Numerical Study of Void Fraction Distribution Propagation in Gas-Liquid Two-Phase Flow

A dynamic propagation model was developed for waves in two-phase flows by assuming that continuity waves and dynamic waves interact nonlinearly for certain flow conditions. The drift-flux model is solved with the one-dimensional continuity equation for gas-liquid two-phase flows as an initial-boundary value problem solved using the characteristic-curve method. The numerical results give the void fraction distribution propagation in a gas-liquid two-phase flow which shows how the flow pattern transition occurs. The numerical simulations of different flow patterns show that the void fraction distribution propagation is determined by the characteristics of the drift-flux between the liquid and gas flows and the void fraction range. Flow pattern transitions begin around a void fraction of 0.27 and end around 0.58. Flow pattern transitions do not occur for very high void concentrations.     

中国反应堆冷中子源现状与展望

本文指出我国处于国防科学发展的关键时期,介绍了冷中子源系统在反应堆工程和物质科学研究中的特殊作用,分析了俄罗斯等国冷中子源系统的特点,提出了关于方案选择的一些考虑,介绍了我国反应堆冷中子源现状以及中国科学院在我国国防科学中的作用。