scholarly journals Simulation of Thermomagnetic Convection in a Cavity Using the Lattice Boltzmann Model

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Mahshid Hadavand ◽  
Antonio C. M. Sousa

Thermomagnetic convection in a differentially heated square cavity with an infinitely long third dimension is numerically simulated using the single relaxation time lattice Boltzmann method (LBM). This problem is of considerable interest when dealing with cooling of microelectronic devices, in situations where natural convection does not meet the cooling requirements, and forced convection is not viable due to the difficulties associated with pumping a ferrofluid. Therefore, circulation is achieved by imposing a magnetic field, which is created and controlled by placing a dipole at the bottom of the enclosure. The magnitude of the magnetic force is controlled by changing the electrical current through the dipole. In this study, the effects of combined natural convection and magnetic convection, which is commonly known as “thermomagnetic convection,” are analysed in terms of the flow modes and heat transfer characteristics of a magnetic fluid.

Author(s):  
Mahshid Hadavand ◽  
Aydin Nabovati ◽  
Antonio C. M. Sousa

The application of the single relaxation time lattice Boltzmann method (LBM) is extended to the study of thermomagnetic convection in a differentially heated square cavity with an infinitely long third dimension. The magnetic field is created and controlled by placing a dipole at the bottom of the enclosure. The magnitude of the magnetic force acting on the ferrofluid is controlled by changing the electrical current through the dipole. In this study, the effects of combined natural convection and magnetic convection, which is commonly known as “thermomagnetic convection”, are analysed in what concerns the flow modes and heat transfer characteristics of a magnetic fluid (ferrofluid). This is a situation of considerable interest for cooling micro-electronic devices, when natural convection does not meet the cooling requirements, and forced convection is not viable due to the difficulties associated with pumping a ferrofluid.


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.


2008 ◽  
Vol 29 (5) ◽  
pp. 1469-1480 ◽  
Author(s):  
Christian Huber ◽  
Andrea Parmigiani ◽  
Bastien Chopard ◽  
Michael Manga ◽  
Olivier Bachmann

Author(s):  
KUN QU ◽  
CHANG SHU ◽  
JINSHENG CAI

In this paper, a new flux solver was developed based on a lattice Boltzmann model. Different from solving discrete velocity Boltzmann equation and lattice Boltzmann equation, Euler/Navier-Stokes (NS) equations were solved in this approach, and the flux at the interface was evaluated with a compressible lattice Boltzmann model. This method combined lattice Boltzmann method with finite volume method to solve Euler/NS equations. The proposed approach was validated by some simulations of one-dimensional and multi-dimensional problems.


2007 ◽  
Vol 18 (01) ◽  
pp. 15-24 ◽  
Author(s):  
LAJOS SZALMÁS

We present a new boundary condition in the lattice Boltzmann method to model slip flow along curved boundaries. A requirement is formulated for the distribution functions based on the tunable momentum balance at the walls, which is shown to be equivalent to the constraint on the second moment. Numerical simulation of plane Couette flow in inclined channels and cylindrical Couette flow shows excellent agreement with the analytical results in the nearly continuum regime. Orientation effects on the velocity field are completely avoided.


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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