International Journal of Heat and Mass Transfer, Vol.132, 593-605, 2019
Experimental study on distribution parameter characteristics in vertical rod bundles
The drift-flux model is important for rod bundle two-phase flow analysis. A 5 x 5 rod bundles experiment has been performed under air-water two-phase flow conditions. The superficial liquid velocity ranges from 0.00 to 1.50 m/s while the superficial gas velocity ranges from 0.02 to 6.00 m/s. The void fraction has been measured by the impedance meter. Four typical drift-flux models developed for rod bundles have been compared with present data. By analyzing the experimental data and visualization, the distribution parameter may be influenced by the flow recirculation and turbulence significantly. in order to consider these two effects, a critical liquid velocity has been defined to determine which effect is dominant as the increase of liquid velocity, and a new critical void fraction correlation related to the flow regime transition from cap-bubbly to cap-turbulent flow is incorporated to determine the distribution parameter. The new drift-flux model developed from existing models shows a good prediction capability. (C) 2018 Elsevier Ltd. All rights reserved.