DEVELOPMENT AND PRELIMINARILY VERIFICATION OF MULTIPHASE SUBCHANNEL CODE IN COSINE SOFTWARE PACKAGE

抄録

The multiphase subchannel analysis code is an important part of the COSINE software package and was developed on the basis of cosSUBC code, which is a sub-channel code with homogeneous field. The multiphase subchannel analysis code adopted multiphase conservation equations, including the equation of vapor phase, continuous liquid phase, droplet phase and non-condensable gas phase. The staggered discrete scheme in mesh and semi-implicit discrete scheme in time were used to improve the calculation accuracy in this code. Besides, the newton down-hill method was adopted to improve convergence and raise the calculation speed. In this paper, the mathematical methods and physical model of the code were introduced, and some typical examples and experiments were modeled and calculated to verify the correctness of this code. In addition to this, examples of non-condensable gas and some comparison cases about convergence were calculated to verify the computation capacity of the code. The results show that the calculation results were in good agreement with the reference code and the experimental results. The phenomenon of non-condensable gas calculated by the code was reasonable. Besides, the newton down-hill method had a significant effect on improving the calculation speed. The application of the code implies that the code can be used to model and calculate the thermal hydraulics problem in the core of pressurized water reactor.