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The nanofluids are widely used for heat transfer applications in the various engineering applications. The nanoparticles dispersed uniformly in the base fluid on proper mixing. In the present study, Al2O3 and CuO nanoparticles were selected and the changes in the heat transfer coefficient were investigated in the complete laminar and discrete points of transition fluid flow through a copper tube with constant heat flux. The heat transfer coefficient was investigated at different loading of Al2O3 and CuO nanopowders ranging from 0.1 % to 0.5 % of volume concentration in each case for the laminar and transition fluid flow zones, which is then compared with the distilled water as a plain base fluid. It is found that the optimum enhancement in heat transfer is observed at relatively lower volume fraction of nanoparticles ranging between 0.2 to 0.3%. Key words: heat transfer coefficient, nanofluids, heat transfe