جستجوی مقالات مرتبط با کلیدواژه « نفوذ براونی » در نشریات گروه « برق »

In this paper, the nanofluid forced convection heat transfer in the case of single and two phase approachs is studied.The fully-developed flow and steady Darcy-Brinkman-Forchheimer equation is employed in porous channel and is solved with homotopy perturbation method. The thermal equilibrium model is assumed between nanofluid and solid phases. It is assumed that the nanoparticles are distributed non-uniformly inside the channel.As a result, the volume fraction distribution equation is also coupled with governing equations. It is observed that as the Schmidt number is increased, the wall temperature gradient is decreased and as a consequence the local Nusselt number is decreased. The effects of Lewis number, Schmidt number and modified diffusivity ratio on the volume fraction distribution are also studied and discussed. Heat transfer of single and two phase approaches are also compared.

In this paper، the flow field، heat transfer and nanoparticles transport in Al2O3-water nanofluid mixed convection in a square enclosure with inlet and outlet port has been studied numerically. The dimensionless transport equations are solved numerically with a finite volume approach using the SIMPLER algorithm. Nanoparticles transport mechanisms such as Brownian diffusion، thermophoresis and Dufour effect that cause non-uniform concentration distribution are intended in nanoparticles transport model. The study has been carried out for the nanoparticles volume fraction in the range 0 ≤ φb ≤ 0. 04، Richardson numbers 0. 01 ≤ Rif،0 ≤ 1with two Grashof number Grf،0=104، 105. The results show that in mixed convection by increasing volume fraction of nanoparticles and the Grashof number for each Richardson number، the average Nusselt number increases and the transport model by affecting on nanoparticles concentration influence the amount of flow velocity and heat transfer so that in low temperature difference homogenous model and at high temperature difference the transport model predicts higher average Nusselt number.