铅铋快堆螺旋管直流蒸汽发生器热工水力特性数值研究

Numerical Investigation on Thermal Hydraulics of Helical Coil Tube Once Through Steam Generator for LBE Fast Reactor

本研究以铅铋快堆螺旋管直流蒸汽发生器(HOTSG)设计结构为研究对象,采用精细网格与多孔介质相结合的物理建模方法,通过一次侧三维湍流计算与二次侧用户自定义函数(UDF)分区传热计算相耦合的手段,在FLUENT求解器中开展了蒸汽发生器的热工水力特性数值分析研究。研究表明:铅铋入口附近的流量分配孔和腔室对应的直管段区域出现铅铋流速峰值,径向最大速度为0.431 m/s;入口腔室至管束区位置受到阻力突变的影响,压力、横流速度、轴向速度变化较大;热工参数变化符合流动与传热机理,临界热流密度(CHF)点附近一二次侧温差最大为109.61 K,此处最大热流密度为323.55 kW/m^(2)。该研究将为铅铋快堆HOTSG结构设计、流致振动及安全评价提供重要的参考。

The design of Lead and Bismuth Eutectic(LBE)cooled fast reactor helical coil tube steam generator is modeled in this study.Physical modeling method is developed with the combination of fine grid blocks and porous medium.Through the coupling the primary three-dimensional turbulence calculation and the secondary side heat transfer based on UDF(User Defined Function)method,a numerical analysis of the thermal hydraulic characteristics of the steam generator is carried out in the FLUENT solver.The results show that:a.the flow distribution holes near LBE inlet and the straight tubes in the chamber have peaks in the flow rate of LBE,and the maximum radial velocity is 0.431 m/s,b.when LBE flows from the inlet chamber into the tube bundle,the pressure,cross flow and axial flow rates change rapidly because of resistance mutation,and c.the changing process of thermal hydraulic parameters confirms to the qualitative mechanism analysis results of flow and heat transfer.The maximum temperature difference between primary and secondary sides near the Critical Heat Flux(CHF)point is 109.61 K,and the maximum heat flux is 323.55 kW/m^(2).This study will provide an important reference for HOTSG structure design,fluid-induced vibration and safety evaluation of lead-bismuth fast reactor.