Recent recognition of colloid and colloidassociated transport of strongly sorbing contaminants in fractured rocks highlights the importance of exploring the transport behavior of colloids under conditions prevailing i...Recent recognition of colloid and colloidassociated transport of strongly sorbing contaminants in fractured rocks highlights the importance of exploring the transport behavior of colloids under conditions prevailing in the field.The rapid transport of colloids through fractured rocks-as affected by the hydraulic properties of the flow system,the properties of fracture surface and the geochemical conditionshas not been sufficiently elucidated,and predictions of colloid transport through fractures have encountered difficulties,particularly at the field scale.This article reviews the current understanding of the mechanisms and modeling of colloid transport and retention in fractured rocks.Commonly used experimental techniques and approaches for conducting colloid transport experiments at different scales,ranging from the laboratory to the field scale,are summarized and commented upon.The importance of various interactions(e.g.,dissolution,colloid deposition,generation,mobilization and deposition of filling materials within fractures) between the flowing solution and the fracture walls(in many cases,with skin or coating on the host rock at the liquid-solid interface) has been stressed.Colloid transport through fractures of high heterogeneity has not yet been well understood and modeled at the field scale.Here,we summarize the current knowledge and understanding accumulated in the last two decades in regard to colloid and colloidassociated transport through fractures.Future research needs are also discussed.展开更多
The solids acceleration length was investigated in a cold dense transport bed （0.10 m-IDx17 m-height） with three kinds of Silica sand. The solids circulation rate （Gs） was up to 954 kg/（m2s）. The effects of oper...The solids acceleration length was investigated in a cold dense transport bed （0.10 m-IDx17 m-height） with three kinds of Silica sand. The solids circulation rate （Gs） was up to 954 kg/（m2s）. The effects of operating conditions, particle properties, and riser structures on the solids acceleration length were investigated under high Gs conditions, with the effect of riser height non-negligible. The solids acceleration length increased with the increase of the riser height. Based on the experimental data, an empirical correlation was proposed to predict the solids acceleration length. Predictions of the correlation were in good agreement with the experimental data in this work and those from the literature over a wide range of Gs （18~954 kg/（m2s））.展开更多
This article is the written version of a lecture given at the Festkolloquium on the occasion of Prof. Dr.-Ing. Dr.techn. E.h. Jtirgen Zierep＇s 80th birthday held at the Universitat Karlsruhe, 21 January 2009. It deal...This article is the written version of a lecture given at the Festkolloquium on the occasion of Prof. Dr.-Ing. Dr.techn. E.h. Jtirgen Zierep＇s 80th birthday held at the Universitat Karlsruhe, 21 January 2009. It deals with laminar viscous inviscid interactions in transonic narrow channel flows. Special emphasis is placed on the internal structure of pseudo-shocks and properties of nozzle flows. Also, it is shown that the theory, first formulated for perfect gases, can easily be extended to the case of general single phase fluids.展开更多
基金supported by the "Hundred Talents Program" of the Chinese Academy of Sciences (No. 724)the National Key Technology R&D Program of the Ministry of Science and Technology of China (No. 2011BAC09B05)+1 种基金the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists(No. 2011T1Z27)the National Natural Science Foundation of China (No. 41171372)
文摘Recent recognition of colloid and colloidassociated transport of strongly sorbing contaminants in fractured rocks highlights the importance of exploring the transport behavior of colloids under conditions prevailing in the field.The rapid transport of colloids through fractured rocks-as affected by the hydraulic properties of the flow system,the properties of fracture surface and the geochemical conditionshas not been sufficiently elucidated,and predictions of colloid transport through fractures have encountered difficulties,particularly at the field scale.This article reviews the current understanding of the mechanisms and modeling of colloid transport and retention in fractured rocks.Commonly used experimental techniques and approaches for conducting colloid transport experiments at different scales,ranging from the laboratory to the field scale,are summarized and commented upon.The importance of various interactions(e.g.,dissolution,colloid deposition,generation,mobilization and deposition of filling materials within fractures) between the flowing solution and the fracture walls(in many cases,with skin or coating on the host rock at the liquid-solid interface) has been stressed.Colloid transport through fractures of high heterogeneity has not yet been well understood and modeled at the field scale.Here,we summarize the current knowledge and understanding accumulated in the last two decades in regard to colloid and colloidassociated transport through fractures.Future research needs are also discussed.
基金the financial support of National High-tech Research and Development Program of China (863 Program) (No. 2006AA05A103)that of Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences (No. KGCX2-YW-348)
文摘The solids acceleration length was investigated in a cold dense transport bed （0.10 m-IDx17 m-height） with three kinds of Silica sand. The solids circulation rate （Gs） was up to 954 kg/（m2s）. The effects of operating conditions, particle properties, and riser structures on the solids acceleration length were investigated under high Gs conditions, with the effect of riser height non-negligible. The solids acceleration length increased with the increase of the riser height. Based on the experimental data, an empirical correlation was proposed to predict the solids acceleration length. Predictions of the correlation were in good agreement with the experimental data in this work and those from the literature over a wide range of Gs （18~954 kg/（m2s））.
文摘This article is the written version of a lecture given at the Festkolloquium on the occasion of Prof. Dr.-Ing. Dr.techn. E.h. Jtirgen Zierep＇s 80th birthday held at the Universitat Karlsruhe, 21 January 2009. It deals with laminar viscous inviscid interactions in transonic narrow channel flows. Special emphasis is placed on the internal structure of pseudo-shocks and properties of nozzle flows. Also, it is shown that the theory, first formulated for perfect gases, can easily be extended to the case of general single phase fluids.
