降温过程中LNG板翅结构应力耦合模拟

Numerical investigation on stress of plate-fin structures during cool-down of LNG heat exchanger

摘要:

为保证大型LNG冷箱降温过程中板翅式换热器结构安全可靠,建立了板翅结构应力耦合分析模型,采用热-结构直接耦合模拟方法,分析了降温过程对板翅结构应力的影响规律. 结果表明：翅片和隔板钎焊接头处为结构最易破坏区；温差对板翅结构应力影响较为明显,并随温差增大而增大；当温差小于10 K时,对流换热性能对板翅结构应力影响较小；当温差相等时,降温速率对板翅结构应力影响较小. 

Abstract:

In order to ensure the structural safety of plate-fin heat exchanger, a model was proposed to simulate the stress of plate-fin structures in the cool-down process. The stress of plate-fin structures was investigated in the cool-down process based on directly coupled Finite Element Method. The results showed that the most easily damaged area happened in the brazed joint between fin and plate in the cool-down process. At the same time, the stress was obviously influenced by the temperature difference between natural gas (NG) and mixture refrigerant (MR) and increased with increasing temperature difference. The heat transfer performance had little influence on the stress of plate-fin structures when the temperature difference between NG and MR was less than 10 K. The stress of plate-fin structures was also slightly impacted by the temperature drop rate as the temperature drop rate of NG was the same as that of MR in the cool-down process.