Experimental heat transfer of supercritical carbon dioxide flowing inside channels (survey)

A new reactor concept under development at AECL has the main design objective of achieving a 50% reduction in unit energy cost relative to existing reactor designs. The approach builds on using existing operating supercritical water (SCW) experience and turbines in coal-fired power plants. This SCW CANDU(R)(2) research includes investigating heat transfer and pressure drop at supercritical conditions using carbon dioxide as a modelling fluid as a cheaper and faster alternative to using SCW. Therefore, the objectives are to assess the work that was done with the supercritical carbon dioxide and to understand the specifics of heat transfer at these conditions. Our exhaustive literature search, which included over 450 papers, showed that the majority of experimental data were obtained in vertical tubes, some data in horizontal tubes and just few in other flow geometries. Three modes of heat transfer at supercritical pressures have been recorded: (1) so-called normal heat transfer, (2) improved heat transfer, characterized by higher-than-expected heat transfer coefficient (HTC) values than in the normal heat transfer regime and (3) deteriorated heat transfer, characterized by lower-than-expected HTC values than in the normal heat transfer regime. (C) 2004 Elsevier B.V. All rights reserved.