The computational fluid dynamics （CFD）-population balance equations （PBE） coupled model is employed to investigate the hydrodynamics in a gas-slurry internal loop reactor with external slurry circulation. The pred...The computational fluid dynamics （CFD）-population balance equations （PBE） coupled model is employed to investigate the hydrodynamics in a gas-slurry internal loop reactor with external slurry circulation. The predicted radial profiles of local gas holdup and bubble diameter are in good agreement with the corresponding experimental data. The spatio-temporal velocity profile of the gas phase reveals that the upward movement of gas is slowed down and the residence time of gas is prolonged by the downward momentum of the slurry, introduction of the external slurry can greatly improve the uniformity of gas holdup distribution in the reactor, especially in the downcomer-tube action region. Moreover, the interaction between the downward slurry and upward gas can lead to small bubble size and high interfacial area as well as good mass and heat transfer. The above results suggest the function of external slurry circulation for the internal loop reactor and would be helpful for optimizing the design and scale up of reactors.展开更多
Robotics is one area of research in which bio-inspiration is an effective way to design a system by investigating the working principles of nature. Recently, tails have received interest in robotics to increase stabil...Robotics is one area of research in which bio-inspiration is an effective way to design a system by investigating the working principles of nature. Recently, tails have received interest in robotics to increase stability and maneuverability. In this study, we investigated the effectiveness of a static tail for bio-inspired water-running locomotion. The tail was added to increase the stability in the rolling and yawing directions based on the hydrodynamic force from interaction between the tail and the water. The drag coefficient in the interaction is not easy to calculate analytically, so experimental studies were done for various static tail shapes. Five different shapes and compliances in two directions were considered for experimental design candidates. The result was applied to design a stable amphibious robot that can run on ground and water surfaces.展开更多
基金Financial support from the National Natural Science Foundation of China(51076043 and 51061130538)Program for New Century Excellent Talents in University(NCET-09-0342)+1 种基金Central Universities(12QN02)111 Project(B12034)
文摘The computational fluid dynamics （CFD）-population balance equations （PBE） coupled model is employed to investigate the hydrodynamics in a gas-slurry internal loop reactor with external slurry circulation. The predicted radial profiles of local gas holdup and bubble diameter are in good agreement with the corresponding experimental data. The spatio-temporal velocity profile of the gas phase reveals that the upward movement of gas is slowed down and the residence time of gas is prolonged by the downward momentum of the slurry, introduction of the external slurry can greatly improve the uniformity of gas holdup distribution in the reactor, especially in the downcomer-tube action region. Moreover, the interaction between the downward slurry and upward gas can lead to small bubble size and high interfacial area as well as good mass and heat transfer. The above results suggest the function of external slurry circulation for the internal loop reactor and would be helpful for optimizing the design and scale up of reactors.
文摘Robotics is one area of research in which bio-inspiration is an effective way to design a system by investigating the working principles of nature. Recently, tails have received interest in robotics to increase stability and maneuverability. In this study, we investigated the effectiveness of a static tail for bio-inspired water-running locomotion. The tail was added to increase the stability in the rolling and yawing directions based on the hydrodynamic force from interaction between the tail and the water. The drag coefficient in the interaction is not easy to calculate analytically, so experimental studies were done for various static tail shapes. Five different shapes and compliances in two directions were considered for experimental design candidates. The result was applied to design a stable amphibious robot that can run on ground and water surfaces.
