Investigation On Flow And Heat Transfer Characteristics And Electromagnetic Force Control Of Cylindrical Flow

The phenomenon of flow around the cylinder is common in engineering applications and daily lifes.It is essentially a coupling between fluid and solid force by interaction of forces.It carried out extensive research by the scientific community because of complex and profound physical mechanisms.Useing various factors to affect the vibration of the cylinder is an important research direction of the flow around the cylinder,which can promot fluid mixing and improve heat transfer performance.It is very practical and has scientific research value,which can provide new research ideas for the field of stirring and strengthening heat exchange.This paper presents numerical method to study the process of flow around elliptic cylinders under the condition of pulsating flow,the process of cylindrical vortex-induced vibration under the condition of pulsating flow,and the active control process of the flow around cylinder by electromagnetic force.The flow field characteristics,spectrum characteristics and heat transfer characteristics are analyzed.The major conclusions are the following.(1)For the flow around an elliptic cylinder under pulsating flow condition,with the axial length ratio and pulsation amplitude changing,the distribution of the elliptic cylinder tail vortex change.As the axis length ratio of the ellipse increases,the vortex shedding speed decreases and the vibration of the elliptic cylinder increases.Under Low-Reynold number conditions,the type of heat transfer around the pulsating elliptic cylinder is dominated by stable convective heat transfer.With the increase of axial length ratio,the local maximum heat transfer capacity of elliptic cylinder wall decreases.The overall heat transfer performance increases.(2)For cylindrical vortex-induced vibration under conditions of pulsating flow,the vibration mode of the cylinder is changed due to flow pulsating.The vortex shedding is accelerated,the cylinder vibration is enhanced,and the wall heat transfer ability is improved.The pulsation frequency increases and the vortex shedding frequency increases.The pulsation frequency has little effect on the spectrum characteristics and heat transfer characteristics.Cylinder vibration and heat transfer capacity of the cylinder increase with the increase of pulsation amplitude.The pulsation amplitude has little effect on vortex shedding frequency.With the reduced speed increasing,the vortex shedding is accelerated,the cylinder vibration is enhanced,and the heat transfer capacity of cylinder wall is improved.For the cylindrical vortex-induced vibration under the action of electromagnetic force,the electromagnetic force is mainly concentrated around the cylinder.Magnetic induction intensity and electromagnetic force decays exponentially along the radius of the cylinder.The parameters of the electromagnetic force are enhanced,the vortex shedding speed is accelerated,and the vibration of the cylinder enhances the heat transfer ability of the wall surface.The vortex shedding speed is accelerated,the vibration of the cylinder is enhanced,the heat transfer capacity of the wall is improved as the electromagnetic force action parameter is increased.When the electromagnetic interaction parameter is large enough,backflow occurs in the flow field.The vortex shedding is suppressed.