瞬变工况下低温流程阀门内空化形成及演化机理研究

As the key control equipment for the transmission of cryogenic medium, cryogenic processing valves are widely used in the transmission systems of cryogenic medium in energy, chemical industry, metallurgy, aerospace engineering and other fields, which plays an important role in the stability and reliability of the system operation. When the flow cross-section is operated in a sudden change, the pressure decreases rapidly at the downstream, which leads to the cavitation in the cryogenic processing valves. Cryogenic cavitation makes serious erosion and damage in the valve core and the pipeline surface, which makes the leakage and noise problems in processing valves. This seriously affects the regulation performance and lifetime of cryogenic processing valves. In this project, theoretical analysis, numerical simulation and experimental studies will be carried out to investigate the cryogenic transient cavitation in model processing valves. By considering the influence of thermodynamic effect and gas compressibility on the cryogenic cavitation, a computational model for accurately calculating cryogenic cavitation is derived. A parameterized characterization method on cryogenic transient cavitation is proposed to reveal the influence of the sudden change of flow cross-section on the cryogenic cavitation in processing valves by analyzing the evolution process of the cryogenic cavitation. The correlation between the cryogenic cavitation and the regulation performance is established by analyzing the transient regulation performance of the model processing valve under cryogenic conditions. The generation and evolution mechanism of cavitation in cryogenic processing valves under transient conditions is obtained based on the above studies.

低温流程阀门作为低温介质输送过程中的关键控制设备，广泛应用于能源、化工、冶金、航空航天等行业低温介质输送系统，对系统运行的稳定性和可靠性起着重要的作用。当低温流程阀门过流断面发生突变时，阀后流场局部区域压力会迅速降低，容易产生低温空化。低温空化会导致流程阀门内产生严重的汽蚀，破坏阀芯和管道表面结构，使阀门产生泄漏和噪声，严重影响流程阀门调控性能和使用寿命。本项目拟采用理论分析、数值模拟和实验研究方法，对流程阀门内低温瞬态空化流动开展研究。考虑热力学效应和可压缩性对低温空化流动的影响，构建精确计算低温空化的计算模型；分析阀门内空化的动态变化过程，提出低温瞬态空化参数化表征方式，揭示过流断面突变对程阀门内低温空化流动的影响规律；分析低温工况下流程阀门瞬态调控特性变化规律，建立低温空化流动与调控性能参数之间的关联规律，揭示瞬变工况下低温流程阀门内空化形成及演化机理。

低温流程阀门作为低温介质输送过程中的关键控制设备，广泛应用于能源、化工、航空航天等行业低温介质输送系统，对系统运行的稳定性和可靠性起着重要的作用。当低温流程阀门过流断面发生突变时，阀后流场局部区域压力会迅速降低，容易产生低温空化，由空化引起的空蚀破坏是导致低温阀门泄露，甚至失效的主要原因。本项目针对蝶阀内部低温空化流动进行了理论分析、数值模拟及实验研究，构建了基于热力学效应和可压缩效应的流程阀门低温空化数值计算模型，并开展不同流动及结构参数下蝶阀低温空化流动数值计算；分析了低温蝶阀内空化产生、发展及溃灭动态演变过程，获得了蝶阀内空化周期性演变规律及蝶板附着空化动态演变规律，建立了阀内低温空化与旋涡之间的关联关系；提取了低温蝶阀内部总熵产分布，揭示了蝶阀低温空化与熵产之间的关联关系；分析了蝶板启闭动作速度对蝶阀内部空化演变的影响，揭示了蝶阀启闭过程阀内空化动态演变的迟滞效应，为低温流程阀门空化抑制结构设计提供理论依据和技术支撑。