Lattice Boltzmann Simulation of Flow and Heat Transfer Characteristics in a Symmetric Bifurcation

2005 ◽  
Author(s):  
K. Q. Xing ◽  
Y.-X. Tao
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann ◽  
Passive Scalar ◽  
Heat Fluxes ◽  
Lattice Boltzmann Model ◽  
Lattice Boltzmann Simulation ◽  
Flux Boundary Conditions ◽  
Constant Wall Heat Flux ◽  
Boltzmann Method ◽  
Thermal Lattice Boltzmann

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.

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

2004 ◽  
Author(s):  
Keqiang Xing ◽  
Yong Tao
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann ◽  
Constant Heat Flux ◽  
Lattice Boltzmann Model ◽  
Straight Tube ◽  
Lattice Boltzmann Simulation ◽  
Flux Boundary Conditions ◽  
Boltzmann Method ◽  
Thermal Lattice Boltzmann ◽  
Transfer Problems

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.

Modeling of collapsing cavitation bubble near solid wall by 3D pseudopotential multi-relaxation-time lattice Boltzmann method

2017 ◽  
Vol 232 (3) ◽  
pp. 445-456 ◽  
Author(s):  
Minglei Shan ◽  
Yu Yang ◽  
Hao Peng ◽  
Qingbang Han ◽  
Changping Zhu
Keyword(s):  
Relaxation Time ◽  
Lattice Boltzmann ◽  
Cavitation Bubble ◽  
Solid Wall ◽  
Three Dimensional ◽  
Lattice Boltzmann Model ◽  
Bubble Collapse ◽  
Lattice Boltzmann Simulation ◽  
Boltzmann Method ◽  
Boltzmann Model

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.

Simulation of Heat Transfer With LBM and Lagrangian Methods for Microfluidic Applications

2005 ◽  
Author(s):  
Nishitha Thummala ◽  
Dimitrios V. Papavassiliou
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Lattice Boltzmann ◽  
Constant Heat Flux ◽  
Fully Developed Flow ◽  
Thermal Boundary Conditions ◽  
Lattice Boltzmann Simulation ◽  
Lagrangian Tracking ◽  
Boltzmann Method ◽  
Single Flow

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.

scholarly journals Numerical Simulation of Driven Convective Heat Transfer Based Lattice Boltzmann Method in a Porous Cavity

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
You-Sheng Xu ◽  
Rui-Min Wang ◽  
Guo-Neng Li ◽  
You-Qu Zheng
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Lattice Boltzmann Model ◽  
Published Data ◽  
Porous Cavity ◽  
Convective Thermal ◽  
Transfer Behavior ◽  
Boltzmann Method ◽  
Boltzmann Model

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.

scholarly journals High-resolution simulation of film cooling with blowing ratio and inclination angle effects based on hybrid thermal lattice Boltzmann method

2021 ◽  
pp. 286-286
Author(s):  
Yanqin Shangguan ◽  
Xian Wang ◽  
Fei Cao ◽  
Yandan Zhu
Keyword(s):  
Heat Transfer ◽  
High Resolution ◽  
Inclination Angle ◽  
Coherent Structure ◽  
Lattice Boltzmann ◽  
Film Cooling ◽  
Blowing Ratio ◽  
Inclination Angles ◽  
Boltzmann Method ◽  
Thermal Lattice Boltzmann

A series of high-resolution simulations on film cooling with varying blowing ratios and inclination angles are carried out by using in-house code based on hybrid thermal lattice Boltzmann method. Three blowing ratios ranging from 0.2 to 0.8 and four inclination angles from 15? to 60? are chosen for the simulations. The evolutionary mechanism of coherent structure in three domains of film-covering region is studied from the view of space and time. Besides, the influencing mechanism of blowing ratio and inclination angle on flow and heat-transfer features of film cooling is uncovered. Results show that hairpin vortex, hairpin packet and quasi-stream-wise vortex appearing in rotating domain play a key role in heat-transfer process of film cooling. The strong ejection, sweep and vortex rotation resulted from these vortices enhance the convective heat transfer. It is also found that the size of coherent structure varies significantly with blowing ratio and its integral form shows a strong dependence on inclination angle. Moreover, inclination angle of coolant jet has a significant impact on turbulence fluctuation intensity. The influence of blowing ratio on the attachment of coolant film and film-cooling performance is more obvious than that of inclination angle. It is believed that all of these are related closely to the variation of stream-wise and wall-normal jet velocity in the case of various blowing ratios and inclination angles.

Lattice Boltzmann Simulation on Natural Convection Heat Transfer for Phase-Change with Heterogeneously Porous Medium

2011 ◽  
Vol 322 ◽  
pp. 61-67 ◽  
Author(s):  
Jiu Gu Shao ◽  
Yang Liu ◽  
You Sheng Xu
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Phase Change ◽  
Lattice Boltzmann ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Lattice Boltzmann Simulation ◽  
Boltzmann Method

The problem of the natural convection heat transfer for phase-change in a square filled with heterogeneously porous medium is solved by lattice Boltzmann method. The lattice Boltzmann equation is governed by the heat conduction equation combined with enthalpy formation. The velocity of liquid part is fully coupled with the temperature distribution through relaxation time. It is found that the high Ra number has significantly impact on the heat transfer and convection, but the low Ra number has little influence on the natural convection. The porosity of the middle porous medium is nothing to do with the heat transfer and convection. The result is of great importance to engineering interest and also provides a new solution to phase transition.

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