The effects of V-nozzle inserts on heat transfer and friction characteristics in a uniform heat flux tube are experimentally
studied. Three different pitch ratios (PR) of V-nozzle arrangements in the test tube are introduced with PR=2.0, 4.0, and 7.0, in
each run. The results of experimental investigations of heat transfer, friction characteristic and enhancement efficiency are
presented. It is found that using the V-nozzle can help to increase considerably the heat transfer rate at about 270% over the plain
tube. A maximum gain of 1.19 on enhancement efficiency is obtained for the smallest pitch ratio used, PR=2.0. 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.