负压分布规律是真空预压机理研究的重要课题。通过讨论真空预压负压空间分布特点及负压相关概念,广义地定义了负压,分析了负压的测量方法及影响因素。设计高15.0 m的竖向大比尺室内模型,开展真空预压负压分布规律试验研究。试验结果表明...负压分布规律是真空预压机理研究的重要课题。通过讨论真空预压负压空间分布特点及负压相关概念,广义地定义了负压,分析了负压的测量方法及影响因素。设计高15.0 m的竖向大比尺室内模型,开展真空预压负压分布规律试验研究。试验结果表明,饱和黏土土中真空度测量存在滞后效应,本次试验真空度存在的极限深度为8.9 m;膜下真空度稳定后,零压面之上孔压及板中真空度沿深度呈对称线性分布,斜率均近似为静水压力梯度;负压沿深度为分段线性分布,在地下水位之上的非饱和段因提水做功而衰减,稳定期负压平均衰减值为21.4 k Pa,在水位之下排水板埋深范围内基本均匀分布而无衰减,稳定期平均负压为-67.0 k Pa。结合试验规律及等效排水管中气液两相流的流型分布,给出了真空预压稳定期竖向排水板中的分段线性负压边界。展开更多
Numerical simulations are performed both for the single airflow and air-PMtwo-phase flow in wall flow diesel participate filters (DPF) for the first time. The calculationdomain is divided into two regions. In. the inl...Numerical simulations are performed both for the single airflow and air-PMtwo-phase flow in wall flow diesel participate filters (DPF) for the first time. The calculationdomain is divided into two regions. In. the inlet and outlet flow channels, the simulations areperformed for the steady and laminar flow; In the porous filtration walls, the calculation model forflow in porous media is used. The Lagrange two-phase flow model is used to calculate the air-PMflow in DPF, for the dispersed phase (PM), its flow tracks are obtained by the integrating of theLagrange kinetic equation. The calculated velocity, pressure distribution and PM flow tracks in DPFare obtained, which exhibits the main flow characteristics in wall flow DPF and will be help for theoptimal design and performance prediction of wall flow DPF.展开更多
文摘负压分布规律是真空预压机理研究的重要课题。通过讨论真空预压负压空间分布特点及负压相关概念,广义地定义了负压,分析了负压的测量方法及影响因素。设计高15.0 m的竖向大比尺室内模型,开展真空预压负压分布规律试验研究。试验结果表明,饱和黏土土中真空度测量存在滞后效应,本次试验真空度存在的极限深度为8.9 m;膜下真空度稳定后,零压面之上孔压及板中真空度沿深度呈对称线性分布,斜率均近似为静水压力梯度;负压沿深度为分段线性分布,在地下水位之上的非饱和段因提水做功而衰减,稳定期负压平均衰减值为21.4 k Pa,在水位之下排水板埋深范围内基本均匀分布而无衰减,稳定期平均负压为-67.0 k Pa。结合试验规律及等效排水管中气液两相流的流型分布,给出了真空预压稳定期竖向排水板中的分段线性负压边界。
文摘Numerical simulations are performed both for the single airflow and air-PMtwo-phase flow in wall flow diesel participate filters (DPF) for the first time. The calculationdomain is divided into two regions. In. the inlet and outlet flow channels, the simulations areperformed for the steady and laminar flow; In the porous filtration walls, the calculation model forflow in porous media is used. The Lagrange two-phase flow model is used to calculate the air-PMflow in DPF, for the dispersed phase (PM), its flow tracks are obtained by the integrating of theLagrange kinetic equation. The calculated velocity, pressure distribution and PM flow tracks in DPFare obtained, which exhibits the main flow characteristics in wall flow DPF and will be help for theoptimal design and performance prediction of wall flow DPF.