An electrically activated underwater suction device is designed to form an amazing amount of negative pressure by generating water swirling flow,which can make underwater wall-climbing robot stick to the wall surface ...An electrically activated underwater suction device is designed to form an amazing amount of negative pressure by generating water swirling flow,which can make underwater wall-climbing robot stick to the wall surface allowing a ground clearance.For the purpose of a full understanding of the mechanism of the suction device,a series of experimental tests are carried out and a computational fluid dynamics(CFD)model is established.The results show that the suction force F is consistent between experimental tests and simulations.An insight into the flow phenomena of vortex suction device,including spatial velocity and pressure distribution,is given through numerical simulation analysis.Furthermore,the crucial parameters,i.e.,the rotation speedωand gap clearance h,are studied.Then the relationships of F-ωand F-h are clarified.It reveals that with the increasing of rotation speed,the suction force increases quadratically.And with the increasing of gap clearance,the suction force increases firstly and then decreases,so that a reasonable design interval of gap clearance can be got to obtain the required suction force for the engineering applications.展开更多
At the late stage of continuous casting（CC）ladle teeming,sink vortex can suck the liquid slag into tundish,and cause negative influences on the cleanliness of molten steel.To address this issue,a twophase fluid mech...At the late stage of continuous casting（CC）ladle teeming,sink vortex can suck the liquid slag into tundish,and cause negative influences on the cleanliness of molten steel.To address this issue,a twophase fluid mechanical modeling method for ladle teeming was proposed.Firstly,a dynamic model for vortex suction process was built,and the profiles of vortex flow field were acquired.Then,based on the level set method（LSM）,a two-phase 3Dinterface coupling model for slag entrapment was built.Finally,in combination with high-order essentially non-oscillatory（ENO）and total variation diminishing（TVD）methods,a LSM-based numerical solution method was proposed to obtain the 3Dcoupling evolution regularities in vortex suction process.Numerical results show that the vortex with higher kinetic energy can form an expanded sandglass-shape region with larger slag fraction and lower rotating velocity;there is a pressure oscillation phenomenon at the vortex penetration state,which is caused by the energy shock of two-phase vortex penetration coupling.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11672105)the Natural Science Foundation of Hunan Province(Grant No.2016JJ1009)。
文摘An electrically activated underwater suction device is designed to form an amazing amount of negative pressure by generating water swirling flow,which can make underwater wall-climbing robot stick to the wall surface allowing a ground clearance.For the purpose of a full understanding of the mechanism of the suction device,a series of experimental tests are carried out and a computational fluid dynamics(CFD)model is established.The results show that the suction force F is consistent between experimental tests and simulations.An insight into the flow phenomena of vortex suction device,including spatial velocity and pressure distribution,is given through numerical simulation analysis.Furthermore,the crucial parameters,i.e.,the rotation speedωand gap clearance h,are studied.Then the relationships of F-ωand F-h are clarified.It reveals that with the increasing of rotation speed,the suction force increases quadratically.And with the increasing of gap clearance,the suction force increases firstly and then decreases,so that a reasonable design interval of gap clearance can be got to obtain the required suction force for the engineering applications.
基金supported by NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(U1509212)National Natural Science Foundation of China(51375446)Zhejiang Provincial Natural Science Foundation for Distinguished Young Scientists(LR16E050001)
文摘At the late stage of continuous casting（CC）ladle teeming,sink vortex can suck the liquid slag into tundish,and cause negative influences on the cleanliness of molten steel.To address this issue,a twophase fluid mechanical modeling method for ladle teeming was proposed.Firstly,a dynamic model for vortex suction process was built,and the profiles of vortex flow field were acquired.Then,based on the level set method（LSM）,a two-phase 3Dinterface coupling model for slag entrapment was built.Finally,in combination with high-order essentially non-oscillatory（ENO）and total variation diminishing（TVD）methods,a LSM-based numerical solution method was proposed to obtain the 3Dcoupling evolution regularities in vortex suction process.Numerical results show that the vortex with higher kinetic energy can form an expanded sandglass-shape region with larger slag fraction and lower rotating velocity;there is a pressure oscillation phenomenon at the vortex penetration state,which is caused by the energy shock of two-phase vortex penetration coupling.
