Combined convection in inclined porous lid-driven enclosures with sinusoidal thermal boundary condition on one wall

Author(s):  
Hakan F. Oztop ◽  
Asaf Varol
1992 ◽  
Vol 15 (4) ◽  
pp. 789-794 ◽  
Author(s):  
G. Ramanaiah ◽  
V. Kumaran

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.


1979 ◽  
Vol 101 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Y. Saito ◽  
N. Nishiwaki ◽  
Y. Ito

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.


2020 ◽  
Vol 399 ◽  
pp. 65-75 ◽  
Author(s):  
Abdul Rahman Mohd Kasim ◽  
Nur Syamilah Arifin ◽  
Syazwani Mohd Zokri ◽  
Mohd Zuki Salleh

The investigation on the interaction between solid and fluid under combined convective flow has been carried out mathematically. The Jeffrey fluid model is taken as the fluid phase and the model is being embedded with the dust particles (solid phase). This two-phase model is constructed by introducing the fluid-particles interaction forces in the momentum equations of the fluid and dust phases, respectively. The natural and forced convections together with the aligned magnetic field are considered on the fluid flow. Also, the Newtonian heating as thermal boundary condition is induced on the vertical stretching sheet. In order to reduce the complexity of the model, the governing equations are transformed from partial differential equation into ordinary differential equation via suitable similarity transformation. The solutions are obtained in terms of velocity and temperature profiles for the fluid and particles phases respectively whereby the Keller-box method is utilized to obtain the desired outcomes. The influences of several significant physical parameters are visualized graphically to clarify the flow and heat transfer characteristic for both phases. The investigation found that the fluid’s velocity is affected by the presence of the dust particles which led to decelerate the fluid transference. The present flow model is able to be compared with the single-phase fluid cases if the fluid-particle interaction parameter is ignored.


Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 246
Author(s):  
Lukasz Pleskacz ◽  
Elzbieta Fornalik-Wajs ◽  
Sebastian Gurgul

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.


Sign in / Sign up

Export Citation Format

Share Document