Geometric optimization for thermal-hydraulic performance of dimpled enhanced tubes for single phase flow

Enhanced surfaces have larger heat transfer surface area and offer increased turbulence level hence allowing higher heat exchange performance. In this study, numerical simulations are conducted to simulate geometric design optimization of enhanced tubes for optimal thermal-hydraulic performance. The simulations are validated with experimental data. Two and three dimensional steady incompressible turbulent flow in dimpled enhanced tube is numerically studied using realizable k-ϵ method. The pressure-velocity coupling is solved by Semi-Implicit Method for Pressure Linked Equations Consistent (SIMPLEC) algorithm. Results show that dimples on tube surface present high heat transfer performance. Compared to staggered configuration, the in-line dimples arrangement provided better overall heat exchange characteristics. The geometric parameters like dimple shape, depth, pitch and starts are found to have significant effects on overall heat exchange performance while the dimple diameter has insignificant effect on thermal performance.