Spatial Inhomogeneities of Electrically Exploding Aluminum Wires in Argon Gas and Its Suppression Methods
Electrically exploding wires(EEW)for nanoparticle preparation has advantages of being low cost,high effi-ciency,providing high purity,and allowing for controllable size distribution.However,spatial homogeneities in the EEW diffusion stage is a critical influence factor of the quality of nanoparticles.In this paper,an experimental system was de-signed and constructed to investigate EEW,and the ultrafast optical diagnoses,including laser imaging,multi-frame photography,and emission spectrum analysis,could be realized.Various spatial inhomogeneities,including coronal plas-ma,spindle structures,zipper-like structures,stratification structures,local hot spots,gaps,and residual cores,were observed.The causes of these inhomogeneities were summarized as follows:atmospheric discharge,radial inhomogene-ous vaporization,thermal instability,and magnetohydrodynamic instability.A quantification method and the criteria of spatial homogeneity were established based on photographs.The effects of ambient pressure and current parameter on re-sistive stage and energy deposition were obtained.Moreover,the suppression methods of spatial inhomogeneities were proposed,including increasing ambient pressure and current rise rate.Ultimately,the parameter selection method for ho-mogeneous EEW was determined.
万方数据
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