Fluid flow mechanisms for enhancing physical-power processes on structured energy-efficient surfaces with vortex generators

Abstract

Using the RANS approach, the phenomenon of interference of the jet flow during its deceleration with the windward edge of an inclined groove on the streamlined surface and the tornado-like vortex generated at the groove inlet is established. Experiments confirmed emerging of extra-ordinary static pressure drop between the stagnation and rarefaction zones. The backflow velocity increases twice and this velocity magnitude exceeds the mass-average velocity. The study justifies the abnormal separated flow related to heat transfer enhancement for the cases of inclined grooves on a structured plate and the wall of the narrow channel. This phenomenon produces a multiple (up to 6–9 times) growth of the relative friction and heat fluxes inside the grooves (compared to the case of a plain wall). We observe also the acceleration in the near-wall stream caused by a set of single-row inclined groves arranged in a narrow channel. Here the maximum velocity in the stream core within this structured channel increases by more than 1.5 times as compared to peek velocity for a flow in a plane-parallel channel. The study is useful in the aerodynamic design of new energy-efficient groove-structures surfaces.