基于格子玻尔兹曼方法的近壁区空化泡生长溃灭过程模拟

Simulation of growth and collapse processes of near-wall cavitation bubbles with lattice Boltzmann method

基于格子玻尔兹曼热流耦合模型,兼顾温度场与流场的相互影响,对近壁区空化泡的生长和溃灭过程开展了系统研究,分析了泡壁无量纲距离和初始输入温度对空化泡演化过程和溃灭强度的影响,并对比了被动标量模型与热流耦合模型的差异。结果表明:空化泡受壁面限制,生长过程中无法保持圆形,其最大半径与泡壁无量纲距离之间存在幂函数关系,当泡壁无量纲距离大于1.6时,则为线性关系;空化泡最大半径与输入能量为线性关系,与初始输入无量纲温度之间存在幂函数关系;热流耦合模型考虑了高温对表面张力的影响,与被动标量模型模拟结果相比,其溃灭阶段获得的射流体积更大,微射流更集中,但溃灭强度更小。

Based on the coupled hydro-thermodynamic lattice Boltzmann model,and considering the interaction between the flow field and the temperature field,the growth and collapse processes of the cavitation bubbles in the near wall region were systematically investigated.The influence of the wall-bubble dimensionless distance and initial input temperature on the bubble morphology evolution process and the collapse intensity were analyzed.Furthermore,the differences between the results obtained by the coupled hydro-thermodynamic model and the passive scalar model were proposed.The results indicate that the relationship between the dimensionless distance and the maximum radius represents a power law if the bubble cannot keep its roundness during the growth stage due to the restriction of the wall.It shows a linear relationship if the dimensionless distance is greater than 1.6.A linear relationship exists between the input energy and the maximum radius,while a power law exists between the initial input dimensionless temperature and the maximum radius.The effect of high temperature on the gas-liquid interface is considered in the coupled hydro-thermodynamic method and compared to the passive scalar method,a larger jet volume and more concentrated jets with lower collapse intensity can be obtained during collapse stage.