Sains Malaysiana 41(12)(2012): 1643–1649

 

Mixed Convection Flow about a Solid Sphere Embedded in a Porous Medium

 Filled with a Nanofluid

(Aliran Olakan Campuran terhadap Sfera Pejal yang Terbenam dalam Medium Berliang

dengan Nanobendalir)

 

Leony Tham

Fakulti Industri dan Asas Tani, Universiti Malaysia Kelantan, 17600 Jeli, Kelantan

Malaysia

 

Roslindar Nazar*

Pusat Pengajian Sains Matematik, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor, Malaysia

 

Received: 18 May 2012 / Accepted: 31 July 2012

 

ABSTRACT

A steady laminar mixed convection boundary layer flow about an isothermal solid sphere embedded in a porous medium filled with a nanofluid has been studied for both cases of assisting and opposing flows. The transformed boundary layer equations were solved numerically using an implicit finite-difference scheme. Three different types of nanoparticles, namely Cu, Al2O3 and TiO2 in water-based fluid were considered. Numerical solutions were obtained for the skin friction coefficient, the velocity and temperature profiles. The features of the flow and heat transfer characteristics for various values of the nanoparticle volume fraction and the mixed convection parameters were analyzed and discussed.

 

Keywords: Boundary layer; mixed convection; nanofluid; porous medium; solid sphere

 

ABSTRAK

Aliran lapisan sempadan olakan campuran berlamina mantap terhadap sfera pejal isoterma yang terbenam dalam medium berliang dengan nanobendalir telah dikaji bagi kes aliran membantu dan aliran menentang. Persamaan lapisan sempadan terjelma diselesaikan secara berangka dengan skema beza terhingga tersirat. Tiga jenis nanozarah dalam bendalir asas air dipertimbangkan, iaitu Cu, Al2O3 and TiO2. Penyelesaian berangka diperoleh bagi pekali geseran kulit, profil halaju dan profil suhu. Ciri-ciri aliran dan pemindahan haba bagi pelbagai nilai parameter pecahan isi padu nanozarah dan parameter olakan campuran dianalisis dan dibincangkan.

 

Kata kunci: Lapisan sempadan; medium berliang; nanobendalir; olakan campuran; sfera pejal

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*Corresponding author; email: rmn@ukm.my