Experimental investigation of NH₄Cl-H₂O eutectic solution solidification for simulating crystal growth with Bridgman method

The crystal growth process with Bridgman method was simulated via NH₄Cl-H₂O solution eutectic solidification. The flow fields of NH₄Cl-H₂O solution during solidification in both rectangular cavity and cylindrical cavity were measured with particle image velocimetry (PIV). With the temperature varying, the coupling rules of fluid flow and temperature during eutectic solidification process were observed. Cooling both at sidewall and bottom, the evolution of flow field was about the same in the two kinds of cavities during the solidification process. Convection vortex occurred in the liquid region flowing downward along the vertical sidewalls, and upward in the center region. Heat transfer and latent heat release made the temperature decrease slowly. The rule between flow field and temperature during the eutectic solidification approached the crystal growth process of Bridgman method, and offered valuable data for theoretical modeling and numerical calculation.