Enhancement of Heat Transfer with Inclined Baffles and Ribs Combined

Abstract

Heat transfer enhancement techniques are found in many of today's processes. Devices such as inclined baffles, rib turbulators, jet impingement, etc., are all used in order to augment the thermal transfer of a process. Inclined baffles have been studied, along with the combination of jet impingement techniques. Inclined baffles enhance heat transfer by enhancing large-scale fluid bulk motion and through tripped boundary layer flow separation. Impinging jets, created by perforating the baffle, create additional heat transfer through flow impingement on the heated surface. Rib turbulators create heat transfer augmentation by disturbing the thermal boundary layer, unlike baffles; ribs enhance heat transfer in areas near the heat transfer surface, leaving the core flow largely undisturbed. This paper describes experimental investigation of heat transfer with turbulent flow in a rectangular channel with inclined solid and perforated baffles combined with rib turbulators. Combining ribs with perforated and inclined baffles yielded an increase in average Nusselt number, albeit with a pressure drop penalty. In situations where rate of heat transfer is critical to the performance of a device, combining ribs with baffle is a viable solution.