不同壁面特性下液膜铺展性能数值模拟

Numerical Simulation of Liquid Film Spreading Performance with Different Wall Features

  • 摘要: 液膜在安全壳表面的流动铺展性能对非能动安全壳冷却系统有重要的影响。采用三维数值模拟方法研究了降膜板表面形貌、接触角与液相雷诺数对液膜铺展性能的影响,并将结果与前人的实验和理论结果对比,吻合良好。研究发现,当降膜板为横向波纹板时液膜完全铺展时间、液膜厚度及界面湍动程度明显大于平板与纵向波纹板,此时波纹板波谷处会有循环流动产生。随接触角的增加或液相雷诺数的减小,液膜逐渐从完整流转变为片状流、溪流、滴状流。在纵向波纹板对液膜的导流与撕裂综合作用下,随接触角的变化,液膜的铺展性能与平板相比也发生较大的变化。

     

    Abstract: The spreading performance of liquid film had crucial effects on the safety of passive containment cooling system. A three-dimensional model was developed to simulate the influences of falling film plate structures, contact angles and Reyonlds numbers on the liquid film spreading performance. The simulation results agree well with the experimental and theoretical results. It is shown that the liquid film spreading time, liquid film thickness and interfacial turbulence on transverse corrugated plate are bigger than those on flat plate and vertical corrugated plate, and the circulation flow is observed at the wave trough of transverse corrugated plate. With the increase of the contact angle or the decrease of Reynolds number, the flow pattern gradually transforms from complete flow to flow with dry patches, rivulet flow and droplet flow. Compared with flat plate, the spreading performance exhibites very different characters on vertical corrugated plate with the changing of contact angle due to its effects of flow diversion and liquid film breaking.

     

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