Simultaneous Observation of Melt Flow and Motion of Equiaxed Crystals During Solidification Using a Dual Phase Particle Image Velocimetry Technique. Part I: Stage Characterization of Melt Flow and Equiaxed Crystal Motion

Observation of flow regimes and transitions during a columnar solidification experiment

“…The amount of equiaxed crystals was negligible. This is a major difference with the previous observations done under similar experimental conditions (Kharicha et al 2013a(Kharicha et al , 2013b where intense equiaxed crystals occur and freckle formation was observed. Images were recorded every minute and from the direct visualisation (PIV) and a special image treatment we could extract the thickness of the mushy zone, the total mushy fraction and the flow velocity as function of time.…”

“…The cooling from the walls and the occurrence of solidification generate various and complex phenomena. Regardless of the superheat which was employed, each experiment followed similar flow regimes as described in the previous analysis of Kharicha et al (Kharicha et al 2013a(Kharicha et al , 2013b, where however massive equiaxed crystals were present. Only the time when a regime changes into the next depends on the superheat.…”

Modeling of coupled motion and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification

“…It was observed that the crystals settled down during solidification and gradually formed a sedimentation bed on the cavity floor, which was a zone of negative segregation. This phenomenon is further confirmed and characterized through more delicate experiments4041. Both present simulation and these experiments have demonstrated that the motion of crystals due to gravity is common and plays a crucial role on the formation of the macrosegregation pattern.…”

Simultaneous optical measurement of temperature and velocity fields in solidifying liquids

“…In the past, similar layering phenomena of doublediffusive convection were reported for Hele-Shaw cells (Nishimura et al 1998). For various configurations with cooled sidewalls, layering was reported in the form of a stratified quiescent layer above a strongly convecting layer , layered convection cells (Skudarnov et al 2002) or as a so-called meandering flow regime (Kharicha et al 2013).…”

“…More recently, these studies have been extended to measure the velocity field of the melt via particle image velocimetry (PIV) (Wang et al 1999;Skudarnov et al 2002;Ghenai et al 2003). Moreover, PIV has been employed for the simultaneous analysis of clusters of equiaxed crystals by Kharicha et al (2013). Although these works have achieved a partial understanding with regard to velocity fields and solid fraction, they are still far from a comprehensive understanding of this complicated phenomenon.…”