1987 Volume 12 Issue 35 Pages 61-71
This paper presents an experimental study on the characteristics of natural convection and radiation heat transfer in a rectangular parallelepiped air space, which is enclosed by two opposite heated and cooled vertical walls and the other adiabatic walls and is separated by a partition plate. The heated and cooled walls are kept under uniform temperature, and the emissivities of them and the partition surfaces are changed from about 0.1 to 0.9. The Rayleigh number based on the temperature difference between the partition and air and the height of the partition ranges 3×10^7 to 10^8. The grade of temperature stratification of air, distributions of temperature, heat flux density and heat transfer coefficient along the height of the partition, and the effect of thermal radiation upon them are clarified. The data on the average heat transfer coefficient can be correlated by the equation for an isolated single plate with uniform temperature, if the air temperature at the upstream end and the wall temperature at the mid height are taken as respective representative ones. Also is shown a procedure to predict air temperature distribution and heat flow rate through the partition for given values of heated and cooled wall temperature by using experimental equations obtained in the present study.
