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Enhancement of turbulent airflow and heat transfer through a rectangular microchannel with different types of baffles

Saha Sandip, Raut Santanu, Das Apurba Narayan

Journal of Applied Mathematics and Computational Mechanics

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2021

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Vol. 20, nr 3

41--52

EN

The objective of this work is to discuss the turbulent air hydro-thermal phenomena over a rectangular microchannel with different types of baffle (rectangular, triangular, and trapezoidal) mounted on both the walls of the microchannel. The finite volume method with the second order upwind scheme has been utilized to discretize the governing equations and to study the turbulent airflow characteristics; the SST k-ꞷ turbulence model has been adopted. For nine different cases, the different characteristics of fluid flow phenomena and thermal behaviour with the variations in the Reynolds number ranging from [5,000-25,000] and for three different values of inter baffle spacing have been studied in this manuscript. Due to the presence of baffle, it is revealed that the vortex arises on the upper wall and the thermal phenomena enhances with the decrease in inter baffle spacing.

2

Variable viscosity and thermal conductivity effects on heat transfer by natural convection from a cone and a wedge in porous media

Hassanien I. A., Essawy A. H., Moursy N. M.

Archives of Mechanics

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2003

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Vol. 55, nr 4

345-356

EN

The problem of steady, laminar heat transfer by natural convection flow over a vertical cone a wedge embedded in a uniform porous medium with variable viscosity and thermal conductivity is investigated. The transformed governing equations are solved numerically by using a finite difference scheme. The obtained results are compared with earlier papers on special cases of the problem and are found to be in excellent agreement. The influence of porous medium inertia effect, viscosity wariation parameter ... and thermal conductivity variation parameter ... on the fluid velocity and temperature is discussed. Including the porous medium inertia effect or viscosity variation parameter in the mathematical model is predicted to reduce the local Nusselt number. Furthermore, the local Nusselt number increases in the presence of thermal conductivity variation parameter.

3

Buoyancy effects in boundary layers on a continuously moving vertical surface with a parallel free stream

Takhar H. S., Kumari M., Nath G.

Archives of Mechanics

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2001

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Vol. 53, nr 2

151-166

EN

An analysis is performed to study the effect of the buoyancy force on the flow and heat transfer characteristics in a viscous fluid over a heated vertical continuously moving surface with a parallel free stream. The buoyancy force varies with the streamwise distance ... and hence introduces nonsimilarity in the flow field. Both the constant wall temperature and constant heat flux conditions are included in the analysis. The partial differential equations governing the flow are solved numerically. Closed form solutions are obtained when the wall and free stream velocities are equal and there is no buoyancy force. Also the correlation equations for the local Nusselt number are developed. It is found that for opposing flow or for an upstream moving wall, the solution does not exist beyond a certain value of the buoyancy parameter or the ratio of wall and free stream velocities.