UBC Theses and Dissertations
Forced convection heat transfer to turbulent flow of supercritical water in a round horizontal tube Bazargan, Majid
Very little heat transfer data for supercritical fluids can be found in the literature over the last twenty-five years. Most of the available data are for vertical and not horizontal flows. This investigation focuses on horizontal flows. The pilot SCWO system, constructed at the Department of Mechanical Engineering, UBC in partnership with NORAM, a Vancouver based engineering company, was used to accomplish this. The current data was obtained with accurate state of the art measurement and data acquisition equipment. Measurements of heat transfer to pure supercritical water are carried out in the test section before oxygen and sample wastes are introduced to the system. This database was used to critically review and evaluate available empirical, forced convection, heat transfer correlations. For this study, a new approach leading to a more accurate empirical correlation for the flows with negligible effects of the flow acceleration and the buoyancy was offered. The conditions for the onset of buoyancy and acceleration forces were also investigated. For flows unaffected by buoyancy and acceleration, a numerical model, incorporating recent improvements in turbulence modeling, was developed. The model was found to predict the data of the current study very well. It also predicted the available data from other studies well. Overall, it can be said that this study encapsulates all the necessary knowledge required by an engineer to design a horizontal SCW system that operates within a range of safe operating conditions (i.e. no deteriorated heat transfer due to buoyancy and/or acceleration effects).
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