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

In this study, the behavior of nanoparticles using a numerical model is discussed. For this study a model for the expansion in free convection heat transfer and mix in a rectangular container with dimensions of 1 × 4 cm using Nano-aerosols in the air is going when copper nanoparticles, use and by changing the temperature difference between hot and cold wall, we will examine its impact on the rate of heat transfer. The simulation involves two-dimensional flow simulation and relaxed state of constant flux in free convection on the two lateral sides and on the top face of constant temperature (cold plate) at 300 K was considered And at low temperature (heat plate) in three modes 350, 400 and 450 K were compared. Temperature distribution, velocity, surface heat flux and Nusselt number during the course of our review.Finally, enhanced heat transfer in the presence of copper nanoparticles and changes in the temperature difference between warm and cold wall was observed تفاصيل المقالة

In the present study, removal of chromium, lead and nickel by using polypyrrol and its composites from the aqueous environment were simulated. In order to prepare polypyrrol and its composites, iron chloride oxidant with 8 g, water solvents, acetonitrile and ethyl acetate were used in the presence of two additives, polyvinyl alcohol and polyethylene glycol at concentrations of 1.5 and 2. Batch quarantine method was used to measure the removal of these metals from the aqueous environment. The simulated results showed that all polypyrrols and their composites are suitable for the removal of +6 chromium. The highest adsorption of total chromium and +6 chromium was observed by polypyrrol and polyethylene glycol composites with 90.7% and 96.2%, respectively. However, polypyrrol and its composites are undesirable for removal of lead, cadmium and nickel. The highest removal rates of lead and cadmium by activated carbon powder were 99.5% and 78.08%, respectively. Also, the percentage of nickel removal by some polypyrrols was lower than activated carbon with 14.96% removal. Some polypyrrols also have a higher percentage of knockout than activated carbon, which does not seem very high in comparison with other heavy metals. In general, it can be found that the use of polypyrrol composites, especially polypyrrol and polyethylene glycol composites, are suitable for the removal of total chromium and +6 chromium from the aqueous environment, but are undesirable for the removal of lead and nickel. تفاصيل المقالة