Abstract

A numerical study is conducted for a thermal-hydraulic performance analysis and secondary side screw-type tube inlet orifice design of a once-through steam generator. Various tube-plugging conditions and power levels are considered, and the secondary coolant flow rate is adjusted to maintain a constant level of thermal power. Comprehensive numerical solutions are acquired to evaluate the thermal-hydraulic performance and minimum orifice length of the once-through steam generator under various operating conditions. The results obtained show that constant thermal power can be maintained by properly adjusting the secondary coolant flow rate with variation of the steam outlet superheat degree and secondary coolant pressure drop when the once-through steam generator operates at a high power level. The secondary coolant flow rate curve for constant thermal power operation is determined, and the required minimum orifice length to suppress the flow oscillation below the allowable level is evaluated. The lowest power level results in the highest minimum orifice length, and the non-plugged condition practically limits the orifice length criterion. This orifice length and corresponding pumping power are compared with those when the secondary coolant pressure at the tube outlet is controlled for constant thermal power operation.

摘要

进行了数值研究，以进行直流蒸汽发生器的热工液压性能分析和次级侧螺旋型管入口孔设计。考虑了各种管道堵塞条件和功率水平，并调节了次级冷却液流速，以保持恒定的火力水平。获得了综合的数值解，以评估在各种工况下的直通式蒸汽发生器的热工液压性能和最小孔口长度。获得的结果表明，当直流蒸汽发生器以高功率运行时，通过随着蒸汽出口过热度和二次冷却剂压降的变化而适当地调节二次冷却剂流量，可以保持恒定的热功率。确定用于恒定火力运行的二次冷却剂流量曲线，并评估将流动振荡抑制在允许水平以下所需的最小孔口长度。最低的功率水平导致最大的最小节流孔长度，并且非堵塞状态实际上限制了节流孔长度标准。将该节流孔的长度和相应的泵送功率与控制管出口处的次级冷却液压力以保持恒定的热力运行进行比较。