基于LBM方法的超亲水/疏水组合表面的沸腾冷凝特性研究

Study on boiling bondensation characteristics of superhydrophilic hydrophobic composite surface based on LBM method

中文关键词: 表面  沸腾冷凝  伪势模型  DDF  多相流  数值模拟

英文关键词: surface  boiling condensation  pseudo-potential model  DDF  multiphase flow  numerical simulation

中文摘要:

      基于单组分多相流格子Boltzmann方法结合精确差分法建立了汽液相变模型，运用伪势模型以及双分布函数，结合所提出的沸腾冷凝相变模型，对微小空间内超亲水和超疏水组合表面下汽液共存沸腾时两个汽泡合并、生长、离开水平面以及蒸汽冷凝凝结成两个液滴融合、脱落的过程进行了研究。着重分析了重力加速度对汽泡脱离直径和汽泡脱离时间的影响以及流固作用强度对接触角的影响，最后拟合出了对应关系，并对汽泡和液滴运动过程进行了分析。研究发现与现有已发表的对应关系和公开实验结果基本吻合，并得出结论：随着重力加速度的增大，汽泡脱离直径和汽泡脱离时间均呈现出减小的趋势；接触角随着流固作用强度的增大呈现出减小的趋势；沸腾过程受热产生的蒸汽在模型内部在平衡移动原理作用下向着冷源移动，冷源液化消耗近似等量蒸汽产生水滴逐渐成长落入水中，实现了系统内热力平衡和循环过程。

英文摘要:

      Based on the single-component multiphase flow lattice Boltzmann method combined with the exact difference method, a vapor-liquid phase transition model is established. The pseudo-potential model and dual distribution function are combined with the boiling-condensation phase transition model proposed.The coexistence of vapor and liquid co-existing under the surface of a superhydrophobic combination boiled, the two bubbles merged, grew, left the horizontal plane, and the steam condensed and condensed into two droplets to fuse and fall off.The effects of gravity acceleration on bubble exit diameter and bubble exit time, as well as the effect of fluid-solid strength on the contact angle are analyzed. Finally, the corresponding relationship is fitted, and the process of bubble and droplet movement is analyzed.The study found that it is basically consistent with the existing published correspondence and public experimental results,and concluded that as the acceleration of gravity increases, both the bubble exit diameter and the bubble exit time show a decreasing trend; the contact angle varies with the increase in fluid-solid interaction intensity shows a decreasing trend; the steam generated during the boiling process moves toward the cold source under the principle of equilibrium movement inside the model, and the liquefaction of the cold source consumes approximately the same amount of steam to achieve the thermal balance and cycle process in the system.