Numerical Analysis On The Flow And Heat Transfer Characteristics Of Cinquefoil Longitudinal Baffle Heat Exchanger

A longitudinal heat exchanger named cinquefoil longitudinal baffle heat exchanger was improved to solve the problem existed in the application of cross-flow heat exchanger. Comparing the flow and heat transfer characteristics of segmental baffle heat exchanger and cinquefoil longitudinal baffle heat exchanger by CFX. A further numerical research about how the different shell s ide parameters influences the heat exchanger performance was carried out, and then studying the condensation in the cinquefoil longitudinal baffle heat exchanger preliminarily.The fluid flows longitudinally along the length direction of heat pipes, but the cross flow characteristic is obvious in the segmental baffle heat exchanger. There are large stagnated flow region which is almost not exists in the cinquefoil longitudinal baffle heat exchanger behind the segmental baffle. In the Reynolds number range, the shell side pressure drop ?p of the two type heat exchanger become larger when the Re is higher. The ?p of cinquefoil longitudinal baffle heat exchanger is 25.89% lower than segmental baffle heat exchanger, and the average convection heat transfer coefficient h is much closer of the two heat exchangers. The comprehensive performance coefficient of cinquefoil baffle heat exchanger is 9.36% higher than segmental baffle heat exchanger in the Re range.According to the simulation result of heat exchanger with different baffle pitch, bot h the ?p and h become larger with the baffle pitch goes smaller. The comprehensive performance coefficient become larger with the baffle pitch goes larger.The simulation results of heat exchanger with three different opening ratio show that both the shell s ide pressure drop and heat transfer coefficient is larger with the higher opening ratio ?, same as the comprehensive performance.All the pressure drop, heat transfer coefficient and comprehensive performance coefficient of cinquefoil baffle heat exchanger goes down when increasing the orifice numbers.Under the shell inlet veloc ity from 5m/s to 20m/s, the average condensation mass flux M?_H2O of the water vapor on the heat pipe surface goes larger with the velocity goes higher.