方腔内Al2O3-H2O纳米流体热毛细对流的格子Boltzmann模拟

Lattice Boltzmann Simulation of Thermal Marangoni Convection of Al2O3-H2O Nanofluids in Square Cavity

  • 摘要: 采用格子Boltzmann方法研究纳米颗粒形状影响下方腔内纳米流体热毛细对流的强化传热效果,主要分析了纳米粒子体积分数、颗粒形状以及Marangoni数Ma等相关参数对于纳米流体热毛细对流换热过程的影响。结果表明:长径比(长/半径)对纳米流体换热效果有影响,形状因子越大,平均NuNuave越大。随着体积分数的增加,棒状、盘状和正方体状纳米颗粒均使热毛细对流的Nuave数减少,球状纳米颗粒条件下热毛细对流的Nuave数增加。Ma数越大,纳米流体热毛细对流的自由表面速度越大,对流换热效果也随之增强。

     

    Abstract: The heat transfer effect of nanofluid in thermal marangoni convection was studied by using lattice Boltzmann method. The effects of nanoparticle volume fraction, particle shape and marangoni number(Ma) were analyzed. As a result, the heat transfer effect of nanofluids was affected by the ratio of length to radius. The larger the shape factor, the larger the average Nu number. As the volume fraction increased, cylinder, platelet, and brick nanoparticles all could reduce the average Nu number of thermal marangoni convection and spherical nanoparticles could increase the average Nu number. Besides, the larger Ma was, the larger the free surface velocity of the thermal marangoni convection of nanofluids was, and the convection heat transfer effect could also be enhanced.

     

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