Regularized lattice Boltzmann model for double-diffusive convection in vertical enclosures with heating and salting from below
Regularized lattice Boltzmann model for double-diffusive convection in vertical enclosures with heating and salting from below
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DOI：
10.1016/j.applthermaleng.2016.04.080
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发表时间：
2016-06
影响因子：
6.4
通讯作者：
Lei Wang;B. Shi;Z. Chai;Xuguang Yang
中科院分区：
文献类型：
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作者：
Lei Wang;B. Shi;Z. Chai;Xuguang Yang
具有垂直温度和浓度梯度的围护结构中的双扩散对流是科学和工程中的重要问题。本文首先提出了温度场或浓度场的正则化晶格Boltzmann模型，然后通过对方形腔内二维rayleigh - b<s:2>纳德对流的数值模拟对该模型进行了验证。最后，利用该模型研究了长径比（即A= H/L， H和L分别为箱体深度和宽度）分别为2.0和4.0的垂直箱体内的双扩散对流。为了提高计算效率，所有模拟都是在使用NVIDIA CUDA的图形处理单元（GPU）上进行的。结果表明：流场涡数、等温线再循环区和等浓度区随着展弦比的增大而增大；在传导扩散主导阶段，平均Nusselt数和Sherwood数基本保持不变，而在对流主导阶段，平均Nusselt数和Sherwood数随瑞利数或浮力比的增加而增加。此外，还发现传热传质率随长径比的增大而减小。
Double-diffusive convection in enclosures with vertical temperature and concentration gradients is an important problem in both science and engineering. In this paper, we first present a regularized lattice Boltzmann model for temperature field or concentration field, and then validate the present model through numerical simulations of two-dimensional (2D) Rayleigh-Bénard convection in a square cavity. Finally, the proposed model is used to study double-diffusive convection in vertical enclosures with aspect ratio (ie, A= H/L with H and L being the enclosure depth and width) equaling 2.0 and 4.0. To improve the computational efficiency, all simulations are performed on the Graphics Processing Unit (GPU) using NVIDIA’s CUDA. The results show that the vortex number of flow field, recirculation zones of isotherms and iso-concentrations increase in aspect ratio. And additionally, the average Nusselt and Sherwood numbers almost keep constant during the conduction and diffusion dominated stage, and then increase with the increase of Rayleigh number or buoyancy ratio during the convection dominated stage. Moreover, it is also found that the heat and mass transfer rates are decreased with the increase of the aspect ratio.