倒U型管蒸汽发生器自然循环回流特性研究

自然循环在核动力工业中有重要的应用。以AP1000自然循环压水反应堆一回路系统的蒸汽发生器为对象，建立自然循环系统蒸汽发生器倒U型管内单相水回流的数学模型，并进行了计算，得出了蒸汽发生器倒U型管内正流和回流流量、正流管管长和回流管管长分布等。研究结果表明，回流能大幅降低自然循环的重位压头、流量和放热量，不利于自然循环。

Study on Reverse Flow Characteristics Under Natural Circulation in Inverted U-Tube Steam Generator

Natural circulation is important for application in the nuclear power industry. Aiming at the steam generator of AP1000 pressurized water reactor loop, the mathema-tical model was established to analysis the reverse flow of single-phase water in the inverted U-tubes of a steam generator in a natural circulation system. The length distribution and the mass flow rates in both tubes with normal and reverse flow were determined respectively. The research results show that the reverse flow may result in sharp decrease of gravity pressure head, circulation mass flow rate and heat release rate of natural circulation. It has adverse influence on natural circulation.