HEAT EXCHANGE IN TURBULENT FLOW. PART 1. TURBULENT PRANDTL NUMBER

Knowledge of the characteristics of heat-exchange intensity in a turbulent coolant flow is one of the main problems of safety validation of nuclear power facilities. The maximum temperature of fuel elements and other structures is determined on the basis of the heat exchange coefficients. However, most computational relations of empirical or semi-empirical character have in many cases an error +/-(15-20)%, which is unsatisfactory given the current requirements of the design of nuclear power facilities. The present review of the investigations of the turbulent boundary layer for different media performed in our country and abroad in 1950-2016 makes it possible to identify a different approach to the analysis of heat exchange intensity. The first part of the review examines the structural characteristics of the boundary layer and the evaluation of the turbulent Prandtl number Pr-T for different media.