15-11-2014, 09:22 AM
Abstracts: A heat exchanger is a device in which two fluid streams, one hot and another cold, are brought into ‘thermal contact’ in order to affect transfer of heat from the hot fluid stream to cold. It provides a relatively large area of heat transfer for a given volume of the equipment. The construction also caters for easy cleaning and maintenance of equipment. The shell and tube type of heat exchanger (evaporator) offers unique advantage over other variants in applications like the case for this dissertation work. The enclosed shell can contain fluid (milk) while superheated steam is passed through the spiral tube for heating the milk. The rate of heat transfer depends on the key factors as the material of the tube, the area of exposure (proportional to the diameter), the pitch of the spiral, the number of turns and the total length of the tube besides the differential in the temperatures of the interacting media.