摘要
本文从N—S方程及气泡运动与扩散生长方程出发,建立了描述紊流场中气核空化过程的统一数学模型,并据此导出了流场空化相似准则。指出空化相似包括宏观与微观相似两个方面,空化过程实际上是气核从微观尺度向宏观尺度转化的过程,在建立空化起始判据、空化相似准则时,均需考虑这一特点。本文的分析表明,要在减压实验条件下对原型空化进行相似模拟是非常困难的,数值模拟与实验模拟相结合,是解决水利工程中面临的空化现象“比尺影响”问题的可行途径。
Based on the Navier-Stokes equations and the equations for bubble motion and its diffusive growth, an unified mathematical model for describing cavitation process of gas nuclci in a turbulent flow is proposed. From this model, the similitude principles for cavitation of turbulent flows are derived. It is pointed out that cavitation similitude includes two sides: macroscopic and microscopic. Cavitation phe nomenon is in fact the process of criterion transition of gas nuclei in a flow——from microscopic to macros copic, This character should be taken into account when consider cavitation inciption and its similitude. The paper shows that under dcpressurizing conditions, cavitation similitude modelling is very difficult. It is an adoptable mean to combine the methods of numerical and experimental simulating of the phenomenn to overcome the so called 'scale effects' of cavitation in hydraulic engineering.
基金
国家自然科学青年基金
关键词
水工结构
空化
相似模拟
Cavitation, Cavitation inciption, Similitude modelling, Bubble dynamics
