Melting and Solidification of a Pure Metal on a Vertical Wall
0. Gau R. Viskanta
Fellow ASME Heat Transfer Laboratory, Scool of Mechanical Engineering, Purdue University, West Lafayette, IN 47907
citing and Solidification of a Pure Metal on a Vertical Wall
This paper reports on the role of natural convection on solid-liquid interface motion and heat transfer during melting and solidification of a pure metal {gallium) on a vertical wall. The measurements of the position of the phase-change boundary as well as of temperature distributions and temperature fluctuations were used as a qualitative indication of the natural convection flow regimes and structure in the melt during phase transformation taking place in a rectangular test cell heated or cooled from one of the vertical walls. For melting, the measured melt volume and heat transfer coefficients are correlated in terms of relevant dimensionless parameters. For solidification, the measured volume of metal solidified on the wall is compared with predictions based on a one-dimensional model.
Introduction Heat transfer in the processing of materials involving solid-liquid phase transformations (melting and solidification) is commonplace in such fields as metallurgy, crystal growth from melts and solutions, purification of materials, and solidification of metals. The associated density gradients in a gravitational field can induce natural convection flows. Convection in the liquid phase influences the process in two different ways, one of which is beneficial and the other of which can be detrimental. During melting convection increases the overall transport rate and, hence, the growth rate of the new phase, which is desirable. On the other hand, during solidification convection decreases the growth of the new phase and also seems to affect the morphology of the solid-liquid interface adversely [1, 2]. The nature of the solid is largely determined by what occurs in the vicinity of the solid-liquid interface. The heat release (absorption), density change, and other
Fellow ASME Heat Transfer Laboratory, Scool of Mechanical Engineering, Purdue University, West Lafayette, IN 47907
citing and Solidification of a Pure Metal on a Vertical Wall
This paper reports on the role of natural convection on solid-liquid interface motion and heat transfer during melting and solidification of a pure metal {gallium) on a vertical wall. The measurements of the position of the phase-change boundary as well as of temperature distributions and temperature fluctuations were used as a qualitative indication of the natural convection flow regimes and structure in the melt during phase transformation taking place in a rectangular test cell heated or cooled from one of the vertical walls. For melting, the measured melt volume and heat transfer coefficients are correlated in terms of relevant dimensionless parameters. For solidification, the measured volume of metal solidified on the wall is compared with predictions based on a one-dimensional model.
Introduction Heat transfer in the processing of materials involving solid-liquid phase transformations (melting and solidification) is commonplace in such fields as metallurgy, crystal growth from melts and solutions, purification of materials, and solidification of metals. The associated density gradients in a gravitational field can induce natural convection flows. Convection in the liquid phase influences the process in two different ways, one of which is beneficial and the other of which can be detrimental. During melting convection increases the overall transport rate and, hence, the growth rate of the new phase, which is desirable. On the other hand, during solidification convection decreases the growth of the new phase and also seems to affect the morphology of the solid-liquid interface adversely [1, 2]. The nature of the solid is largely determined by what occurs in the vicinity of the solid-liquid interface. The heat release (absorption), density change, and other
References: 1 Flemings, M., Solidification Processing, McGraw-Hill, New York, 1974.