Research On Jet Cooling Flow Field And Temperature Field Of Amorphous Zirconium Alloy Continuous Casting

As a new type of material,amorphous zirconium alloy has the advantages of high hardness,high strength,low elastic modulus and excellent corrosion resistance,and has wide application prospects.In order to realize the continuous preparation of amorphous zirconium alloy sheet,the research group independently invented a double belt type amorphous zirconium alloy continuous casting machine that uses jet cooling as a cooling method.During the cooling process of the jet,the cooling rate of the amorphous zirconium alloy needs to be ensured,and uniform cooling of the heat exchange wall surface is achieved at the same time.The jet cooling process of the amorphous zirconium alloy continuous casting machine is studied in this paper.Based on Martin et al.'s experiments,different turbulence models were used to calculate the jet cooling flow field.It was found that the SST k-? turbulence model can make a good prediction of the jet cooling flow field.Using the SST k-? turbulence model,the jet cooling heat flow coupling model of the amorphous zirconium alloy continuous casting machine was established,and the injection velocity,nozzle spacing,nozzle diameter and nozzle height were analyzed.The Nusselt number and the variation of the coefficient of Nusselt number were obtained under different parameters.With the increase of the above four factors,the Nusselt number of the wall surface is increased in different degrees,that is,the heat transfer intensity of the wall surface is enhanced,but an excessively high nozzle height will cause the attraction of the adjacent two jets,making the flow field unstable;With the increase of spray velocity and nozzle diameter,the nozzle spacing and nozzle height can reduce the coefficient of variation of the Nusselt number of the wall surface,that is,improve the uniformity of the heat transfer on the wall surface.However,if the nozzle pitch is too small,the flow field can easily be attracted.The chaos in the flow field is not conducive to cooling.For the purpose of improving the uniformity of heat exchange on the wall surface,the effect of four factors on the uniformity of heat transfer is analyzed through orthogonal tests.Its size is in order: nozzle diameter,nozzle height,jet speed,nozzle spacing,And get the best combination of parameters.The numerical simulation of the model under the optimal parameter combination shows that the coefficient of variation of the Nusselt number on the heat transfer wall surface can be reduced to 0.3056.The cooling rate of the slab at the lowest cooling rate is 13°C/s.The zirconium alloy melt completely completes the amorphous transformation within 25 s.