双喷嘴水平对置撞击流混合器内湍流流动及混沌特性

应用激光多普勒测速系统, 对双喷嘴水平对置撞击流混合器内的速度场进行测量, 并且分别采用湍流理论和混沌理论对所测得的瞬时速度场进行分析, 研究其瞬时速度场内湍流特性参数(速度脉动均方根、湍流强度和湍动能)以及混沌吸引子的特征参数(关联维、Kolmogorov熵和最大Lyapunov), 得出该参数随喷嘴间距变化和进口雷诺数变化的分布情况, 并且得到有利于提高混合器内微观混合效果的最优工况。通过混沌分析得到双喷嘴水平对置撞击流混合器的瞬时速度场具有混沌特征和分形特性。研究结果表明:流场内的湍流参数和混沌参数均与进口雷诺数呈正相关关系, 但是两参数却随着喷嘴间距的增加, 呈先增加后减小的变化趋势, 从而可以得到在实验考察范围内L=3d为最合适的喷嘴间距。

Turbulence flow and chaotic characteristic in the dual nozzle opposed impinging stream mixer

Phase Doppler Anemometry(PDA) was used to measure the instantaneous velocity of flow field in dual nozzle opposed impinging stream mixer. Based on the turbulence theory and chaos characteristic, the velocity field was analyzed in mixer and the change of turbulence characteristic parameters(velocity root mean square, turbulence intensity and turbulence kinetic energy) and chaotic characteristic parameters(correlation dimension, Kolmogorov entropy and the largest Lyapunov exponent) were studied by changing nozzle distance and various inlet Re number in order to achieve optimal conditions of microcosmic mixture. The flow field in SISM was chaotic and fractal. The chaos characteristic parameters and turbulence parameters presented positive correlation with Re number, but these parameters all increased and then decreased with the increasing nozzle distance. The proper nozzle distance L=3d beneficial to the microcosmic mixture was obtained based on the correlation.