Numerical Simulation And Experimental Study On Bottom Blowing And Backward Extrusion Of Tubes Filled With Aluminum Foam

Closed-cell aluminum foam materials have the advantages of light weight,high specific stiffness,damping vibration absorption and impact energy absorption,but their stiffness is low and they can not be used independently as structural materials.The use of a single aluminum foam metal with traditional dense metals,such as aluminum alloys,steels,etc,as a structural member using certain physical or chemical means,is lightweight,energy absorbing,high in stiffness,impact resistant,and vibration resistant.With such advantages,foam metal materials have been widely used in automobiles,aerospace,transportation and other fields.At present,most of the preparation processes of foamed metal composite structures can not achieve continuous production,and for some large-sized complex structural parts,the current methods can not guarantee dimensional specifications and core porosity.In this paper,based on the traditional injection molding continuous casting process,the fusion bottom-argon blowing technology and the confluence mold design concept,a reliance on the liquid-level pressure difference to achieve the continuous production of foam metal filled with tube blowing foam and coating liquid anti-condensation Extrusion compound forming process provides a new idea and method for the continuous production of foamed aluminum sandwich tube.In order to explore the law of bubble group flow in the bottom blowing process,a bottom blowing air water model experimental platform was established.The effects of blowing flow rate,solution viscosity,and confluence mold on the rise of bubble groups were studied.It was found that when the air flow was moderate,the viscosity of the solution was increased to make the diameter of the air bubble more finely distributed and distributed evenly.Installation of the confluence mold could significantly improve the periodic fluctuation of the air bubble group and achieve the effect of converging air bubbles.In order to study the temperature field distribution during the drawing process,the thermal conductivity coefficient of foam aluminum with different cell structure was obtained by numerical simulation.The results were used to simulate the temperature field of the drawing process.The influence of different factors such as casting speed,porosity,and water-cooled heat transfer coefficient on the temperature field distribution in the drawing process was analyzed.It was found that the aluminum foam porosity had the highest matching of operating parameters,and the casting speed mainly determined whether continuous production could be achieved.In order to verify the feasibility of the proposed process,the main part of the foaming experimental device was independently designed,and the foaming experiment was designed based on the results of physical and numerical simulations.A product with the appearance of a foamed aluminum sandwich tube was preliminarily prepared,laying the foundation for further experimental research basis.