MODELLING REWETTING OF HEATED SURFACES AS INTERMITTENTLY BURSTING LIQUID-METAL CONTACTS
Understanding of the rewetting behavior of heated vertical fuels pins is an important part of establishing reliable cooling of a PWR core following a loss of coolant accident (LOCA). Ahead of the quench front, complex and chaotic processes occur over a very small axial range, where high temperature gradients exist. In particular, repeated cyclic wetting and explosive evaporation at frequencies in the range 0.1 to 1.0 kHz is observed experimentally1. Despite extensive experimental and theoretical studies, the heat transfer mechanism in this region is still not well understood. In this paper we propose a mechanism, based on these observations, to explain the cyclical behavior. This postulated mechanism is transient near-surface cooling, followed by temperature recovery, of the metal substrate, with explosive vaporization when the homogeneous nucleation temperature is restored at the metal-water interface. A one-dimensional model of this cyclical process is constructed. The model indicates that the mechanism is plausible, predicting the observed periodic behavior, with predicted frequencies consistent with those observed in experiments.
Muhammad Ilyas Simon P.Walker Simon P.Walker
Department of Mechanical Engineering,Imperial College London London, SW7 2AZ, UK Department of Chemical Engineering, Imperial College London London, SW7 2AZ, UK
国际会议
18th International Conference on Nuclear Engineering(第18届国际核能工程大会 ICONE 18)
西安
英文
1-7
2010-05-17（万方平台首次上网日期，不代表论文的发表时间）