Abstract
With regard to the design of a natural circulation system, the steady-state behavior of which is an important evaluate indicator, because it can directly reflect the flow capacity and heat transfer capacity. Previous scholars put lots of theoretical and experimental works on the steady-state characteristic of high-pressure natural circulation, while they done little on the open natural circulation, especially on the flashing-driven open natural circulation. In fact, the steady-state characteristic of the flashing-driven open natural circulation is much more complex, due to the existence of flashing in the riser, which leads the uncertainty of two-phase region length and void fraction distribution in the riser. On the other hand, the unambiguous mathematical expression of relation between mass flowrate and heating rate is hard to acquire, by the integral of steady momentum equation, due to the circuit integral quantity of accelerated pressure drop is not equivalent to zero. In this paper, the mathematical expression between the flashing- driven natural circulation mass flow rate and heating rate was put forwards by the circuit integral of steady momentum equation. The results showed good agreements with corresponding experimental data. The analysis results can provide the technical supports for the design of open natural circulation system.
