Lattice Boltzmann Simulation of Flow and Heat Transfer Characteristics in a Symmetrically Bifurcated Microchannel

Author(s):  
Keqiang Xing ◽  
Yong Tao

The lattice Boltzmann method (LBM) as a relatively new numerical scheme has recently achieved considerable success in simulating fluid flows and associated transport phenomena. However, application of this method to heat transfer problems has been at a stage of infancy. In this work, a thermal lattice Boltzmann model is employed to simulate a two-dimensional, steady flow in a symmetric bifurcation under constant temperature and constant heat flux boundary conditions. The bifurcation effects on the heat transfer and fluid flow are investigated and comparisons are made with the straight tube. Also, different bifurcation angles are simulated and the results are compared with the work of the other researchers.

2005 ◽  
Author(s):  
K. Q. Xing ◽  
Y.-X. Tao

The lattice Boltzmann method (LBM) originates from the discrete kinetic theory and has been applied for simulation of various kinds of fluid flows under different conditions. In this paper, a passive-scalar-based thermal lattice Boltzmann model is employed to simulate the steady flow in a symmetric bifurcation channel under constant wall heat flux boundary conditions. The bifurcation effects on the heat transfer and fluid flow are thoroughly investigated under different Reynolds numbers, wall heat fluxes and bifurcation angles. The results are compared with the commercial software output. A useful discussion about how to transfer from lattice units to actual physical units is also presented.


Author(s):  
Nishitha Thummala ◽  
Dimitrios V. Papavassiliou

This work presents a Lagrangian approach to simulate convective heat transfer in small scales. The fully developed flow field, simulated by a Lattice Boltzmann Method, is combined with Lagrangian tracking of thermal markers to determine the behavior of an instantaneous scalar line source located at the wall of a channel. The resulting probability density functions are used to calculate the behavior of continuous line sources of heat at the wall of the channel, as well as the temperature for the case of constant temperature or constant heat flux from the wall. This method is resourceful in terms of computational efficiency, in that it can be used to simulate various thermal boundary conditions and Prandtl number fluids with a single flow field resulting from a Lattice Boltzmann simulation.


Author(s):  
Minglei Shan ◽  
Yu Yang ◽  
Hao Peng ◽  
Qingbang Han ◽  
Changping Zhu

Understanding the dynamic characteristic of the cavitation bubble near a solid wall is a fundamental issue for the bubble collapse application and prevention. In the present work, an improved three-dimensional multi-relaxation-time pseudopotential lattice Boltzmann model is adopted to investigate the cavitation bubble collapse near the solid wall. With respect to thermodynamic consistency, Laplace law verification, the three-dimensional pseudopotential multi-relaxation-time lattice Boltzmann model is investigated. By the theoretical analysis, it is proved that the model can be regarded as a solver of the Rayleigh–Plesset equation, and confirmed by comparing the results of the lattice Boltzmann simulation and the Rayleigh–Plesset equation calculation for the case of cavitation bubble collapse in the infinite medium field. The bubble collapse near the solid wall is modeled using the improved pseudopotential multi-relaxation-time lattice Boltzmann model. We find the lattice Boltzmann simulation and the experimental results have the same dynamic process by comparing the bubble profiles evolution. Form the pressure field and the velocity field evolution it is found that the tapered higher pressure region formed near the top of the bubble is a crucial driving force inducing the bubble collapse. This exploratory research demonstrates that the lattice Boltzmann method is an alternative tool for the study of the interaction between collapsing cavitation bubble and matter.


2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
You-Sheng Xu ◽  
Rui-Min Wang ◽  
Guo-Neng Li ◽  
You-Qu Zheng

A lattice Boltzmann model of the uniform velocity, driven convective thermal conductivity in a porous cavity is studied. The Darcy, Richardson, and Reynolds numbers are shown to have a significant influence on the heat transfer behavior and the horizontal velocity of the flow field, while the porosity has little influence on either. The model is validated by the average Nusselt number at different Reynolds numbers, and the numerical results are in good agreement with available published data.


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