结构参数对拉伐尔喷管空化特性影响的数值模拟

采用CFD方法模拟水在不同结构参数拉伐尔喷管中的空化流动情况。在一定的操作参数下,采用空化泡动力学模型模拟分析拉伐尔喷管不同入口直径、喉部直径、收缩段长度、扩张段长度、扩张段锥角等结构参数对空化效果的影响,并参照正交试验的方法研究各影响因素与水平之间的关系。结果表明：随着喷管喉部直径的减小,空化区域内的汽含率升高,空化数减小,空化效应增强;入口直径与收缩段长度的改变对喷管空化特性的影响不明显;在一定范围内增大扩张段锥角有利于空化强度的增加,但锥角过大反而抑制空化的进行;扩张段长度的增加可以影响空化产生的区域,但对空化强度影响较小;正交试验结果表明在几个结构参数之中,喉部直径的改变对喷管空化特性的影响最大。

Numerical Simulation on Effect of Cavitation Characteristics with Different Structural Sizes in Laval Nozzle

CFD method was used to simulate the cavitation of water in Laval nozzle with different structural sizes.In certain operating parameters,the research used Cavitation Bubble Dynamics Model to simulate the cavitation flow with different inlet diameter,throat diameter,contraction length,expansion length and expansion cone angle of Laval nozzle.In order to determine the optimal structure of the nozzle, orthogonal test was made to find out the relationship between factors and levels.The results show that： with throat diameter decrease,the intensity of cavitation is greater in cavitation area.The change of inlet diameter and contraction length has little effect on cavitation.Expansion cone angle has an impact on the cavitation intensity within a certain range.Increase in length of the expansion can affect cavitation area, but has little effect on the cavitation intensity.Orthogonal test shows that the throat diameter has greatest impact on cavitation among several structural sizes.