An Experimental Study of Natural Convection in Porous Media Heated from below

Authors

  • P. Nagaraju Department of Physics, Vijaya College, Bangalore-560 004

DOI:

https://doi.org/10.12723/mjs.19.3

Abstract

The present experimental study is carried out using a rectangular cavity packed with porous medium such as iron balls or glass balls of different diameters and hence different porosity. The lower plate is maintained at a uniform temperature Th, which is higher than the temperature Tc of upper plate. The experiment is performed for both closed and open systems in vertical as well as horizontal orientation of the test box. When ( Th - Tc ) is increased beyond a certain value, convective motion takes place in the fluid. The results of the experiment indicate that a porous medium can transport more energy than a saturated fluid alone if the porous matrix is highly permeable and thermal conductivity of solid particles is greater than that of fluid. This experiment also shows that convective effect is more in open system i.e., free boundary at the top. It is also observed that the time taken to reach the thermal steady state is less in the horizontal orientation as compared to the vertical orientation. In this study, the relationship between Rayleigh and Nusselt numbers has been investigated in addition to the expected temperature profile. It is found that the magnitude of temperature for iron balls is about 10% more as compared to glass balls and about 18% higher for vertical orientation as compared to horizontal orientation.

References

D.A. Nield and A. Bejan. Convection in Porous Media, 2nd ed, Springer, New York, 1998

D.B. Ingham and I. Pop (Eds)., Transport Phenomena in Porous Media, Pergamon Press, Oxford, 1998.

Vafai. K., Handbook of Porous Media. Marcel Dekker, New York 2000.

Larkin B. K, Churchill S.W., Heat transfer by radiation through Porous insulations, AIChE Journal 5 467-474, 1959.

Pop. I, Ingham D.B., Convective heat transfer, Mathematical and computational modeling of viscous fluids and porous media, Pergamon, Oxford, 2001.

M. N. Ozisik., Heat transfer, McGraw Hill, 1986

Nobuhiro Seki, S. Fukusako and Inaba., Heat transfer in a confined rectangular cavity packed with porous media. Int J. Heat transfer and Mass transfer, 21-11 (1978), 985

H. Inaba, N. Seki., A study on transient characteristics of Natural Convective Heat transfer in a confined rectangular cavity packed with porous media, Bulletin of JSME, Vol 26, No. 222, 1983.

S. Yagi and D. Kunii., Studies on heat transfer in packed beds, Int Dev, Heat transfer, 4, 750, 1962.

Published

2021-08-26