CFD Analysis to Increase Heat Transfer in Pipe with Combined Effect of Circular Perforated Ring and Twisted Tape Insert

Abstract

Enhancement of heat transfer in a pipe can be achieved by the use of passive techniques like circular perforated ring (CRP) insert and twisted tape insert. When these techniques were used by the researchers, they show an increase in thermal performance of heat exchangers. In this paper, combined effect of both the technique CRP insert and twisted tape insert on heat transfer in pipe is investigated. For CFD analysis, a model of pipe of 1.4 m length and 68 mm diameter is created and is tested for Reynolds’s number between 7000 and 22,000. The parameters for CPR inserts are thickness ratio (t/d) = 0.0075, pitch ratio (PR) = 1, diameter ratio (d/D) = 0.8 and for tape insert are twist ratio (TR) of (1, 2, 3 and 4) and width ratio of 0.5. The pipe is provided with the flux of 1000 W/m2 on outer surface. Results of heat transfer (Nu) and friction factor (f) for different twist ratio are then compared.