DME闪急沸腾喷雾特性的试验与数值模拟研究

Investigation and Numerical Simulation of DME Flash Boiling Spray Characteristics

在压力定容室内,利用数字粒子图像速度场仪(DPIV)对二甲醚(DME)闪急沸腾喷雾特性,以及DME和柴油的常规喷雾特性开展了试验研究;建立了适用于DME闪急沸腾喷雾的宏观现象学模型,并将该模型与KIVA程序相耦合,藉此对DME闪急沸腾喷雾特性进行了数值模拟。研究结果表明:与柴油常规喷雾相比,DME闪急沸腾喷雾贯穿距较短,但喷雾锥角较大;喷雾初始段的计算值与试验测量值吻合较好,但喷雾后期的吻合程度稍差。计算研究表明:DME闪急沸腾喷雾体前端两侧存在着明显的涡环结构,喷雾场中DME的气相浓度大幅度高于柴油喷雾的气相浓度,且其索特平均直径(SMD)比柴油小得多。

The flash boiling spray characteristics of dimethyl ether（DME） were investigated by digital particle image velocimetry （DPIV） in a constant volume chamber. Based on DME spray experiments, a macro-phenomenal model was developed for DME flash boiling spray, and then this model was coupled with KIVA program to simulate the DME flash boiling spray. The calculated and measured results show that the spray tip penetration of DME is shorter than that of the diesel fuel, but the spray cone angle of DME is larger. It is also found that the calculated DME macroscopic spray characteristics at the initial injection stage are in good agreement with the measured results, but at the later injection stage, there is a little difference between the predicted and measured results. It is also found from simulated results that there is an obvious vortex ring on the each side at the front of DME flash boiling spray, and the concentration field of DME is also better than that of diesel fuel spray. The SMD of DME spray is also smaller than that of diesel fuel spray.