Intensification of heat transfer behind the backward-facing step using tabs

The influence of tab size and location on the flow structure, distribution of pressures on the surface, and heat transfer in the separation region behind the backward-facing step at Reynolds number Re = 4000 was experimentally investigated. The effect of tabs on the distribution of the local pressure and heat transfer coefficients in the longitudinal and transversal directions was studied. The presence of tabs significantly intensifies the heat transfer directly behind the separation point and brings the region of maximum heat transfer closer to the step. There is a strong uneven distribution of pressure coefficients and Nusselt numbers in the transverse direction due to the formation of vortical wake. The results of measurements are compared with the case of using two-dimensional obstacles in the form of solid ribs; the features of the development of the flow and heat transfer behind 3D tabs are analyzed. It is shown that the main difference in the installation of two-dimensional and three-dimensional obstacles is observed mainly in the immediate vicinity of the flow separation point at X/H < 6