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Title:Effects of centrifugal and coriolis forces on chimney convection during alloy solidification
Author(s):Riahi, Daniel N.
Subject(s):Chimney Convection
Alloy Solidification
Centrifugal And Coriolis Forces
Abstract:Nonlinear natural convection in cylindrical chimneys within a mushy layer during solidification of a binary alloy is investigated under a high gravity environment where the rotation axis is inclined at an angle ϒ to the high gravity vector. These chimneys produce freckles in the final form of the solidified materials. Freckles are imperfections that reduce the quality of the solidified materials. Asymptotic and scaling analyses are applied to weakly non-axisymmetric convection in the chimneys. Three important non-dimensional parameters are the solutal Rayleigh number R, the centrifugal acceleration parameter A and the Coriolis parameter T. It is found that, for some moderate values of the rotation rate and sin ϒ ≠ O, axial convection in the chimneys decreases rapidly with increasing A above some azimuthally dependent axial level. This level can also depend on the radii of the chimneys and on r and T. The axial convection also decreases with increasing T in certain range which depends on ϒ, T and R. The Coriolis effect is destabilizing for T outside this range of values, but it is less destabilizing for ϒ = ϒ0 > 180° as compared with those cases with inclined angle (ϒ0 - 180°).
Issue Date:1996-09
Publisher:Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report:TAM R 833
Genre:Technical Report
Rights Information:Copyright 1996 Board of Trustees of the University of Illinois
Date Available in IDEALS:2021-11-04

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  • Technical Reports - Theoretical and Applied Mechanics (TAM)
    TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.

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