Augmentation of natural convective heat transfer in square cavity by utilizing nanofluids in the presence of magnetic field and uniform heat generation/absorption

• Published in: International journal of thermal sciences Vol. 58; pp. 130 - 142
• Main Authors: Teamah, Mohamed A., El-Maghlany, Wael M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Masson SAS 01-08-2012; Elsevier
• Subjects: Absorption coefficient; Applied sciences; Chemistry; Colloidal state and disperse state; Condensed matter: structure, mechanical and thermal properties; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); General and physical chemistry; Hartmann number; Heat generation or absorption; Heat transfer; Magnetic field; Magnetic fields; Magnetohydrodynamics and electrohydrodynamics; Mathematical models; Nanofluids; Nanomaterials; Nanoparticles; Nanostructure; Natural convection; Numerical simulation; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Physics; Square cavity; Theoretical studies. Data and constants. Metering; Thermal properties of condensed matter; Thermal properties of small particles, nanocrystals, nanotubes; Volume fraction; Nanofluids; Numerical simulation; Natural convection; Heat generation or absorption; Square cavity; Magnetic field; Heat transfer; Hartmann number; Nusselt number; Nanoparticle; Nanofluid; Finite volume method; Hartmann flow; Cavity flow; Modeling; MHD flow; Square section
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/j.ijthermalsci.2012.02.029

Natural convection in a square cavity filled with different nanofluids is studied numerically. Both upper and lower surfaces are being insulated, whilst a uniform magnetic field is applied in a horizontal direction. Constant different temperatures are imposed along the vertical walls of the enclosure, steady state laminar regime is considered. The transport equations for continuity, momentum, energy are solved. The numerical results are reported for the effect of Rayleigh number, solid volume fraction and both Hartmann number and heat generation or absorption coefficient on the iso-contours of streamline and temperature. In addition, the predicted results for average Nusselt are presented for various parametric conditions. This study was done for 103 ≤ Ra ≤ 107, 0 ≤ Ha ≤ 60, 0 ≤ ϕ ≤ 0.06 and −10 ≤ q ≤ 10 while the Prandtl number represent water is kept constant at 6.2. The results show that for weak magnetic field; the addition of nanoparticles is necessary to enhance the heat transfer but for strong magnetic field there is no need for nanoparticles because the heat transfer will decrease. On the other hand to augment the heat transfer; nanoparticles volume fraction must be increased but with a small value of heat absorption coefficient (q < 0) at constant Hartmann and Rayleigh numbers.
► Natural convection in cavity filled by different nanofluids is studied numerically. ► The cavity contains heat source and subjected to magnetic field. ► Study ranges 103 ≤ Ra ≤ 107, 0 ≤ Ha ≤ 60, 0 ≤ ϕ ≤ 0.06, −10 ≤ q ≤ 10 and Pr = 6.2. ► For weak magnetic field; addition nanoparticles is necessary to enhance heat transfer. ► To augment the heat transfer; solid volume fraction must be increased.