水平加热管束间三维汽液两相流特性的研究

针对卧式火管式蒸汽发生器的结构特点，对水平加热管束间的三维汽液两相流特性进行了实验研究。用单探头和三探头单纤光导探针分别测定了加热管束间的空泡份额分布和汽相速度分布。开发了三维汽液两相低雷诺数湍流漂移数学模型和相应的数值计算方法。为计算漂移数学模型中的汽相速度，综合考虑了重力和流体本身的加速作用对汽相漂移速度的影响，故该漂移数学模型可用于分析多维汽液两相流。计算结果与实验测量值符合良好，证明该数学模型是正确可靠的。

Three-dimensional two-phase flow in horizontal heated tube bundles

Three dimensional two phase flow in horizontal heated tube bundles has been investigated experimentally and simulated numerically. In the experiments, a single fibre optical probe was developed to measure the local void fraction and a tri fibre optical probe was developed to measure the vapor bubble velocities inside the heated tube bundles. A mathematical model of three dimensional two phase low Reynolds number turbulent flow was developed based on the modified drift flux model and the internal circulation characteristics of the two phase flow in the tube bundles. A numerical simulation method was also developed to analyze the two phase flow structures. In the modified drift flux model both the acceleration by gravity and the acceleration of the average volumetric flow were taken into account for the calculation of the drift velocities. The modified drift flux model could then be applied to the analysis of multi dimensional two phase flows. The predicted distributions of the vapor phase velocity, the liquid phase velocity and the void fraction were agreed reasonably well with the experimental results. The results confirm that the modified drift flux model can correctly simulate three dimensional two phase flow.