Metallurgical and Materials Transactions B

, Volume 33, Issue 4, pp 605–612

Rayleigh-benard convection during solidification of an eutectic solution cooled from the top

Authors

  • P. Kumar
    • the Department of Mechanical EngineeringIndian Institute of Science
  • S. Chakraborty
    • the Department of Mechanical EngineeringIndian Institute of Science
  • K. Srinivasan
    • the Department of Mechanical EngineeringIndian Institute of Science
  • P. Dutta
    • the Department of Mechanical EngineeringIndian Institute of Science
Article

DOI: 10.1007/s11663-002-0040-3

Cite this article as:
Kumar, P., Chakraborty, S., Srinivasan, K. et al. Metall and Materi Trans B (2002) 33: 605. doi:10.1007/s11663-002-0040-3

Abstract

The interaction between laminar Rayleigh-Benard convection and directional solidification is studied for the case of an eutectic solution kept in a rectangular cavity cooled from the top. Experiments and numerical simulations are carried out using an NH4Cl-H2O solution as the model fluid. The flow is visualized using a sheet of laser light scattered by neutrally buoyant, hollow-glass spheres seeded in the fluid. The numerical modeling is performed using a pressure-based finite-volume method according to the SIMPLER algorithm. The present configuration enables us to visualize flow vortices in the presence of a continuously evolving solid/liquid interface. Clear visualization of the Rayleigh-Benard convective cells and their interaction with the solidification front are obtained. It is observed that the convective cells are characterized by zones of up-flow and down-flow, resulting in the development of a nonplanar interface. Because of the continuous advancement of the solid/liquid interface, the effective liquid height of the cavity keeps decreasing. Once the height of the fluid layer falls below a critical value, the convective cells become weaker and eventually die out, leading to the growth of a planar solidification front. Results of flow visualization and temperature measurement are compared with those from the numerical simulation, and a good agreement is found.

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 2002