Abstract
Natural circulation is widely used in the many industries owing to inherent safety. A typical case is Passive Containment Cooling System in the Chinese third-generation nuclear plant HPR1000. It uses an open natural circulation structure and contains an inner-containment heat exchanger, an outer-containment altitude water tank and connecting pipes. The altitude water tank connects with atmosphere, making its operation pressure is atmospheric pressure. For designing such an open natural circulation system, the steady-state flow behavior of of which is an important evaluate indicator, because it can directly reflect the flow capacity and heat transfer capacity of the PCS system. Considering that the long-term stable operating condition of the PCS system is the boiling-driven open natural circulation flow. Therefore, it is of significance to study the steady-state flow characteristics of the boiling-driven open natural circulation system.
In this paper, a theoretical formula to determine the steady-state flow behavior of a open boiling-driven natural circulation. Due to the lack of condensation process of two-phase circulation fluid, the integral result of steady momentum equation is not equal to zero. A special formula processing of accelerated pressure drop integral result is taken in this paper during the formula derivation process. The theoretical analysis results of which were validated by the experimental data. This paper aims at providing technical support for the design of open natural circulation systems.
