Performance Study on a Newly-structured Oil Cooler for Nuclear Steam Turbines

To overcome the deficiency of traditional segmentally-baffled shell-and-tube oil coolers, a two-layer continuous helically-baffled shell-and-tube oil cooler was proposed. The shell side streamline distribution as well as the heat-transfer and resistance characteristics were numerically investigated for shell-and-tube oil coolers respectively with segmental baffle, monolayer continuous helical baffle and two-layer continuous helical baffle using Realizable k-ε turbulence model combined with standard wall function. Results show that compared with segmental baffle, the shell-side heat-transfer coefficient of continuous helical baffle is larger, the pressure drop is lower and the comprehensive performance is obviously better, where no flow stagnation zone is found on the shell side. Moreover, the shell-side heat-transfer coefficient of two-layer continuous helical baffle is between that of the segmental baffle and monolayer continuous helical baffle, and its pressure drop is the lowest. Both the two-layer and monolayer continuous helical baffles have almost the same comprehensive performance.