The Measurements of Natural Convection Heat Transfer in Enclosures Using Analogy Experimental Methodology

Hydrogen is arousing interests as the viable, clean, future energy source. However it will be clean as long as its production method does not impose environmental burdens. One of the promising production methods of hydrogen is to use the heat from an HTGR (High Temperature Gas-cooled Reactor). However the gas coolant, of which less experience has been accumulated, requires a more detailed knowledge of heat transfer phenomena: Due to its relatively low heat capacity, the radiation heat transfer fraction increases. The property changes sensitive to the temperature causes the significant buoyancy effect. High and expensive facilities are needed to simulate the high-buoyancy phenomena. Heat leakage from test facility to structural materials is also unavoidable. However, in order to overcome those problems, an experimental methodology using analogy concept has been developed. This study, as the extended study for the further development of the methodology, simulates the natural convection in enclosures for the various Rayleigh numbers and aspect ratios(H/L) and measures the heat transfer rates