基于双温度边界格林函数法稳压器喷淋管口热冲击瞬态应力的快速计算

RAPID CALCULATION OF THE THERMAL IMPULSE TRANSIENT STRESS OF THE PRESSURIZER SPRAY NOZZLE BASED ON DOUBLE TEMPERATURE BOUNDARY GREEN’S FUNCTION

一回路核管道受热瞬态载荷作用会在敏感部位造成疲劳损伤,而核电站延寿需要监测这些敏感部位的疲劳累计损伤因子,在线监测时需对敏感部位的热瞬态应力进行快速计算。以稳压器喷淋管口受热冲击为例,采用双温度边界格林函数法进行卷积分,计算了启堆工况瞬态热应力。与有限元直接计算结果进行对比,验证了双温度边界格林函数法温度和应力快速计算的准确性。研究表明,格林函数的建立应根据流动传热边界的不同(如对流传热系数)以及温度区间的宽窄进行区间划分,在不同的区间内建立相应的格林函数。而在某一温度区间内,以该温度区间平均温度为基准并给定足够大的阶跃温度建立格林函数是可行的。

The thermal transient load of the primary loop nuclear pipeline will cause fatigue damage at sensitive locations.And cumulative fatigue damage factors of these sensitive locations need to be monitored during the life extension of the nuclear power plant,and thermal transient stresses need to be calculated rapidly during online monitoring.Taking the thermal shock of the spray nozzle of pressurizer as an example,the double temperature boundary Green’s function method is discussed.By the volume integration of Green’s function,the transient thermal stress under the heat-up condition is calculated.The accuracy of the two temperature boundary Green’s function is verified by comparing with the direct calculation results of finite element method.Studies have shown that the Green’s function should be established separately for subdivisions which are divided according to the differences of the flow heat transfer boundary(such as the convection heat transfer coefficient)and the width of the temperature range.While in a certain temperature range,it is feasible to establish the Green’s function based on the average temperature of the temperature range with large enough step temperature.