针对流体体积模型(volume of fluid,VOF)在模拟相间传质过程时需要将界面质量流密度转换为单位体积传质速率的问题,对VOF模型中的界面传质与体积传质转换方法进行了改进。提出一种既解决了网格无关性问题又可以反映局部界面传质特性的...针对流体体积模型(volume of fluid,VOF)在模拟相间传质过程时需要将界面质量流密度转换为单位体积传质速率的问题,对VOF模型中的界面传质与体积传质转换方法进行了改进。提出一种既解决了网格无关性问题又可以反映局部界面传质特性的转换方法,并给出了理论推导证明。推导出相应的网格无关性条件,通过划分3组不同尺寸的网格模拟了汽泡冷凝问题,并在汽泡生长方面对该转换方法加以简单应用,模拟结果与理论分析及实验结果符合良好,合理可行,可广泛应用到多相流中界面传热传质模拟的过程。展开更多
A new capacitance probe is developed for measuring local moisture content in wet porous media. The measurement principle, sensor structure of the probe, dynamic response characteristics and calibration procedure are d...A new capacitance probe is developed for measuring local moisture content in wet porous media. The measurement principle, sensor structure of the probe, dynamic response characteristics and calibration procedure are discussed in detail. The experimental results show that the probe can be used to measure the local moisture content in wet porous media.展开更多
The droplet interacts intensively with surrounding gas when moving and evaporating in the gas,of which the mutual effects of the gas and the evaporating droplet need to be taken into account.For the typical droplet mo...The droplet interacts intensively with surrounding gas when moving and evaporating in the gas,of which the mutual effects of the gas and the evaporating droplet need to be taken into account.For the typical droplet model,the gas parameters are usually considered as that at infinity and the local parameter variation surrounding the droplet is neglected,consequently leading to some discrepancies.This research tries to develop a new moving droplet phase change model with two-phase coupling which characterizes the local parameter variation of gas phase surrounding the evaporating droplet.Firstly,the interaction mechanism of two phases is presented based on the droplet evaporation phenomena.Then,the droplet motion and phase change model is developed through the theoretical derivation.Subsequently,the analysis of the evaporation characteristics of the injected droplets in the hot air is conducted to simulate the operation process of the containment spray system in the nuclear power station.The numerical simulation indicates the refined droplet model is more capable for precise prediction of the situations with large quantities of evaporating droplets and with intensive interactions between two phases.展开更多
文摘针对流体体积模型(volume of fluid,VOF)在模拟相间传质过程时需要将界面质量流密度转换为单位体积传质速率的问题,对VOF模型中的界面传质与体积传质转换方法进行了改进。提出一种既解决了网格无关性问题又可以反映局部界面传质特性的转换方法,并给出了理论推导证明。推导出相应的网格无关性条件,通过划分3组不同尺寸的网格模拟了汽泡冷凝问题,并在汽泡生长方面对该转换方法加以简单应用,模拟结果与理论分析及实验结果符合良好,合理可行,可广泛应用到多相流中界面传热传质模拟的过程。
文摘A new capacitance probe is developed for measuring local moisture content in wet porous media. The measurement principle, sensor structure of the probe, dynamic response characteristics and calibration procedure are discussed in detail. The experimental results show that the probe can be used to measure the local moisture content in wet porous media.
文摘The droplet interacts intensively with surrounding gas when moving and evaporating in the gas,of which the mutual effects of the gas and the evaporating droplet need to be taken into account.For the typical droplet model,the gas parameters are usually considered as that at infinity and the local parameter variation surrounding the droplet is neglected,consequently leading to some discrepancies.This research tries to develop a new moving droplet phase change model with two-phase coupling which characterizes the local parameter variation of gas phase surrounding the evaporating droplet.Firstly,the interaction mechanism of two phases is presented based on the droplet evaporation phenomena.Then,the droplet motion and phase change model is developed through the theoretical derivation.Subsequently,the analysis of the evaporation characteristics of the injected droplets in the hot air is conducted to simulate the operation process of the containment spray system in the nuclear power station.The numerical simulation indicates the refined droplet model is more capable for precise prediction of the situations with large quantities of evaporating droplets and with intensive interactions between two phases.
