Analysis of Heat Transfer and Frictional Characteristic in Circular Tube Fitted with V-Nozzle Turbulators

The effects of V-nozzle inserts on heat transfer and friction characteristics in a uniform heat flux tube are experimentally studied. The v-nozzle with pitch ratio 5.0 used. Experimental investigations have been carried out to study the effects of the V-nozzle turbulators on heat transfer augumentation, friction and enhancement efficiency, in a circular tube. It is found that using the V-nozzle can help to increase considerably the heat transfer rate at about 140% over the plain tube. A maximum gain of 1.19 on enhancement efficiency is obtained for the pitch ratio used, PR=5.0. This indicates that the effect of the reverse/re-circulation flows can improve the heat transfer rate in the tube. In addition, correlations from the results are presented.