核电厂汽轮机滑油冷却器新结构性能研究

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

为了克服传统弓形折流板管壳式滑油冷却器的固有缺点,提出了双层连续螺旋折流板管壳式滑油冷却器.采用Realizable k-ε湍流模型结合标准壁面函数的方法,对比分析了弓形折流板管壳式以及单、双层连续螺旋折流板管壳式滑油冷却器的壳侧流线分布及传热和阻力性能.结果表明:与弓形折流板相比,连续螺旋折流板壳侧不存在流动死区,壳侧传热系数有所增大,压降有所降低,综合性能显著提高;双层连续螺旋折流板的壳侧传热系数介于弓形折流板和单层连续螺旋折流板之间,压降最低,综合性能与单层连续螺旋折流板相当.

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 be 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.