Heat Transfer has special importance in engineering applications. So, researchers have suggested different new idea to increase heat transfer and using nanofluid is one of these methods In recent years, new methods have been used. One of these methods is the use of nanofluids, ., because nanofluids have higher heat transfer potential than base conventional fluids. In this investigation effect of suspended CuO nanoparticles with volume fraction of 0.005 into base water fluid is considered under turbulent flow regime inside double tube counter heat exchanger. It was observed that suspending pre-mentioned amount of nanoparticle augmentate heat transfer capability of conventional water fluid. On the other side, it leads to increase pressure drop and friction factor of water base fluid. Finally they conclude that positive effect of heat transfer augmentation is so stronger than negative effect of increasing pressure drop and friction factor that motivate to utilize this nanofluid in practical applications. تفاصيل المقالة