基于OLGA的二氧化碳管道意外泄漏减压特性模拟可靠性

Simulation reliability of accidental decompression characteristics released from carbon dioxide pipeline with OLGA software

为探究OLGA软件能否用于模拟超临界二氧化碳管道意外泄漏减压特性这一问题,基于DN 250、长258 m的工业规模超临界二氧化碳管道意外泄漏试验,采用OLGA软件建立了与试验工况一致的模拟模型,得到50 mm、100 mm、233 mm(全口径)泄漏口径时,管线内不同位置二氧化碳压力、温度随时间的变化,探讨OLGA软件模拟二氧化碳管道意外泄漏减压的可靠性。结果表明:OLGA模拟模型用于预估泄漏减压持续时间具有较好可靠性;OLGA模拟模型无法预测意外泄漏瞬间的减压波传播行为;OLGA模拟模型预测得到的泄漏口径233 mm的超临界二氧化碳泄漏压降及温降与试验结果有显著偏差;OLGA模拟模型在一定程度上能够再现泄漏口径为50 mm、100 mm时超临界二氧化碳泄漏压降及温降行为,可应用于精度要求不太高的工程预测场合。

A one-dimensional geometric model consistent with the experimental conditions was established using commercial software OLGA,based on the supercritical carbon dioxide accidental leakage experiments from DN 250,a 258 m long industrial scale pipeline performed previously.The materials,thickness,and thermos-dynamic properties of the pipe wall and insulation layer were set in the model.The leak boundary condition was applied to the model to simulate the carbon dioxide accidental leakage process.The properties of carbon dioxide calculated by the SRK-Peneloux equation were imported to the model by PVTsim 20 software.The unsteady calculation method was set to the model.The variations of pressures and temperatures at different locations in the pipeline were calculated at different relief diameters of 50 mm,100 mm,and 233 mm(full bore rupture).The reliability of OLGA simulation was explored by comparing the simulated results with experimental ones.The results show that,in all these three conditions at different relief diameters,the predicted duration time of leakage is nearly the same as the experimental values,indicating that OLGA simulation has good reliability in predicting the duration of leakage;At the onset of accidental release,the pressure sudden drop and rebound due to decompression wave propagation shown in experiments is not occurred in numerical results,indicating that OLGA simulation cannot predict the propagation behavior of pressure decompression waves.During the pressure decompression process with a leakage diameter of 233 mm,the simulated pressure drop and temperature drop are significantly different from the experimental results,indicating that OLGA simulation cannot be applied to predict pressure drop and temperature drop at full bore rupture condition;OLGA simulation can reproduce the pressure drop and temperature drop law of supercritical carbon dioxide leakage when the leakage technique is 50 mm and 100 mm to a certain extent,and can be applied to engineering occasions with low precision requirements.