An experimental investigation of thermal and frictional characteristics by varying the location of the perforation in the conical insert of a heat exchanger tube.

In the present work, the effect of perforations in the conical inserts of fixed diameter ratio (d/D= 0.3) and pitch ratio (p/D=2) at various locations is studied. The location of perforations (x/L) is varied from 0.25-0.75 in the study. The heat transfer and fluid flow performance of these perforated inserts are compared with the imperforated insert. The variations of Nusselt number and friction factor by varying Reynold's number in the range of 4100-14200 are discussed for different geometries of conical inserts. The temperature and velocity profiles obtained by the numerical simulations are also presented. Highest Nusselt number enhancement is noted in the case of imperforated conical insert, whereas the lowest frictional loss is noted for perforated insert having (x/L=0.25). [ABSTRACT FROM AUTHOR]