scholarly journals Lattice Boltzmann Simulation of Airflow and Mixed Convection in a General Ward of Hospital

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Taasnim Ahmed Himika ◽  
Md. Farhad Hasan ◽  
Md. Mamun Molla
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Lattice Boltzmann ◽  
Average Rate ◽  
Reynolds Numbers ◽  
General Ward ◽  
Convection Flow ◽  
Indoor Airflow ◽  
Lattice Boltzmann Simulation ◽  
Boltzmann Method

In the present investigation the airflow and heat transfer for mixed convection have been simulated for a model general ward of hospital with six beds and partitions using the Lattice Boltzmann Method (LBM). Three different Reynolds numbers 100, 250, and 350 have been considered. Bounce-back condition has been applied at the wall. Results have been represented in three different case studies and the changes have been discussed in terms of streamlines and isotherms. Code validation has also been included before going through the simulation process and it shows good agreement with previously published papers when the comparison is made on average Nusselt number. Results show that the pattern of indoor airflow is varied in each and every case study due to the effect of mixed convection flow and placement of partition. In addition, the changes in average rate of heat transfer indicate that patients closer to inlet get the most air and feel better and if any patient does not need much air, he or she should be kept near the outlet to avoid temperature related complications.

Lattice Boltzmann Simulation of Airflow and Heat Transfer in a Model Ward of a Hospital

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Md. Farhad Hasan ◽  
Taasnim Ahmed Himika ◽  
Md. Mamun Molla
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Lattice Boltzmann ◽  
Average Rate ◽  
Reynolds Numbers ◽  
Hospital Ward ◽  
Computational Technique ◽  
Maximum Heat ◽  
Nusselt Numbers ◽  
Lattice Boltzmann Simulation

In this research, a very popular alternative computational technique, the lattice Boltzmann method (LBM), has been used to simulate the indoor airflow and heat transfer in a model hospital ward. Different Reynolds numbers have been used to study the airflow pattern. Boundary conditions for velocity and temperature have also been discussed in detail. Several tests have been conducted for code validation. LBM is demonstrated through simulation in forced convection inside hospital ward with six beds for two different situations: ward without partition and ward with partition. Changes in average rate of heat transfer in terms of average Nusselt numbers have also been recorded for those situations. Average Nusselt numbers were found to differ for different cases. In terms of airflow, it has been found that, for various Reynolds numbers, airflow changes its pattern and leads to few recirculations for relatively higher Reynolds number but remains steady for low Reynolds number. It was observed that partition narrowed the channel for airflow and once the air overcame this barrier, it gets free space and recirculation appears more. For higher Reynolds number, the average rate of heat transfer increases and patients near the recirculation zone release maximum heat and will feel more comfortable.

scholarly journals Lattice Boltzmann simulation of two-sided lid-driven flow in deep cavities

2015 ◽  
pp. 157-168
Author(s):  
Natasa Lukic ◽  
Predrag Tekic ◽  
Jelena Radjenovic ◽  
Ivana Sijacki
Keyword(s):  
Aspect Ratio ◽  
Flow Pattern ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Critical Aspect ◽  
Symmetric Flow ◽  
Primary Vortex ◽  
Lattice Boltzmann Simulation ◽  
Boltzmann Method ◽  
Deep Cavities

The present study is concerned with two-sided lid-driven incompressible flow in rectangular, deep cavities applying lattice Boltzmann method. After validating the code for the square cavity, solutions for cavities with an aspect ratio 1.5 and 4 were obtained for the Reynolds numbers of 100, 400, 1000 and 3200. The influence of the Reynolds number and aspect ratio on the flow pattern and on the characteristics of vortices inside the cavity was studied. Symmetric flow pattern was obtained for all investigated cases. The middle of the cavity is mostly influenced by the increase in the aspect ratio. Critical aspect ratio, at which the birth of a primary vortex in the middle of the cavity takes place, was determined to be between 2.7 and 2.725.

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.

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.

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.

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.

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.

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