HEAT TRANSFER BETWEEN HUMID AIR AND A HORIZONTAL PLATE AT 'SUBFREEZING TEMPERATURE WITH FROST FORMATION

Abstract

This dissertation deals with experimental investigation of the effects of temperature, specific humidity and velocity of humid air on frost formation over a horizontal flat evaporator plate, held at varying sub-freezing temperatures. A set-up was fabricated and installed to conduct the above mentioned investigations. The results so obtained are compared with those obtained by other investigators. Values of quasi-steady state overall heat transfer coefficient (U) between humid air and plate surface with frost in between, has also been compared. 'U has been found to be increasing with increase in air temperature, specific humidity and velocity, but it decreases with increase of plate temperature. Experimentally determined values of convective mass transfer coefficient 'hi' under frosting condition have also been presented.