Cross-stream Deployment of Delta Vortex Generators in Finned Tube Arrays for Flow Modification and Capacity Augmentation

Abstract

AbstractFinned tube arrays are extensively used for process heat transfer applications. It is a thermal system that involves gas-to-liquid heat exchange or vice versa. Its thermal capacity can be effectively increased by introducing longitudinal vortex generators in the flow which helps in curtailing the adverse effects of large recirculation regions prevailing in the plain finned tube arrays. Three numerical simulations are conducted to examine the effect of cross-stream translation of toe-out type vortex generators on the tube-wake management and the consequent thermal augmentation. The vortex generators are deployed at a fixed streamwise location to examine the effect of their cross-stream translation. Flow visualization reveals that each tube has a very large recirculation zone in its downstream which essentially results in poor heat transfer coefficients on the affected fin area. A considerate deployment of longitudinal vortex generators, behind the tubes, helps in curtailing the large recirculation zones, thereby producing appreciable augmentation in the heat exchange capacity at same Reynolds number.KeywordsFinned tube arrayVortex generatorsHeat transfer augmentationHeat exchangerWake management