HEAT TRANSFER AUGMENTATION IN A CIRCULAR TUBE USING TWISTED TAPE INSERT: A REVIEW

Heat transfer augmentation techniques refer to different methods used to increase rate of heat transfer. These techniques broadly are of three types viz. passive, active and compound techniques. The present paper is a review of one of the passive augmentation techniques used in a circular tube which is twisted tape. In the present paper emphasis is given to works dealing with twisted tape inserts because according to the recent studies, these are known to be economic tool in the field of heat transfer enhancement. Passive techniques, where inserts are used in the flow passage to increase the heat transfer rate, are advantageous compared with active techniques, because the insert manufacturing process is simple and cheap and these techniques can be easily employed in an existing heat exchanger. The thermohydraulic performance of above inserts depends on the various factors such as flow conditions, geometry of pipe and insert configurations.