Computational fluid dynamics analysis of a cross flow heat exchanger

Abstract

The paper presents the computational fluid dynamics analysis of a cross flow heat exchanger of hot Freon Fluid tube submerged in cold  water domain. The simulation procedures were done for the two inlet velocities of the hot fluid at 0.015m/s and 0.035m/s; for a constant  flow velocity of 0.02m/s for the cold water. The result of the temperature distribution showed a decrease from 305 to 301.69K and  305 to 302.44; and an increase from 300 to 301.75 and 300to302.45 for the hot Freon and cold water fluids respectively. The logarithmic  mean temperature difference (LMTD) value for the two inlet velocities of hot Freon fluid were evaluated to be 2.71K and 2.68K;  consequently, the required operating average temperature difference of the flow system for the two fluids was established to be 2.70K;  while the effectiveness was determined as 89%.Further, the analysis revealed a constant pressure distribution across the water plate,  while the Freon fluid increased from 1 to 1.77atm across the tube length. The velocity distribution showed that the cold water velocity  increased rapidly around the horizontal and angled orientations of the Freon tube from 0.02 to 0.15m/s; while that of the hot Freon fluid  remained constant across the tube length. This change in velocity was attributed to the high rate of heat exchange rate at those sections  of the Freon tube. The findings from this study will be used to enhance the design and performance evaluation of heat exchangers to  meet future technological demands.