Plasma jet triggered gas gap switch has obvious advantages in fast control switch.The development of the plasma in the ambient medium is the key factor affecting the triggering conduction of the gas switch.However,the...Plasma jet triggered gas gap switch has obvious advantages in fast control switch.The development of the plasma in the ambient medium is the key factor affecting the triggering conduction of the gas switch.However,the plasma jet process and its characteristic parameters are complicated and the existing test methods cannot fully characterize its development laws.In this work,a two-dimensional transient fluid calculation model of the plasma jet process of the gas gap switch is established based on the renormalization-group k-εturbulence equation.The results show that the characteristic parameters and morphological evolution of the plasma jet are basically consistent with the experimental results,which verifies the accuracy of the simulation model calculation.The plasma jet is a long strip with an initial velocity of 1.0 km·s-1and develops in both axial and radial directions.The jet velocity fluctuates significantly with axial height.As the plasma jet enters the main gap,the pressure inside the trigger cavity drops by80%,resulting in a rapid drop in the jet velocity.When the plasma jet head interacts with the atmosphere,the two-phase fluid compresses each other,generating a forward-propelled pressure wave.The plasma jet heads flow at high velocity,a negative pressure zone is formed in the middle part of the jet,and the pressure peak decreases gradually with height.As the value of the inlet pressure increases,the characteristic parameters of the plasma jet increase.The entrainment phenomenon is evident,which leads to an increase in the pressure imbalance of the atmospheric gas medium,leading to a significant Coanda effect.Compared with air,the characteristic parameters of a plasma jet in SF6are lower,and the morphological evolution is significantly suppressed.The results of this study can provide some insight into the mechanism of action of the switch jet plasma development process.展开更多
海上装配式输油管道通常是用连接器将各管段连接而成,其连接器的抗弯、抗拉能力与管道本体有很大的差异。通过Solid Works建立管道连接处的分析模型,计算管道能够承受的最大正应力和最大弯矩,利用有限元分析软件Solid Works Simulation...海上装配式输油管道通常是用连接器将各管段连接而成,其连接器的抗弯、抗拉能力与管道本体有很大的差异。通过Solid Works建立管道连接处的分析模型,计算管道能够承受的最大正应力和最大弯矩,利用有限元分析软件Solid Works Simulation分析管道连接处的抗弯强度和抗拉强度,为管道连接器的优化设计提供依据,为工程设计提供参考。分析结果表明:加强连接器的强度不低于管道本体强度,整个管道系统没有出现强度薄弱的地方,满足安全要求。展开更多
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0304-02)Joint Chinese Academy of Sciences(CAS)-Max Planck Society(MPG)Research Project(HZXM20225001MI)+3 种基金the Strategic Priority Research Program A of Chinese Academy of Sciences(XDA20050104)the National Natural Science Foundation of China(42041005)CAS Light of West China Programthe Fundamental Research Funds for the Central Universities。
基金supported by National Natural Science Foundation of China(No.52107142)。
文摘Plasma jet triggered gas gap switch has obvious advantages in fast control switch.The development of the plasma in the ambient medium is the key factor affecting the triggering conduction of the gas switch.However,the plasma jet process and its characteristic parameters are complicated and the existing test methods cannot fully characterize its development laws.In this work,a two-dimensional transient fluid calculation model of the plasma jet process of the gas gap switch is established based on the renormalization-group k-εturbulence equation.The results show that the characteristic parameters and morphological evolution of the plasma jet are basically consistent with the experimental results,which verifies the accuracy of the simulation model calculation.The plasma jet is a long strip with an initial velocity of 1.0 km·s-1and develops in both axial and radial directions.The jet velocity fluctuates significantly with axial height.As the plasma jet enters the main gap,the pressure inside the trigger cavity drops by80%,resulting in a rapid drop in the jet velocity.When the plasma jet head interacts with the atmosphere,the two-phase fluid compresses each other,generating a forward-propelled pressure wave.The plasma jet heads flow at high velocity,a negative pressure zone is formed in the middle part of the jet,and the pressure peak decreases gradually with height.As the value of the inlet pressure increases,the characteristic parameters of the plasma jet increase.The entrainment phenomenon is evident,which leads to an increase in the pressure imbalance of the atmospheric gas medium,leading to a significant Coanda effect.Compared with air,the characteristic parameters of a plasma jet in SF6are lower,and the morphological evolution is significantly suppressed.The results of this study can provide some insight into the mechanism of action of the switch jet plasma development process.
文摘海上装配式输油管道通常是用连接器将各管段连接而成,其连接器的抗弯、抗拉能力与管道本体有很大的差异。通过Solid Works建立管道连接处的分析模型,计算管道能够承受的最大正应力和最大弯矩,利用有限元分析软件Solid Works Simulation分析管道连接处的抗弯强度和抗拉强度,为管道连接器的优化设计提供依据,为工程设计提供参考。分析结果表明:加强连接器的强度不低于管道本体强度,整个管道系统没有出现强度薄弱的地方,满足安全要求。
