A new mesoscopic scale timestep adjustable non-dimensional lattice Boltzmann method for melting and solidification heat transfer

Author(s):  
Yan Su ◽  
Jane H. Davidson
2013 ◽  
Vol 24 (09) ◽  
pp. 1350060 ◽  
Author(s):  
M. NAZARI ◽  
M. H. KAYHANI ◽  
R. MOHEBBI

The main goal of the present study is to investigate the heat transfer enhancement in a channel partially filled with an anisotropic porous block (Porous Foam) using the lattice Boltzmann method (LBM). Combined pore level simulation of flow and heat transfer is performed for a 2D channel which is partially filled with square obstacles in both ordered and random arrangements by LBM which is not studied completely in the literature. The effect of the Reynolds number, different arrangements of obstacles, blockage ratio and porosity on the velocity and temperature profiles inside the porous region are studied. The local and averaged Nusselt numbers on the channel walls along with the respective confidence interval and comparison between results of regular and random arrangements are presented for the first time. For constant porosity and block size, the maximum value of averaged Nusselt number in the porous block is obtained in the case of random arrangement of obstacles. Also, by decreasing the porosity, the value of averaged Nusselt number is increased. Heat transfer to the working fluids increases significantly by increasing the blockage ratio. Several blockage ratios with different arrangements are checked to obtain a correlation for the Nusselt number.


2015 ◽  
Vol 25 (5) ◽  
pp. 1214-1230 ◽  
Author(s):  
Tao Sun ◽  
Weizhong Li ◽  
Bo Dong

Purpose – The purpose of this paper is to test the feasibility of lattice Boltzmann method (LBM) for numerical simulation of nucleate boiling and transition boiling. In addition, the processes of nucleate and transition boiling on vertical wall are simulated. The heat transfer mechanism is discussed based on the evolution of temperature field. Design/methodology/approach – In this paper, nucleate boiling and transition boiling are numerically investigated by LBM. A lattice Boltzmann (LB) multiphase model combining with a LB thermal model is used to predict the phase-change process. Findings – Numerical results are in good agreement with existing experimental results. Numerical results confirm the feasibility of the hybrid LBM for direct simulations of nucleate and transition boiling. The data exhibit correct parametric dependencies of bubble departure diameter compared with experimental correlation and relevant references. Research limitations/implications – All the simulations are performed in two-dimensions in this paper. In the future work, the boiling process will be simulated in three-dimensional. Practical implications – This study demonstrated a potential model that can be applied to the investigation of phase change heat transfer, which is one of the effective techniques for enhance the heat transfer in engineering. The numerical results can be considered as a basic work or a reference for generalizing LB method in the practical application about nucleate boiling and transition boiling. Originality/value – The hybrid LBM is first used for simulation of nucleate and transition boiling on vertical surface. Heat transfer mechanism during boiling is discussed based on the numerical results.


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