Natural convection heat transfer of water in a horizontal circular gap

作     者：SU Guanghui Kenichiro Sugiyama WU Yingwei 

作者机构：State Key Laboratory of Multiphase Flow in Power EmgineeringXi'an jiaotong University Xi'an 710049China Faculty of Engineering Hoddaido University North Ward Sapporo 060-8628Japan 

出 版 物：《中国高等学校学术文摘·能源与动力工程》 (FRONTIERS OF ENERGY AND POWER ENGINEERING IN CHINA)

年 卷 期：2007年第1卷第2期

页      面：167-173页

核心收录：

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

基　　金：This work was financially supported by the Japan Society for the Promotion of Science 

主　　题：natural convection downward facing heated surface gap size buoyancy force 

摘      要：An experimental study on the natural convection heat transfer on a horizontal downward facing heated surface in a water gap was carried out under atmospheric pressure conditions. A total of 700 experimental data points were correlated using Rayleigh versus Nusselt number in various forms, based on different independent variables. The effects of different characteristic lengths and film temperatures were discussed. The results show that the buoyancy force acts as a resistance force for natural convecti on beat transfer ona downward facing horizontal heated surface in a confined space. For the estimation of the natural convection heat transfer under the present conditions, empirical correlations in which Nusselt number is expressed as a function of the Rayleigh number, or both Rayleigh and Prandtl numbers, may be used. When it is accurately predicted, the Nusselt number is expressed as a function of the Rayleigh and Prandtl numbers, as well as the gap width-to-heated surface diameter ratio; and uses the temperature difference between the heated surface and the ambient fluid in the definition of Rayleigh number. The characteristic length is the gap size and the film temperature is the average fluid temperature.