Showing 3 results for Nanofluid
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Volume 1, Issue 1 (9-2014)
Abstract
Copper oxide nanofluid that is obtained by dispersion of copper oxide nanoparticles in water base fluid is used as heat pipe working fluid. Nanofluids because of having better thermophysical properties in comparison with conventional heat transfer fluids, cause heat pipe performance improvement as an effective heat transfer equipment. In this work, a computational fluid dynamic method (CFD) is used to study the effect of using nanofluid and varying volume fraction, size and shape of suspended nanoparticles in nanofluid on heat pipe thermal performance. The results show thermal resistance reduction and heat pipe performance improvement by using nanofluid in comparison with pure water. Also volume fraction enhancement, nanoparticle’s diameter reduction and using cylindrical nanoparticles cause the evaporator and condenser temperature gradient reduction that in low volume fractions the effect of using nanoparticles with small diameter on heat transfer is more than using non spherical nanoparticles
Mrs. Zahra Hassani, Dr. Abdolrasoul Pouranfard, Prof. Hajir Karimi,
Volume 4, Issue 1 (9-2023)
Abstract
In this study, the effect of adding polyisobutylene (PIB) as drag reducing agent (DRA) and nanoSiO2 particles as heat transfer enhancer to crude oil, separately and also the simultaneous addition of these materials to crude oil as poly-nanofluids (PNFs) in a vertical pipe and under constant heat flux conditions is investigated. The use of drag reducers is one of the most important and simplest methods to overcome some of the energy losses during fluid transpotation. The aim of this study is to investigate the effects of PIB solution and crude oil/silica nanofluid, separately and also the simultaneous effect of adding these two materials, called polyanofluid, on heat transfer and drag reduction in a vertical pipe. In order to make PNFs, polymer-based solutions with concentrations of 10-30 ppm are prepared. Then, nanoSiO2 with concentrations of 0.1-0.5wt% are added to the base fluid. The experiments were performed in the range of Reynolds 5800-8700 and temperature was 25°C. Experimental conclusions predicted that with increasing Reynolds number, temperature and concentration, Nusslet number and heat transfer rate in supplied nanofluids and PNFs enhanced with nanoparticle concentrations, while PIB concentration cause to reduce thermal propertied and improve the tribological properties of prepared PNFs. This occurrence can be attributed to the formation of the polymeric layer around the nanosilica particles.
Morteza Deilami, Pedram Pournaderi,
Volume 4, Issue 1 (9-2023)
Abstract
Heat transfer has an effective role in industrial and engineering applications. In this study, the effect of Al2O3 nanoparticles on laminar forced convection heat transfer flow in a tube is studied. Governing Equations are discretized using the finite difference method on a staggered grid. Nanofluid flow is simulated using single-phase and mixture models. Simulation results show that the average Nusselt Number increases with an increase in the Reynolds Number. Also, by increasing the volume fraction, the average Nusselt number and consequently the heat transfer rate increases. The results of the mixture model are in better agreement with experimental results than the single-phase model.
