NUMERICAL STUDY OF ENHANCING HEAT TRANSFER USING TWISTED TAPE INSERTS

Abstract

In the present work, a numerical study of heat transfer for flow inside tube using twisted tapes inserts is presented. Four models have been studied which are plain tube, tube with single twisted tape, tube with double twisted tapes co-swirling flow and tube with double twisted tapes counter swirling flow. The effect of twisted tape pitch and width ratio on heat transfer, Nusselt number, pressure drop and effectiveness are studied. It is found that Nusselt number, effectiveness and pressure drop are increased as pitch ratio decreased. Also, the results show that counter swirling tape inserts has Nusselt number higher than co-swirling tapes, single tapes, and plain tube by about 5-9 %, 14-22 %, and 55-80 % respectively. The results indicate also that twisted tapes with clearance ratio are less effective compared to the types of zero clearance (tight fit tapes). Finally, a good agreement has been found between the present numerical results and published experimental results.