Effect of thermophoresis particle deposition on mixed convection from vertical surfaces embedded in saturated porous medium

摘要

Purpose - The aim of this paper is to formulate and analyze thermophoresis effects on mixedrnconvection heat and mass transfer from vertical surfaces embedded in a saturated porous media withrnvariable wall temperature and concentration.rnDesign/methodology/approach - The governing partial differential equations (continuity,rnmomentum, energy, and mass transfer) are written for the vertical surface with variable temperaturernand mass concentration. Then they are transformed using a set of non-similarity parameters intorndimensionless form and solved using Keller-box method.rnFindings - Many results are obtained and a representative set is displaced graphically to illustrate therninfluence of the various physical parameters. It is found that the increasing of thermophoresis constant orrntemperature differences enhances heat transfer rates from vertical surfaces and increases wallrnthermophoresis velocities; this is due to favorable temperature gradients or buoyancy forces. It is alsornfound that the effect of thermophoresis phenomena is more pronounced near pure natural convection heatrntransfer limit, because this phenomenon is directly temperature gradient- or buoyancy forces-dependent.rnResearch limitations/implications - The predicted results are restricted only to porous mediarnwith small pores due to the adoption of Darcy law as a force balance.rnOriginality/value - The paper explains the different effect of thermophoresis on forced, natural andrnmixed convection heat, and mass transfer problems. It is one of the first works that formulates andrndescribes this phenomenon in a porous media. The results of this research are important for scientificrnresearches and design engineers.