LTNE条件下多孔方腔内Cu-水纳米流体自然对流研究  

Study on natural convection of Cu-water nanofluid in a square porous cavity under LTNE condition

作　　者：刘晨玺 马兵善[1] 王刚[1] LIU Chenxi;MA Bingshan;WANG Gang(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050

出　　处：《甘肃科学学报》2024年第6期137-143,共7页Journal of Gansu Sciences

基　　金：国家自然科学基金项目(11962016)。

摘　　要：采用局部非热平衡假设,对固体骨架分别为玻璃球和泡沫铝的多孔介质方腔内Cu-水纳米流体自然对流进行数值模拟。研究了无量纲容积换热系数、瑞利数、孔隙率和纳米颗粒体积分数对多孔方腔内纳米流体自然对流传热特性的影响。结果表明,当瑞利数较小时,可以用局部热平衡模型代替局部非热平衡模型计算多孔腔体内的自然对流。当瑞利数较大时,对于填充玻璃球的多孔腔体自然对流,孔隙率较大时可以采用局部热平衡模型计算,而对于填充泡沫铝的多孔腔体自然对流应采用局部非热平衡模型计算。填充泡沫铝的腔体内使用Cu-水纳米流体时,总的传热速率并没有明显的变化。对于填充玻璃球的腔体,当瑞利数较小时使用Cu-水纳米流体可以明显增加腔体的传热速率,而当瑞利数较大时填充玻璃球的腔体传热速率随纳米颗粒体积分数的增大而降低。Using the local thermal non-equilibrium assumption,a numerical study is conducted on the natural convection of Cu-water nanofluid in a porous square cavity with solid matrix of glass beads and foam aluminum,respectively.The effects of dimensionless interphase heat transfer coefficient,Rayleigh number,porosity,and nanoparticle volume fraction on the heat transfer characteristics on the natural convection heat transfer characteristics of nanofluid in porous square cavity are investigated.The results show that the local thermal equilibrium model can replace the local thermal non-equilibrium model to calculate the natural convection inside a porous cavity when the Rayleigh number is low.When the Rayleigh number is high,for the natural convection in the porous cavity filled with glass beads,the local thermal equilibrium model can be used to calculate the heat transfer when the porosity is high,while the local thermal non-equilibrium model should be used to calculate the heat transfer for the porous cavity filled with foam aluminum.When Cu-water nanofluid is used in the cavity filled with foam aluminum,the overall heat transfer rate remains unchanged.For the cavity filled with glass beads,the use of Cu-water nanofluid can significantly increase the heat transfer rate when the Rayleigh number is low,while the heat transfer rate of the cavity filled with glass beads decreases with the increase of the volume fraction of nanoparticles when the Rayleigh number is high.

关 键 词：纳米流体 多孔介质 自然对流 局部非热平衡 

分 类 号：TK124[动力工程及工程热物理—工程热物理]