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Generalized Fluid Flow Model for Ceramic Tape Casting
Author(s) -
Pitchumani Rangarajan,
Karbhari Vistasp M.
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08691.x
Subject(s) - slurry , materials science , rheology , mechanics , ceramic , thixotropy , flow (mathematics) , composite material , physics
The fluid mechanics associated with the flow of a ceramic slurry during the tape casting process is analyzed in this paper. The rheology of the slurry is described in generalized terms using the Ostwald‐de Waele power‐law equation, T = m|γ|′, where the yield constant, m , and the shear rate exponent, n, are empirical functions of the particle loading in the slurry, the particle shape and size distributions in the slurry, and the slurry temperature. The effects of an imposed pressure gradient due to the height of the slurry in the casting head, as well as those of the drag due to the moving substrate on the slurry flow, are accounted for by modeling the slurry discharge as a generalized planar Couette flow. The model yields an analytical expression for the tape thickness as a function of various slurry and process parameters. The influence of the physical parameters of the slurry and the geometrical dimensions of the casting head on the tape thickness are examined in the context of a commonly used BaTiO, system. It is shown that the various parametric effects may be represented concisely in the form of a nondimensional design plot employing (a) a flow parameter, α, (b) a shrinkage parameter, β, and (c) the rheology exponent, n .