Augmentation of Heat Transfer Using Twisted Tube Heat Exchanger

Abstract

Various techniques for improving the heat transfer are referred to as heat enhancement techniques. Heat exchanger with these techniques is called   augmented heat exchanger. The objective is to reduce capital cost, power cost, maintenance cost and space. Twisted tube is a passive technique to enhance the heat transfer. Present twisted tubes are used for long and straight passage tubes. We experimentally investigated the fully developed laminar convective heat transfer and friction factor characteristics in a plain tube and fitted with twist tubes. Experiments were conducted within range of 1200Re   2800.Experiments are performed for Reynolds number ranging from laminar to turbulent. Heat transfer without twisted tube is compared with heat transfer with twisted tube. The experimental results reveal that use of twisted tube leads to increase in heat transfer. Nusselt Number increase with increase in Reynolds Number. Twisted tube is inserted into the flow to provide redevelopment of the boundary layer, to increase the heat transfer surface area and to cause enhancement of heat transfer by increasing the turbulence or rapid mixing. Therefore, a more compact and economic heat exchanger with low lower operation costs can be obtained.