To reduce the temperature gradient of the flange and thus reduce the stress,a structural optimization scheme is proposed to embed a heat-resistant ring inside the flange(the thermal heat-resistant ring is covered by pure nickel and filled with aerogel with very low thermal conductivity)for the problems such as high stress at the center hole and easy to develop cracks when the freeze flange for molten salt reactor is in use.The effect of flange neck thickness on the maximum stress at the flange seal and the temperature,and the effect of tensile directions(flange receiver direction and radial direction)on the maximum stress of the flange were investigated to reduce the mass and size of the flange based on the reduction of flange stress.The temperature,stress and creep fatigue damage of the flange were calculated by the finite element method.The results show that the built-in thermal heat-resistant ring of the flange can reduce the temperature gradient and thus reduce the flange stress,the stress at the flange seal and the temperature decrease with the reduction of the flange neck thickness and stretching the flange along the receiver direction can reduce the maximum flange stress.The mass and sizes of the flange in the final optimized solution are significantly reduced,and the weight reduction effect is obvious,meeting the requirements of ASME NH high temperature assessment.
关键词
冷冻法兰/熔盐堆/应力评定/结构优化/有限元分析
Key words
freeze flange/molten salt reactor/stress evaluation/structure optimization/finite element analysis
维普
万方数据