液体射流在旋转气流中的雾化机理研究

Mechanisms of Atomization of a Liquid Jet Surrounded by Swirling Airstreams

对旋转气流中的空心柱形液体射流的雾化过程进行了数值模拟。结果表明:Reynolds数Re、Weber数We、空心柱内部及外部气液密度比Qa和Qb及喷嘴内半径与液膜厚度比Ah,在射流的雾化过程中均起不稳定性的作用;空心柱射流内部的气流旋转强度Ea在雾化过程中加强了自由面上的轴对称扰动和非轴对称扰动;空心柱射流外部的气流旋转强度Eb削弱了自由表面上的轴对称扰动强度,却加强了自由表面的非轴对称扰动。此外,Eb的增加,能大大增加扰动种类。

The atomization of the high-speed hollow cylindrical liquid jet was simulated in this paper. The results show that Reynolds number Re, Weber number We, the density ratios of gas to liquid (Q_a and Q_b) in the inner and outer part of the hollow jet and the ratio of the inner radius to liquid film thickness (A_h) all exert an unstable function in the jet atomization process. The swirling intensity (E_a) in the inner part of the hollow jet increases the growth rates of the asymmetric disturbance and axisymmetric disturbance during the jet atomization, and the swirling intensity (E_b ) in the exterior of hollow jet weakens the axisymmetric disturbance growth rate of the free surface while it intensifies the asymmetric disturbance. Moreover, E_b increasing can largely extend the kinds of the disturbance.