Numerical Simulation of Unsteady Heat Transfer in a Half-Moon Shape Enclosure with Variable Thermal Boundary Condition for Different Nanofluids

2014 ◽  
Vol 65 (3) ◽  
pp. 282-301 ◽  
Author(s):  
M. M. Rahman ◽  
S. Saha ◽  
S. Mojumder ◽  
S. Mekhilef ◽  
R. Saidur
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Boundary Condition ◽  
Thermal Boundary Condition ◽  
Unsteady Heat Transfer

Numerical Simulation of Human Thermal Comfort with Different Thermal Boundary Conditions in Buildings

2014 ◽  
Vol 522-524 ◽  
pp. 1707-1712 ◽  
Author(s):  
Qing Long Peng ◽  
Zhao Hui Qi ◽  
Xia Gan ◽  
Chao Li
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Boundary Condition ◽  
Thermal Comfort ◽  
Human Body ◽  
Thermal Boundary Condition ◽  
Human Thermal Comfort ◽  
The Third ◽  
Thermal Boundary Conditions ◽  
Body Heat

How to use numerical simulation method to analyze human body heat transfer and human thermal comfort is introduced in this paper systematically. Under the same working conditions, numerical simulation of human body heat transfer has been finished based on three thermal boundary conditions, and then the results are compared. The results show that the third thermal boundary condition is better than the first and the second one, which have some problems in simulation and are not good at reflecting the fact on thermal comfort of human body. The third thermal boundary condition which is made to adapt the surrounding flow field automatically can get a more accurate result on calculating the heat transfer of different parts on human body and reflect hot or cool feeling preferably, which proves that the method put forward in this article to research the human body comfort is feasible.

scholarly journals Darcy-Brinkman free convection about a wedge and a cone subjected to a mixed thermal boundary condition

1992 ◽  
Vol 15 (4) ◽  
pp. 789-794 ◽  
Author(s):  
G. Ramanaiah ◽  
V. Kumaran
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Flux ◽  
Porous Medium ◽  
Heat Transfer Coefficient ◽  
Free Convection ◽  
Transformation Group ◽  
Darcy Number ◽  
Thermal Boundary Condition ◽  
High Porosity

The Darcy-Brinkman free convection near a wedge and a cone in a porous medium with high porosity has been considered. The surfaces are subjected to a mixed thermal boundary condition characterized by a parameterm;m=0,1,∞correspond to the cases of prescribed temperature, prescribed heat flux and prescribed heat transfer coefficient respectively. It is shown that the solutions for differentmare dependent and a transformation group has been found, through which one can get solution for anymprovided solution for a particular value ofmis known. The effects of Darcy number on skin friction and rate of heat transfer are analyzed.

An Investigation of Local Heat Transfer during Grinding Process—Effects of Porosity of Grinding Wheel

1979 ◽  
Vol 101 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Y. Saito ◽  
N. Nishiwaki ◽  
Y. Ito
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Thermal Boundary Condition ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Workpiece Surface

The thermal boundary condition around the workpiece surface is one of important factors to analyze the thermal deformation of a workpiece, which is in close relation to the machining, accuracy of grinding. The heat dissipation from the workpiece surface which is influenced by the flow pattern, may govern this thermal boundary condition. In consequence, it is necessary to clarify the convection heat transfer coefficient and the flow pattern of air and/or grinding fluid around surroundings of a rotating grinding wheel and of a workpiece. Here experiments were carried out in a surface grinding process to measure the flow velocity, wall pressure and local heat transfer by changing the porosity of the grinding wheel. The air blowing out from the grinding wheel which is effected by the porosity may be considered to have large influences on the local heat transfer coefficient, which is found to be neither symmetric nor uniform over the workpiece surface.

scholarly journals Asymmetrical Thermal Boundary Condition Influence on the Flow Structure and Heat Transfer Performance of Paramagnetic Fluid-Forced Convection in the Strong Magnetic Field

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 246
Author(s):  
Lukasz Pleskacz ◽  
Elzbieta Fornalik-Wajs ◽  
Sebastian Gurgul
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Enhancement ◽  
Strong Magnetic Field ◽  
Flow Structure ◽  
Thermal Boundary Condition ◽  
Solid Particles ◽  
Transfer Enhancement ◽  
Dimensionless Numbers

Continuous interest in space journeys opens the research fields, which might be useful in non-terrestrial conditions. Due to the lack of the gravitational force, there will be a need to force the flow for mixing or heat transfer. Strong magnetic field offers the conditions, which can help to obtain the flow. In light of this origin, presented paper discusses the dually modified Graetz-Brinkman problem. The modifications were related to the presence of the magnetic field influencing the flow and asymmetrical thermal boundary condition. Dimensionless numerical analysis was performed, and two dimensionless numbers (magnetic Grashof number and magnetic Richardson number) were defined for paramagnetic fluid flow. The results revealed the heat transfer enhancement due to the strong magnetic field influence accompanied by possible but not essential flow structure modifications. On the other hand, the flow structure changes can be utilized to prevent the solid particles’ sedimentation. The explanation of the heat transfer enhancement including energy budget and vorticity distribution was presented.

Three Dimensional Numerical Analysis of Laminar Slip-Flow Heat Transfer in Rectangular Microchannels

2008 ◽  
Author(s):  
H. D. Madhawa Hettiarachchi ◽  
Mihajlo Golubovic ◽  
William M. Worek
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Temperature Jump ◽  
Slip Flow ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Thermal Boundary Condition ◽  
Navier Stokes ◽  
Constant Wall Temperature ◽  
Rectangular Microchannels

Slip-flow and heat transfer in rectangular microchannels are studied numerically for constant wall temperature (T) and constant wall heat flux (H2) boundary conditions under thermally developing flow. Navier-Stokes and energy equations with velocity slip and temperature jump at the boundary are solved using finite volume method in a three dimensional cartesian coordinate system. A modified convection-diffusion coefficient at the wall-fluid interface is defined to incorporate the temperature-jump boundary condition. Validity of the numerical simulation procedure is stabilized. The effect of rarefaction on heat transfer in the entrance region is analyzed in detail. The velocity slip has an increasing effect on the Nusselt (Nu) number whereas temperature jump has a decreasing effect, and the combined effect could result increase or decrease in the Nu number. For the range of parameters considered, there could be high as 15% increase or low as 50% decrease in fully developed Nu is plausible for T thermal boundary condition while it could be high as 20% or low as 35% for H2 thermal boundary condition.

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