【摘要】 流弹性失稳是引起蒸汽发生器传热管管束失效的一种主要原因。在相同流场条件下,传热管是否出现流弹性失稳与其模态频率直接相关。在实际结构中,抗振条对U型传热管弯管段面内支撑机理与面外的方向上不同,是通过摩擦约束实现的。这使得在模态分析计算中,传热管弯管段支撑处的边界条件设置非常重要。本文将传热管与抗振条接触点处的面外边界条件假设为简支,而在面内方向上用弹簧来模拟抗振条对传热管的摩擦约束。同时,通过改变弹簧刚度,讨论了不同强弱的面内支撑对传热管流致振动的影响。分析结果表明,当抗振条与传热管面内接触刚度较弱时,面内流弹性失稳可能较面外流弹性失稳出现得更早。更多还原

【Abstract】 The fluid-elastic instability of heat-transfer tubes is a significant reason that causes tube failures in steam generators.Whether the fluid-elastic instability of a heattransfer tube occurs depends on its modal frequencies.In the actual structure,the in-plane supporting is supplied for the U-band region of the heat-transfer tubes by the anti-vibration bars(AVBs)subjected to friction,and is different from the out-of-plane one in supporting mechanism and direction.This makes the setting of boundary condition at supporting points very important in the modal analysis.In this paper,the out-ofplane boundary conditions were set as simply supported,however,springs were used to simulate the in-plane supporting subjected to the friction between the tubes and AVBs.By changing the stiffness of the springs,the effect of in-plane supporting magnitude on the flow-induced vibration of heat-transfer tubes was discussed.It is indicated that the in-plane fluid-elastic instability may occur earlier than the out-of-plane instability when the contact stiffness between the tube and AVBs is loose.更多还原