Due to the various speculated uses of nanofluids, it has become important to know more about their properties hence the objective of the present study is to investigate the forced convection of nanofluids. The investigation was conducted by using double pipe heat exchanger in counter flow arrangement and the flow was turbulent. Water based nanofluids containing Al2O3 nanoparticles of various concentrations will be tested. Nanofluids are dispersions of nanometer sized metal/metal oxide, carbon nanotubes, diamond or any other nanoparticles in a liquid medium. These fluids have shown a significant increase in the thermal conductivity compared to the base fluid. These fluids have a great potential to replace current coolants and heat transfer fluids in a variety of applications. Heat-Transfer Challenges: The heat rejection requirements are continually increasing due to trends toward smaller features (to <100 nm) for microelectronic devices, more power output for engines. Cooling becomes one of the top technical challenges facing high-tech industries such as microelectronics, transportation, manufacturing, and metrology. Conventional method to increase heat flux rates: extended surfaces such as fins and micro-channels. increasing flow rates increases pumping power.