Experimental Study of Heat Transfer for Wavy Twisted Tape Insert of Various Pitches Placed in a Circular Tube

Abstract

The present work shows the results obtained from experimental investigations of the augmentation of turbulent flow heat transfer in a horizontal tube by means of wavy twisted tape inserts with air as the working fluid. Experiments were carried out for plain tube with/without wavy twisted tape insert at constant wall heat flux and different mass flow rates. The wavy twisted tapes are of same wave-width, but three different twist ratios as 8.33, 9.79 & 10.42. The Reynolds number varied from 4000 to 9500. Both heat transfer coefficient and pressure drop are calculated and the results are compared with those of plain tube. It was found that the enhancement of heat transfer with wavy twisted tape inserts as compared to plain tube varied from 17% to 45 % for various inserts. Also the results are compared with the plane twisted tape insert.