Spreading with Basal Solidification
by
Michael Bunk
Institute of Applied Thermo- and Fluiddynamics, Forschungszentrum Karlsruhe (GERMANY)
Coauthors: Peter Ehrhard (Institute of Applied Thermo- and Fluiddynamics, Forschungszentrum Karlsruhe GERMANY)

Spreading of melts under the influence of solidification has a wide range of applications in geology and engineering. For example the spreading of a corium melt after a severe core melt down accident can lead to critical conditions for the coolability and the subsequent long-term removal of decay heat.

We present an analytically based scheme to investigate the influence of basal solidification onto a spreading flow for liquid melts with low thermal conductivity.

We investigate the plane spreading problem over a horizontal isothermal plate in cartesian coordinates. Based on an underlying lubrication theory we derive an approximation for the velocity and temperature fields and, thus, for the solid/liquid-interface. Effects due to capillarity or liberation of latent heat are negligible. Solidification occurs at a defined temperature, no mushy regime is presumed. For the temperature field we use a quasi-steady approximation. Furthermore, we assume both thermal conductivity and density to be constant and equal in the liquid and solid phases. Solutions are found based on similarity transformations or numerical schemes using the method of lines.

The influence of solidification on the spreading flow is discussed in terms of the spreading length history which depends on various parameters, as e.g. inflow rate and solidification temperature.

Date received: March 27, 1999

Copyright © 1999 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caco-26.