No abstract

This study investigates the influence of twisted tape inserts on a flow pathway in transverse direction of a flow situation. An array of twisted tapes was mounted on the confined channel to disturb the flow to enhance the heat transfer. The test section had 20 twisted tapes of 35-mm height, 10-mm width and a twist angle of 180°mounted on a silica gelcoated plate. Experiments were conducted on the fabricated experimental setup for different discharge conditions. The Reynolds number considered for the study ranged from 2300 to 3500, and the heat inputs varied from 50 to 250 W, with an interval of 50 W. To visualize the presence of twisted tapes on the flow path, the rectangular channel was visualized by laser flow visualization method, which reported the impact of the twisted tapes on the flow. The existence of twisted tape affects the flow, and it forms a swirl that provides a proper mixing of fluid to enhance heat transfer. The outcome of the present investigation provides a solution to enhance heat transfer and proposes the use of twisted tapes instead of using segmented fins in design of fins.

No abstract

Heat transfer augmentation finds its significance in many uses such as air conditioning, heat exchanger and refrigeration structures. On heat transfer augmentation many researchers conducted experimental and numerical to develop various techniques and methods. Heat transfer enhancement techniques are used to nurture the heat transfer rate without disturbing the complete performance of the system. The energy transport is considered enhanced if the flow is agitated and mixed well. This is the fundamental principle in the development of enhancement techniques that generate swirl flows. Nowadays, baffle inserts have widely been applied for improving the convective heat transfer in various applications due to their effectiveness, low cost and easy setting up. In this experiment an array of straight flat baffles was mounted transversely to the direction of air flow in a rectangular cross-sectioned duct and experiment was conducted for different Reynolds numbers. It is proposed to conduct the investigation to evaluate the influence of the presence of straight flat baffles on the flow path. It is observed experimentally that the straight flat baffles influence greater rate of heat transfer than that of the channel without baffles. The flow visualization for various Reynolds numbers also reports the significance of the presence of straight flat baffles in transverse directional flow.