Ezzatneshan Eslam, Vaseghnia Hamed
Aerospace Engineering Group, Department of New Technologies Engineering, Shahid Beheshti University, Tehran, Iran.
Phys Rev E. 2020 Nov;102(5-1):053309. doi: 10.1103/PhysRevE.102.053309.
A computational technique based on the pseudo-potential multiphase lattice Boltzmann method (LBM) is employed to investigate the collapse dynamics of cavitation bubbles of various liquids in the vicinity of the solid surface with different wettability conditions. The Redlich-Kwong-Soave equation of state (EoS) that includes an acentric factor is incorporated to consider the physical properties of water (H_{2}O), liquid nitrogen (LN_{2}), and liquid hydrogen (LH_{2}) in the present simulations. Accuracy and performance of the present multiphase LBM are examined by simulation of the homogenous and heterogeneous cavitation phenomena. The good agreement of the results obtained based on the present solution algorithm in comparison with the available data confirms the validity and capability of the multiphase LBM employed. Then, the cavitation bubble collapse near the solid wall is studied by considering the H_{2}O, LN_{2}, and LH_{2} fluids, and the wettability effect of the surface on the collapse dynamics is investigated. The obtained results demonstrate that the collapse phenomenon for the H_{2}O is more aggressive than that of the LH_{2} and LN_{2}. The cavitation bubble of the water has a shorter collapse time with an intense liquid jet, while the collapse process in the LN_{2} takes a longer time due to the larger radius of its bubble at the rebound. Also, this study demonstrates that the increment of the hydrophobicity of the wall causes less energy absorption by the solid surface from the liquid phase around the bubble that leads to form a liquid jet with higher kinetic energy. Therefore, the bubble collapse process occurs more quickly for hydrophobic surfaces, regardless of the fluids considered. The present study shows that the pseudopotential LBM with incorporating an appropriate EoS and a robust forcing scheme is an efficient numerical technique for simulation of the dynamics of the cavitation bubble collapse in different fluids.
采用基于伪势多相格子玻尔兹曼方法（LBM）的计算技术，研究不同润湿性条件下固体表面附近各种液体空化泡的溃灭动力学。在当前模拟中，纳入了包含偏心因子的Redlich-Kwong-Soave状态方程（EoS），以考虑水（H₂O）、液氮（LN₂）和液氢（LH₂）的物理性质。通过对均匀和非均匀空化现象的模拟，检验了当前多相LBM的准确性和性能。与现有数据相比，基于本求解算法获得的结果吻合良好，证实了所采用的多相LBM的有效性和能力。然后，研究了H₂O、LN₂和LH₂流体在固体壁附近的空化泡溃灭情况，并研究了表面润湿性对溃灭动力学的影响。所得结果表明，H₂O的溃灭现象比LH₂和LN₂更剧烈。水的空化泡溃灭时间较短，伴有强烈的液体射流，而LN₂中的溃灭过程由于其在反弹时气泡半径较大而耗时较长。此外，本研究表明，壁面疏水性的增加会导致固体表面从气泡周围液相吸收的能量减少，从而形成具有更高动能的液体射流。因此，无论考虑何种流体，疏水性表面的气泡溃灭过程都发生得更快。本研究表明，结合适当的EoS和强大的强迫方案的伪势LBM是模拟不同流体中空化泡溃灭动力学的一种有效数值技术。
