注气对低压自然循环回路中流动闪蒸的影响

Effect of gas injection on flashing flow in low pressure natural circulation loop

为了提高自然循环系统流量、增加系统稳定性,深入了解注气对流动闪蒸现象的影响,以水和空气为介质,研究注气条件下低压自然循环流动闪蒸过程循环流量变化、温度变化及上升段流型演变过程。描述了不同注气方式(直接注气、多孔介质注气)及注气量对流动闪蒸过程的影响。研究发现,上升段内流型及流型演变与注气量大小密切相关。另外,注气可以有效提升系统流量,并且抑制自然循环系统的流动不稳定。给出了不同注气量下上升段内流体温度变化趋势,发现直接注气对自然循环流量的提升效果更明显,相比多孔介质注气方式,在相同注气量下,系统循环流量提高约5%~10%。

In order to increase the flow rate and stability of natural circulation system,and deeply understand the influence of gas injection on the flashing flow phenomenon,water and air were used as the media to investigate the effect of gas injection on the low pressure natural circulation flashing flow process,including the changes of circulation flow rate,temperature and flow pattern in the rising section.In tests,various injection methods including direct gas injection and porous media gas injection,and gas injection rates were applied to assess their potential influence on the flashing flow phenomenon.Results show that,in the rising section,the type of flow patterns and flow pattern evolution processes are closely related to the gas injection rate.In addition,system flow rates are effectively increased and the flow instability in the natural circulation loop is to a large degree inhibited due to the gas injection.As for two types of gas injection methods,the changing tendencies of temperatures in the rising section were compared.The results indicate that the direct gas injection method is more effective in enhancing the natural circulation flow rate,which can increase the system flow rate by 5%~10%with the same gas injection volume,comparing with the porous media gas injection method.