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
Numerical simulations using CLSVOF(coupled level set and volume of fluid)method are performed to investigate the coalescence and splashing regimes when a spherical water drop hits on the water surface with an impingem...Numerical simulations using CLSVOF(coupled level set and volume of fluid)method are performed to investigate the coalescence and splashing regimes when a spherical water drop hits on the water surface with an impingement angle.Impingement angle is the angle between the velocity vector of primary drop and the normal vector to water surface.The effect of impingement angle,impact velocity and the height of target liquid are carried out.The impingement angle is varied from 0o to 90o showing the gradual change in phenomena.The formation of ship pro like shape,liquid sheet,secondary drops and crater are seen.Crater height,crater displacement,crown height and crown angle are calculated and the change in the parameters with change in impingement angle is noted.展开更多
The Large Eddy Simulation （LES） of the wave breaking over a muddy seabed is carried out with a Coupled Level Set and Volume Of Fluid （CLSVOF） method to capture the interfaces.The effects of the mud on the wave bre...The Large Eddy Simulation （LES） of the wave breaking over a muddy seabed is carried out with a Coupled Level Set and Volume Of Fluid （CLSVOF） method to capture the interfaces.The effects of the mud on the wave breaking are studied.The existence of a mud layer beneath an otherwise rigid bottom is found to have a similar effect as an increase of the water depth.As compared with the case of a simple rigid bottom,the inception of the wave breaking is evidently delayed and the breaking intensity is much reduced.The dissipation of the wave energy is shown to have very different rates before,during and after the breaking.Before and after the breaking,the mud plays an important role.During the breaking,however,the turbulence as well as the entrainment of the air also dissipate a large amount of energy.展开更多
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.
文摘Numerical simulations using CLSVOF(coupled level set and volume of fluid)method are performed to investigate the coalescence and splashing regimes when a spherical water drop hits on the water surface with an impingement angle.Impingement angle is the angle between the velocity vector of primary drop and the normal vector to water surface.The effect of impingement angle,impact velocity and the height of target liquid are carried out.The impingement angle is varied from 0o to 90o showing the gradual change in phenomena.The formation of ship pro like shape,liquid sheet,secondary drops and crater are seen.Crater height,crater displacement,crown height and crown angle are calculated and the change in the parameters with change in impingement angle is noted.
基金Project supported by the National Natural Science Foundation of China (Grant No.51109119)the State key Laboratory of Hydro-science and Engineering,Tsinghua University (Grant No.2011-KY-1)
文摘The Large Eddy Simulation （LES） of the wave breaking over a muddy seabed is carried out with a Coupled Level Set and Volume Of Fluid （CLSVOF） method to capture the interfaces.The effects of the mud on the wave breaking are studied.The existence of a mud layer beneath an otherwise rigid bottom is found to have a similar effect as an increase of the water depth.As compared with the case of a simple rigid bottom,the inception of the wave breaking is evidently delayed and the breaking intensity is much reduced.The dissipation of the wave energy is shown to have very different rates before,during and after the breaking.Before and after the breaking,the mud plays an important role.During the breaking,however,the turbulence as well as the entrainment of the air also dissipate a large amount of energy.
