Experimental and CFD studies on heat transfer and friction factor characteristics of a tube equipped with modified twisted tape inserts

This paper reports experimental and Computational Fluid Dynamics (CFD) investigations on the friction factor, Nusselt number and thermal-hydraulic performance of a tube equipped with the classic and three modified twisted tape inserts. The results showed that the Nusselt number and performance of the jagged insert were higher than other ones. Maximum increase of 31% and 22% were observed in the calculated Nusselt and performance of the jagged insert as compared with those obtained for the classic one. The higher turbulence intensity of the fluid close to the tube wall has been expressed as the main reason for the experimental observations. (c) 2008 Elsevier B.V. All rights reserved.