Abstract
Experimental study on heat transfer of natural convection of air which occurs due to the temperature difference between two opposing vertical walls along the direction of gravity in a cube with 50 mm side length is provided. The objective is to investigate the essential aspect of heat transfer in the wide range of Rayleigh number (Ra) by lowering the pressure. The pressure varied from 5.40 kPa (40.5mmHg) to 0.100 MPa (750mmHg). These correspond to 1036 to 356292,in terms of Ra. The obtained experimental results show that the distribution of temperature and Nusselt number (Nu) approach to those of conduction state as the pressure decreases.
