As primary separators in pressurized water reactors (PWRs), cyclone separators separate most of the water from vapor-water two-phase mixture, which is important to the safety and economics of nuclear power plants. To improve the performance of cyclone separators, we tested new structures in this study, e.g. porosity and inclined angle of the separator wall. Under different structures, separation efficiency and pressure drop were studied theoretically and experimentally. Results show that each of the structural parameters has an effect on separator performance, but none of the trends is monotonically in experimental ranges. Besides separator structures, the comprehensive performance is also determined by flow patterns. From segregated to homogeneous flow, the separation ability decreases. The separation efficiency is about 5% higher at 20° inclined angle when the superficial velocities are 0.012 and 16 m·s-1 for the liquid and gas, respectively. The separation efficiency is only 91% without an impeller, while it is up to 100% at the same superficial velocities of air and water, 16 and 0.015 m·s-1 , respectively. Based on the study, it is promising to understand deeply the separation mechanism and further to provide data for designing large-scaled separators for advanced pressurized water reactors.
In this paper,we propose a novel probe to identify phases in any two-phase flows where one phase is conductive and the other nonconductive.We can further obtain many parameters such as void fraction,bubble velocity,and interfacial area concentration.Compared with the traditional probe,the novel probe has unique advantages that it is less dependent on water conductance or distance between the electrodes,and that the amplitude is bigger between high and low levels.Theoretical analyses showed that the measurement error became higher when water conductance decreases or distance increases,which is consistent with the theoretical analyses.Experimental results showed that the output signal kept constant with salt content of 0-5% and electrode distance of 0-30 mm in tap water.The level difference was up to 6.4 V,resulting in identifying two phases easily.Time traces of phase identification were completely consistent with the flow structures.
