Investigation of heat transfer in corrugated channel with pulsating flow

This study presents hydrodynamics and heat transfer of steady and pulsating flow in a rectangular grooved channel for the Reynolds number range of 2x103≤Re≤6.5x103. Three different grooved channel configurations are created by shifting the bottom wall. The Particle Image Velocimetry (PIV) method is employed for hydrodynamic investigation. Streamlines, velocity vectors, vorticity contours are plotted to reveal massive flow motions and flow patterns. Results showed that groove and mainstream interaction is poor at low Reynolds numbers, but it gets better as the Reynolds number increased. Flow pulsation significantly empowers the penetration of mainstream into the groove section; however, pulsation frequency has an important effect on this phenomenon. Moreover, Reynolds stress and root mean square of the fluctuations are presented to document turbulence statistics. In the heat transfer experiments, the positive effects of the improvement of the groove mainstream interaction and an increase of the turbulence mixing are observed. Heat transfer enhancement, pressure drop trade-off are considered by calculating the thermal performance factor. Pulsating flow caused additional heat transfer enhancement. However, it is a more effective method in low Reynolds numbers. Shifting the bottom wall of the channel does not have an important effect on flow and heat transfer. In addition to the experimental part, a numerical study is carried out to examine the effect of groove aspect ratio and optimum aspect ratio for steady flow.