电邦德数影响下无水乙醇的荷电微射流不稳定性

Experimental research on the evolution of the atomization mode and the jet instability of charged micro-jets of anhydrous ethanol has been carried out based on high-speed photography and small-scale PIV technology. The microscopic evolution process of charged micro-jets of anhydrous ethanol has been accurately captured, and the evolution characteristics of jet instability in different atomization modes under the influence of the electric Bond number and its influence law on the atomization characteristics of micro-jets have been discussed. The experimental results show that: the non-axisymmetric radial perturbation of the jet runs through the entire jet atomization mode interval; as the electric Bond number continuously increases, the jet deviation shows a trend of first increasing and then decreasing, while the pulsation range of its uncertainty continuously increases in the cone-jet mode, and after transitioning to the multi-jet mode, the pulsation range gradually decreases to zero and then gradually increases again; in the cone-jet mode, the jet core area and the velocity direction deviate from the axis, and the jet velocity significantly drops compared with that in the spindle mode; in the multi-jet mode, the velocity in the jet core area significantly rebounds, but the velocity distribution among the multi-jets varies greatly under different electric Bond numbers; in most cases, the streamlines at the jet boundary are rather disordered and lack symmetry, but a stable multi-jet stable atomization morphology is maintained within a very small interval of the electric Bond number from 13.30 to 13.60, and the velocity in the jet core area reaches a peak.

基于高速摄像及小尺度PIV技术对无水乙醇荷电微射流雾化模式的演变及射流不稳定性进行了实验研究。精确捕捉了无水乙醇荷电微射流的显微演变过程,探讨了电邦德数影响下不同雾化模式的射流不稳定性演变特征及其对微射流雾化特性的影响规律。实验结果表明:射流的非轴对称性径向扰动贯穿于整个射流雾化模式区间;随着电邦德数不断增大,射流偏离度呈先增大后减小的趋势,而其不确定性的脉动范围在锥射流模式下不断增大,过渡到多股射流模式后,脉动范围逐渐减小至零,而后再逐渐增大;锥射流模式下,射流核心区及速度方向均偏离轴心,射流速度较纺锤模式明显回落;多股射流模式下,射流核心区速度明显回升,但不同电邦德数下多股射流之间的速度分布差异较大;多数情况下,射流边界处的流线较为紊乱,缺乏对称性,但在电邦德数为13.30~13.60的极小区间内保持稳定的多股射流稳定雾化形态,射流核心区速度达到峰值。