曲率对竖直向上环形狭窄通道内环状流特性的影响

基于三流体分离流模型，以液膜质量、动量和能量守恒方程为基础，结合汽芯动量方程，对双面加热垂直向上流动环形狭窄通道内环状流特性进行数值模拟。将计算结果与实验结果相比较，两者符合较好。通过数值模拟，分析了曲率对环状流特性的影响，得到了曲率对液膜厚度、液膜内温度、液膜内速度、临界热流密度等的影响曲线。曲率越大，内液膜越薄，而外液膜越厚。内管干涸时，临界热流密度随曲率的减小而增大；外管干涸时，则反之。

Effects of Curvature on Characteristics for Annular Flow in Vertical Narrow Annular Gap

Based on the separated flow model, a mathematical model for annular upward flow in vertical narrow annuli with bilateral heating was developed. The theoretical model is based on the mass, momentum, and energy conservation equations of liquid films and the momentum conservation equation of the vapor core. The predicted results agree with the experimental data very well. By numerically solving the equations, the influences of curvature on the characteristics of annular upward flow, including liquid film thickness, temperature and velocity distribution in liquid films and critical heat flux, were obtained. The thickness of inner liquid film decreases with an increase in curvature, while the thickness of outer liquid film increases with curvature. When the dryout point occurs on the inner tube, the critical heat flux will increase with the decrease of curvature. And the case reverses when the dryout point occurs on the outer tube.