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MHD free convection-radiation interaction in a porous medium - part II: soret/dufour effects

Vasu B., Gorla Rama Subba Reddy, Murthy P. V. S. N., Prasad V. R., Beg O. A., Siddiqa S.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 2

157--175

EN

This paper is focused on the study of two dimensional steady magnetohydrodynamics heat and mass transfer by laminar free convection from a radiative horizontal circular cylinder in a non-Darcy porous medium by taking into account of the Soret/Dufour effects. The boundary layer equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, stable Keller–Box finite-difference scheme. Numerical results are obtained for the velocity, temperature and concentration distributions, as well as the local skin friction, Nusselt number and Sherwood number for several values of the parameters, namely the buoyancy ratio parameter, Prandtl number, Forchheimer number, magnetohydrodynamic body force parameter, Soret and Dufour numbers. The dependency of the thermophysical properties has been discussed on the parameters and shown graphically. Increasing the Forchheimer inertial drag parameter reduces velocity but elevates temperature and concentration. Increasing the Soret number and simultaneously reducing the Dufour number greatly boosts the local heat transfer rate at the cylinder surface. A comparative study of the previously published and present results in a limiting sense is made and an excellent agreement is found between the results.

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MHD free convection-radiation interaction in a porous medium - part I: numerical investigation

Vasu B., Gorla R. S. R., Murthy P. V. S. N., Prasad V. R., Bég O. Anwar, Siddiqa S.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 1

198--218

EN

A numerical investigation of two dimensional steady magnetohydrodynamics heat and mass transfer by laminar free convection from a radiative horizontal circular cylinder in a non-Darcy porous medium is presented by taking into account the Soret/Dufour effects. The boundary layer conservation equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, stable Keller–Box finite-difference scheme. We use simple central difference derivatives and averages at the mid points of net rectangles to get finite difference equations with a second order truncation error. We have conducted a grid sensitivity and time calculation of the solution execution. Numerical results are obtained for the velocity, temperature and concentration distributions, as well as the local skin friction, Nusselt number and Sherwood number for several values of the parameters. The dependency of the thermophysical properties has been discussed on the parameters and shown graphically. The Darcy number accelerates the flow due to a corresponding rise in permeability of the regime and concomitant decrease in Darcian impedance. A comparative study between the previously published and present results in a limiting sense is found in an excellent agreement.

3

Evaluation of pre-jamming indication parameter during blind backfilling technique

Panda S., Pal S. K., Murthy P. V. S. N.

Journal of Sustainable Mining

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2016

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Vol. 15, iss. 3

100--107

EN

Hydraulic blind backfilling is used to reduce subsidence problems above old underground water-logged coal mines. This paper describes experimental research on a fully transparent model of a straight underground mine gallery. An automatic data acquisition systemwas installed in the model to continuously record the sand and water flowrates along with the inlet pressure of the slurry near the model's inlet. Pressure signature graphs and pressure loss curves with bed advancement under different flow conditions are examined. Pressure signature analyses for various flowrates and sand slurry concentrations are conducted to evaluate a pre-jamming indication parameter, which could be used to indicate the arrival of the final stage of filling.

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Mixed convection heat and mass transfer in a doubly stratified non-Darcy porous medium

Murthy P. V. S. N., Mukherjee S., Krishna P. V. S. S. S. R., Srinivasacharya D.

International Journal of Applied Mechanics and Engineering

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2007

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Vol. 12, no 1

109-123

EN

The mixed convection heat and mass transfer from a vertical surface embedded in a doubly stratified nonDarcy porous medium have been analyzed. The wall temperature and concentration are constant and the medium is linearly stratified with respect to both temperature and concentration. The external flow is assumed to be uniform. A series approximation is made for both temperature and concentration in terms of the stratification parameter and the solution is presented in both the aiding and opposing flow cases. The flow, temperature and concentration fields are effected by complex interactions among the diffusion ratio Le and buoyancy ratio N and stratification ratio Sr in addition to the flow driving mixed convection parameter Ra/Pe The effect of double stratification of the medium on non-dimensional heat and mass transfer coefficients is discussed.