摘要
为保证LNG板翅式换热器冷箱安全运行,建立了板翅结构热应力有限元耦合分析物理模型,采用热-力直接耦合方法分析了大型LNG板翅式换热器冷箱正常运行时板翅结构的热应力分布规律,分析结果表明:实际运行工况下板翅结构的第一主应力、第三主应力以及基于第三强度理论的等效应力在钎焊位置处变化梯度较大,并且等效应力最大值出现在翅片和隔板钎焊位置处,从而使钎焊位置可能发生疲劳破坏;对于整个板翅结构,结构最薄弱区在最外层隔板与翅片的钎焊位置处。上述研究成果将为大型LNG冷箱内板翅式换热器结构设计和安全可靠运行提供重要参考依据。
In order to ensure the safe operation of large-scale cold-box,a finite element model （FEM） based on thermal elastic theory was proposed to simulate thermal stress distribution of plate-fin structure in large LNG cold box under the normal operating conditions.Thermal-stress direct coupling method was adopted in this analysis.By the thermal stress distribution in four paths marked in the structure,it is found that,in actual operating conditions,the first principal stress and the third principal stress reach to maximum value in brazed joint,the stress gradient is larger than that of other region and a crack would be occurred in this region.And the equivalent thermal stress based on third strength theory was also calculated in four paths.The result is consistent with the simulation results.Meanwhile,it also concluded that the most dangerous region is the outermost brazed joint between plate and fin for the whole plate-fin structure.These results will provide some constructive instructions in the design and safe operation for large-scale LNG cold-box.
出处
《节能技术》
CAS
2014年第4期291-294,304,共5页
Energy Conservation Technology
基金
国家高技术研究发展计划(863计划)(2013AA09A216)
