本文係以數值模擬與實驗的方式探討水平方形封閉容器內氧化鋁-水奈米流體自然對流熱傳遞特性。在方形封閉容器內，其上下水平壁面為加熱/冷卻等溫壁面，其餘邊壁為絕熱壁。本文考慮物理模型之熱傳遞條件為頂部加熱底部冷卻及底部加熱頂部冷卻兩種邊界條件，熱傳實驗之探討主要參數及其範圍分別為：冷熱壁溫差10℃、奈米微粒體積濃度0.1% ~ 4%、及普朗特數為6.06。此外，針對實驗模型進行相對應之數值模擬分析，主要針對奈米微粒之沉澱效應與熱泳效應對容器內奈米流體自然對流熱傳現象的影響進行探討，並與實驗結果相互佐證，藉以釐清奈米流體在自然對流環境下的熱傳行為。

The present study deals with natural convection heat transfer characteristics in a horizontal square enclosure filled with Al2O3-Water nanofluid. The enclosure is heated
differentially across the two horizontal isothermal walls, while the other side-walls are thermally insulated. The heat transfer experiments for natural convection in the enclosure have been undertaken for the relevant parameters in the following range： temperature difference is 10℃, the volume fraction of nanoparticles is 0.1% ~ 4%,and the Prandtl number is 6.15 ~ 6.20.Numerical simulations corresponding to the experimental measurements have been
performed to elucidate influence of thermophoresis and sedimentation of nanoparticles.Comparision between the measured heat transfer results and the numerical prediction has been made to valid at the numerical simulations

Beghein, C., Haghighat, F., and Allard, F., “Numerical Study of Double-Diffusive Natural Convection in a Square Cavity,” Int. J. Heat Mass Transfer, Vol. 35, No. 4, pp.833-846, 1992.
Cerbino R, Vailati A, Giglio M. “Fast-onset Soret-driven convection in a colloidal suspension heated from above. ” Philos Mag, Vol.83, pp.2023-2031, 2003.
Chang, B.H., Mills, A.F., and Hernandez, E., "Natural convection of microparticle suspensions in thin enclosures," Int. J. Heat and Mass Transfer Vol. 51, pp.1332-1341 , 2008.
Charunyakorn, P., Sengupta, S., and Roy, S. K., “Forced Convection Heat Transfer in Microencapsulated Phase Change Material Slurries: Flow in Circular Ducts, ” Int. J. Heat Mass Transfer, Vol. 34, No. 3, pp3 819-833, 1991.
Choi, S. U. S., “Enhancing Thermal Conductivity of Fluids with Nanoparticles,” ASME, FED Vol. 231/MD-Vol. 66, pp. 99-105, 1995.Das, S. K., Putra, N., Thiesen, P., and Roetzel, W., “Temperature Dependence of Thermal Conductivity Enhancement for Nanofluids”, Transactions of ASME, Journal of Heat Transfer, Vol. 125, pp. 567-574, 2003.
Cioni, S. Ciliberto, S. and Sommeria, J., “Experimental study of high-Rayleigh-number convection in mercury and water,” Dynamics of Atmospheres and Oceans,Vol.24, Issues 1-4, pp.117-127, 1996.
Ding, Y., and Wen, D., “Particle Migration in a Flow of Nanoparticle Suspensions,” Powder Technol., Vol. 149, pp.84-92, 2005.
Hwang, K. S., Lee J. H., and Jang, S. P., “Buoyancy-driven Heat Transfer of Water-based Nanofluids in a Rectangular Cavity,” Int. J. Heat Mass Transfer, Vol. 50, pp.4003-4010, 2007.
Ho, C. J., “A Continuum Model for Transport Phenomena in Convective Flow of Solid-Liquid Phase Change Material Suspensions,” Applied Mathematical Modelling, Vol. 29, pp. 805-817, 2005.
Khanafer, K., Vafai, K., and Lightstone, M., “Buoyancy-Driven Heat Transfer Enhancement in a Two-Dimensional Enclosure Utilizing Nanofluids,” Int. J. Heat Mass Transfer, Vol. 46, pp. 3639-3653, 2003.
Lee, S., Choi, S. U. S., Li, S., and Eastman, J. A., “Measuring Thermal Conductivity of Fluids Containing Oxide Nanoparticles”, Transactions of ASME, Journal of Heat Transfer, Vol.121, pp. 280–289, 1999.
Masuda, H., Ebata, A., Teramae, K., and Hishinuma, N., “Alteration of Thermal Conductivity and Viscosity of Liquids by Dispersing Ultra-Fine Particles (Dispersion of Al2O3, SiO2 and TiO2 Ultra-Fine particles)”, Netsu Bussei (Japan) 4, pp. 227–233, 1993
Maïga, S. E. B., Nguyen, C. T., Galanis, N., and Roy, G., “Heat Transfer Behaviours of Nanofluids in a Uniformly Heated Tube,” Superlattices Microstruct., Vol. 35, pp. 543-557, 2004.
Pak, B., and Cho, Y. I., “Hydrodynamic and Heat Transfer Study of Dispersed Fluids with Submicron Metallic Oxide Particles”, Experimental Heat Transfer, Vol. 11, pp. 151-170, 1998.
Putra, N., Roetzel, W., and Das, S. K., “Natural Convection of Nano-Fluids”, Heat and Mass Transfer, Vol. 39, pp. 775-784, 2003.
Roy, G., Nguyen, C. T., Doucet, D., Suiro, S., and Mar, T., “Temperature Dependent Thermal Conductivity Evaluation of Alumina Based Nanofluids”,Proceedings of the 13th for International Heat Transfer Conference, 2006.
Ryskin A, Pleiner H. “Thermal convection in colloidal suspensions with negative separation ratio”. Phys Rev E., E71, 056303, 2005.
Valverde, J. M., and Castellanos, A., “Fluidization of Nanoparticles: a Modified Richardson-Zaki Law,” AIChE Journal, Vol, 52, No. 2, pp.838-842, 2006.
Wang, X. Q., Mujumdar A. S., and Yap, C. “Free Convection Heat Transfer in Horizontal and Vertical Rectangular Cavities Filled with Nanofluids,” Proceedings of the 13th Int. Heat Transfer Conference, 2006.
Wang, X. Q., Xu, X., and Choi, S. U. S., “Thermal Conductivity of Nanoparticle-Fluid Mixture”, Journal of Thermophysics and Heat Transfer, Vol. 13, pp. 474-180, 1999.
Wen, D.S., Ding, Y.L.. “Experimental investigation into the pool boiling heat transfer of aqueous based alumina nanofluids, ” Journal of Nanoparticle Research ,Vol 7, pp.265–274, 2005A.
Wen, D.S., Ding, Y.L. “Formulation of Nanofluids for Convective Heat Transfer Applications,” Int. J. Heat and Fluid Flow, Vol. 26, pp. 855-864, 2005B.
林建中, “矩形容器內奈米流體之自然對流熱傳現象之研究,” 國立成功大學機械工程研究所碩士論文, 2004.
陳苗汶, “方形容器內奈米流體之自然對流熱傳模式與數值模擬研究,” 國立成功大學機械工程研究所碩士文,2007.
張裕昇, “方形容器內奈米流體之自然對流熱傳現象之實驗研究,” 國立成功大學機械工程研究所碩士論文, 2006.
劉文恭, “方形容器內氧化鋁-水奈米流體之自然對流熱傳實驗研究,” 國立成功大學機械工程研究所碩士論文, 2007.