A proposed method for enhancing the thermal characteristics of bio-inspired microtextured surfaces for energy sector applications

Abstract The research involves generation of textured surfaces using micro-wire electro discharge machining (µ-WEDM) for controlling boundary layers, drag force and heat transfer during fluid flow over the textured surfaces. Numerical analysis of the drag experienced by air, flowing over the microtextured surfaces, is initially carried out using a Large Eddy Simulation (LES) open-source code, Hydro3D, by simulating turbulent flow over the textured surfaces. This is then followed by the manufacture of four microtexture geometries on stainless steel specimens via µ-WEDM and their characterisation using a 3D optical profiler. Velocity profile experiments are then carried out on the micro-geometries at different angles of action against the air flow direction to analyse drag reduction and boundary layer thickness. And finally, heat transfer experiments are carried out in a condensation chamber to evaluate surface temperature differential ( ΔT s ) during matter’s phase change. The results demonstrate that the numerical approach is reliable to simulate air flow over the microtextured surfaces when solving Navier–Stokes equations. The velocity profile experiments exhibit lower drag force (by 6.9–16.9%) on the microtextured surfaces as a result of the wall shear stress and boundary layer thickness diminution. The textured surfaces further aid in enhancing the heat transfer during condensation, due to 8.6–25.7% higher surface temperature differentials ( ΔTs ), heat fluxes ( q ) and condensation heat transfer coefficients ( h ), when compared to the untextured surfaces.