Heat transfer and friction factor characteristic of spherical and inclined teardrop dimple channel subjected to forced convection

摘要

An experimental and numerical investigation is performed in order to determine the outcome of dimple geometries on the heat transfer and friction factor in a dimple cooling channel subjected to turbulent flow. Two geometries taken into consideration are spherical and inclined teardrop. In order to have a better comparison between the two different dimple channel, the dimple depth, total wetted area of dimple, and dimple pitch have been kept constant. In case of spherical and inclined teardrop dimple channels, heat transfer augmentation, friction losses, and flow pattern have been obtained for a Reynolds Number range from 14,000 to 65,000. The investigation shows that the dimple geometry has a significant contribution to increasing the heat transfer augmentation and determining the flow pattern. The inclined teardrop dimple arrangement shows the maximum heat transfer that is 17% higher than the spherical dimple channel, whereas inclined teardrop dimple results in the rise of friction factor of about 5.93-16.14% times as compared to the spherical dimple within the specified Reynolds number. The inclined teardrop and spherical dimple channel show the heat transfer enhancement of 2.74 to 3.20 times and 2.38 to 2.68 times than that of smooth channels provided thermal boundary conditions and flow conditions are kept same. The numerical study has been performed, which provided a detailed insight into the flow structures and vortex formations in spherical and inclined teardrop dimple channel.