EXPERIMENTAL INVESTIGATION OF THE EFFECT OF LENGTH OF WIRE-COIL INSERTS ON THE PERFORMANCE OF A THREE-PASS FINNED TUBE HEAT EXCHANGER
Heat transfer enhancement of finned tube heat exchangers is a hot topic of research in the domain of heat transfer owing to its numerous engineering applications including automobile radiator, economizers, and air heaters. Passive heat transfer augmentation techniques block the primary flow and generate more turbulent secondary flow, generally by adding additional devices or inserts into the flow channel, thereby increasing the heat transfer coefficient of the system. Moreover, this method requires no external power for its operation. Hence, in the two broad classifications of heat transfer enhancement techniques, passive techniques have a definite edge over active methods, which need extra power for its operation. The simple manufacturing procedure of wire coil inserts and its easiness in installation to any existing heat exchanger made it a promising passive heat transfer augmentation technique. This study experimentally investigated the effectiveness of full-length and truncated wire coils for a three-pass finned tube heat exchanger at various flow rates. The results showed that truncated wire coils have better heat transfer enhancement capability owing to reduced pumping losses.