汽油/乙醚喷雾宏观蒸发特性实验研究

Experimental Investigation of Evaporating Spray Macroscopic Characteristics for Gasoline/Diethyl-Ether Blended Fuel

本文基于纹影光路在定容燃烧弹中开展了汽油/乙醚混合燃料的宏观喷雾蒸发特性实验研究。通过高速摄像机捕获到亚临界工况(0.5 MPa,349~516 K),超临界工况(3.8 MPa,516 K)的蒸发态喷雾发展过程并提取蒸汽相贯穿距,喷雾锥角以及燃油蒸发率等表征参数。亚临界工况下,研究结果显示低环境温度条件下掺混乙醚可以加快燃料的蒸发速率,而高环境温度条件下掺混乙醚对于改善燃料蒸发速率的影响不明显。当燃油喷雾由亚临界工况转入超临界工况时,纯乙醚的蒸汽相燃料生成速率由于燃料蒸发机制发生改变反而得到抑制。

In this research work,the spray macroscopic characteristics of gasoline/diethyl-ether blended fuel were investigated in a constant combustion chamber via schlieren optical setup.Subcritical ambient conditions(0.5 MPa pressure,349~516 K temperature)and supercritical condition(3.8 MPa pressure,516 K temperature)were respectively chose to simulate evaporating spray propagation process.By means of in-house post-processing code,macroscopic characterizing parameters like vapor tip penetration,spray angle and fuel evaporation rate are extracted from raw schlieren images.The results show that under subcritical conditions,blending diethyl-ether into gasoline is prone to enhance fuel evaporation rate at low ambient temperature,while this enhancing effect tends to be mitigated with the increase of ambient temperature.Moreover,when the ambient condition is converted from subcritical state to supercritical state,the evaporating rate of pure diethyl-ether is restrained due to fuel evaporation mechanism.