部分充液下液力偶合器内部介质运动为离心力场作用下的复杂两相流动,而液相分布形态对涡轮输出特性有着直接影响。为掌握偶合器内液相分布规律,将工作腔内介质运动视为分层流动,采用流体体积法(Volume of fluid,VOF)两相流模型,追踪562...部分充液下液力偶合器内部介质运动为离心力场作用下的复杂两相流动,而液相分布形态对涡轮输出特性有着直接影响。为掌握偶合器内液相分布规律,将工作腔内介质运动视为分层流动,采用流体体积法(Volume of fluid,VOF)两相流模型,追踪562型标准桃形腔偶合器内不同工况下的气—液分界面。建立三维周期性流道模型,采用Realizable k-ε湍流模型和压力隐式算子分裂(Pressure-implicit with splitting of operators,PISO)压力耦合算法,并用内部面模拟泵、涡轮间的交互作用,转速比i=1.0和i=0.6时的叶片表面液相分布与文献中试验结果具有高度相似性。仿真结果表明,随泵涡轮间转差增大,气液分界面倾斜加剧,直至形成大的环流,而泵轮叶片压力面液相分布区域增大,吸力面液相减小;低挡圈(R=155 mm)对环流形态影响较小,主要起到限矩作用,而高挡圈(R=175 mm)可抑制大环流的产生。展开更多
The formed characteristics of thin-wall part is studied when it is in the process of MPAW. Finite element method is used to sinmlate the temperature field coupling flow field in the welding of thin-wall part. It is fo...The formed characteristics of thin-wall part is studied when it is in the process of MPAW. Finite element method is used to sinmlate the temperature field coupling flow field in the welding of thin-wall part. It is found that because of the obvious effect of heat accumution in cross-section, where the distribution of temperature field area presents trapezoidal inverted approximately in the molten pool and the non-molten pool area presents level. The surface tension, the electromagnetic force and buoyancy are considered for analyzing the effects on the fluid flow of welding-pool. It can be obtained that the surface tension is the main driving force in the welding pool, which is far greater than electromagnetic force and buoyancy.展开更多
文摘部分充液下液力偶合器内部介质运动为离心力场作用下的复杂两相流动,而液相分布形态对涡轮输出特性有着直接影响。为掌握偶合器内液相分布规律,将工作腔内介质运动视为分层流动,采用流体体积法(Volume of fluid,VOF)两相流模型,追踪562型标准桃形腔偶合器内不同工况下的气—液分界面。建立三维周期性流道模型,采用Realizable k-ε湍流模型和压力隐式算子分裂(Pressure-implicit with splitting of operators,PISO)压力耦合算法,并用内部面模拟泵、涡轮间的交互作用,转速比i=1.0和i=0.6时的叶片表面液相分布与文献中试验结果具有高度相似性。仿真结果表明,随泵涡轮间转差增大,气液分界面倾斜加剧,直至形成大的环流,而泵轮叶片压力面液相分布区域增大,吸力面液相减小;低挡圈(R=155 mm)对环流形态影响较小,主要起到限矩作用,而高挡圈(R=175 mm)可抑制大环流的产生。
基金supported by the National Natural Science Foundation of China(Grant No.U1333128,U1733125)Science and Technology Project of Tianjin(Grant No.14ZCDZGX00802,17JCZDJC38700)
文摘The formed characteristics of thin-wall part is studied when it is in the process of MPAW. Finite element method is used to sinmlate the temperature field coupling flow field in the welding of thin-wall part. It is found that because of the obvious effect of heat accumution in cross-section, where the distribution of temperature field area presents trapezoidal inverted approximately in the molten pool and the non-molten pool area presents level. The surface tension, the electromagnetic force and buoyancy are considered for analyzing the effects on the fluid flow of welding-pool. It can be obtained that the surface tension is the main driving force in the welding pool, which is far greater than electromagnetic force and buoyancy.
