竖直流道宽度对气泡运动行为影响的数值模拟

用数值方法模拟了竖直通道宽度对气泡在液体中的非定常运动、变形以及传热特性的影响。在这个模拟中,界面跟踪采用了VOF方法,并采用PL IC进行界面重构。主流场计算采用有限容积方法将控制方程离散,其中扩散项采用中心差分格式,对流项采用一阶迎风格式。用成熟的S IM PLE算法求解N-S方程的速度与压力的耦合问题。引入CSF模型处理运动界面的表面张力。利用所编制的程序计算了竖直流道中的单个气泡的形状、运动特性以及气泡内外流场与传热特性,并对竖直通道宽度在不同情况下,对气泡的形状、运动特性以及传热特性进行了进一步的研究。得到了一系列有价值的结果,并与实验结果比较。表明数值模拟结果与实验结果吻合的较好。

A numerical simulation on effects of vertical channel wide on deformation and heat transfer of a rising gas bubble

The motions,deformation and heat transfer characteristic of a rising gas bubble through the liquid in a vertical channel are numerically predicted in this paper.In this simulation,the VOF method was used to track the interface and the PLIC method was employed to reconstruct the interface.A tension model,called CSF,was introduced to dispose the surface tension.The governing equations were solved by using a finite volume method on a body-fitted coordinates mesh. Independent variables were arranged at collocated grids.The central difference and upwind schemes were used to discrete the diffusion terms and convection terms in the governing equations,respectively.The decoupling between pressure and velocity was solved by means of SIMPLE algorithm.By using the methods and models,motions,deformation and heat transfer characteristic of a rising bubble in a gas liquid two-phase flows system were calculated.Meanwhile,the effects of the vertical channel wide on motion,deformation and heat transfer of the bubble were also investigated.The numerical results are in good agreement with the available experimental data.