气体速度对液膜在预膜板表面流动形态影响的LBM模拟

为了探究气流剪切作用对航空燃油在气动雾化喷嘴预膜板上流动形态的影响,首先对基于相场理论的两相流格子Boltzmann模型进行修正,并通过经典算例验证了修正后模型的准确性和可靠性.随后利用该模型模拟了同向气流驱动下液膜在水平预膜板表面上的流动,分析了气流速度对液膜流动形态的影响规律.研究表明,该模型可准确追踪具有大密度比的气液相界面的形态变化;气液剪切速度差会诱发两相界面出现Kelvin-Helm-holtz不稳定性现象,因而当气体速度升高时,气液剪切速度差增大,不仅液膜流动速度随之增高,且在铺展阶段液膜会产生较高振幅的波浪面并加快铺展过程,自由表面波动增强.

LBM analysis of the effects of gas velocity on the flow pattern of liquid film on the pre-filming surface

In order to investigate the shearing effects of airflow of aviation fuel on the flow pattern on the pre-filming surface in the airblast atomizers,this paper firstly modifies the phase-field-based lattice Boltzmann model for two-phase flows in the literature,then verifies its accuracy and reliability through a benchmark case.Afterward,the model is used to simulate the flow of liquid film on the pre-filming surface driven by co-current airflow,and the influence of airflow on the flow pattern of liquid film under different air velocities has been analyzed.Numerical results indicate that the present model can accurately track the morphological changes of the gas-liquid interface with a large density ratio.The velocity difference between gas and liquid induces the Kelvin-Helmholtz instability at the interface.Therefore,when the gas velocity increases,the shearing effects of gas enhances arousing higher amplitude surface-waves.Besides,the spreading process of liquid film on the pre-filming surface is accelerated.The volatility of free surface is enhanced as well.