intense with the pressure fluctuation is relatively large and its intensity is weaker than the geometry-induced cavita-tion intensity under the same pressure; however, both the pressure fluctuation amplitude and spray cone angle are much larger. The peak pressure of string cavitation is higher than that of geometry-induced cavitation. In the process of the disappearance, fracture, and fusion of string cavitation, the pressure fluctuation amplitude increases significantly. The results of this experiment play a crucial role in the effective control of pressure fluctuations in the system.

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空化对光学柴油喷嘴压力脉动及喷雾特性影响的实验研究

空化效应对柴油机喷嘴的影响基于以下几个方面：流量和喷雾特性，喷嘴壁上的空化腐蚀以及系统中柴油的压力波动。对前两个进行了广泛的研究，但是对第三个的研究却相当有限。本文研究了空化的同步采集，数据处理系统，柴油的压力波动以及透明喷嘴内部的喷雾特性，然后探讨了压力波动与空化现象之间的直接对应关系。在稳定的注射压力和固定的针升力下进行的实验研究表明：在将孔对孔的串空化转变为源自针的串空化的过程中，压力波动幅度明显增加。由于形态的不稳定性，低压下的弦线空化容易转换成几何形状的空化，这对喷锥角产生了很大的干扰。与相同压力下的几何诱导空化强度相比，高压下的弦空化强度更大，压力波动较大，强度弱。但是，压力波动幅度和喷雾锥角都大得多。串空化的峰值压力高于几何诱导的空化。在弦空化消失，破裂和融合的过程中，压力波动幅度会显着增加。