The Effect of Heat Transfer Area Roughness on Heat Transfer Enhancement by Forced Convection

The paper deals with the visualization of temperature fields in the vicinity of profiled heat transfer surfaces and a subsequent analysis of local values of Nusselt numbers by forced air convection in an experimental channel. Holographic interferometry was used for visualizing the temperature fields. Experiments were carried out at Re 462 up to 2338 at the distances between heat transfer surfaces of 0.025m and 0.035 m. Temperature contours were determined from the obtained images of holographic interferograms of temperature fields and the local values of Nusselt numbers along the profiled surface for x/s = 0 up to x/s = 1.25 were calculated from them. A significant effect of the profiled surface on the local values of Nusselt numbers can be observed from the obtained results.