Intensification of Heat Transfer during Steam Condensation in Process Condenser of NPP Unit Cooling System

Abstract

The paper investigates heat transfer during condensation of water vapor on vertical pipes of the process condenser of the cooling system of a nuclear power unit. The numerical study was performed at different mass flow rates of steam in the range of its change from 20 kg/s to 40 kg/s. Intensification of heat exchange is provided by the use of highly efficient heat exchange profiled tubes. The study used a set of heat exchange tubes (25 mm in diameter and 1.4 mm wall thickness) with the following values of the distance between the grooves of the profiled tube: 0.007075 m, 0.00875 m, 0.00925 m, 0.0105 m. The effect of the groove depth (from 0.0007 to 0.0009 m) on heat transfer during water vapor condensation on vertical pipes was also studied. The study was carried out for the range of changes in the Reynolds number for the condensate film from 5254.2 to 10508.5. The study obtained data indicating an increase in the heat transfer coefficient on the pipe with an intensifier compared to the heat transfer coefficient on a smooth pipe. This analysis did not take into account the change in tube wall temperature.