| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1999: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1998: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
The main results of the present study are as follows :
(1) Fundamental equation set governing three-dimensional slip casting process is proposed by extending modern filtration theory to generalized coordinate system. It consists of a basic flow rate euation, which contains the liquid velocity q and the solid migration rate r, and the continuity equations relating the divergence of vectors q and r to porosity variation with time, and a relationship between liquid pressure p_L and solid compressive pressure p_S Assuming that the direction of q and r coincide with -∇p_L=∇p_S and with the aids of compression permeability (CP)-characteristics, two partial differential equations are finally reduced. These equations were discretized with a Galerkin finite element method in space and with a finite difference method in time, and resultant matrix equations were solved using the Gauss elimination method at each time increment. Cake surface and liquid front were computed considering the effect of principal curvatures. The numerical results of slip castings in a cylindrical plaster mold showed that the proposed method enables the prediction of not only three dimensional cake growth but also time evolution of various internal conditions, such as porosity, pressure and flow rates, and further the effect of slurry concentration.
(2) A simple predictive method to determine compression permeability (CP)-characteristics are proposed, using the filtrate volume V vs. the time θ relation in the initial stage of a single constant pressure filtration run with a relatively large filter medium resistance Rm. Ten parameters, for specifing the CP- and Rm-characteristics, are searched so as to minimize the deviation of computed (V vs.θ) relation from observed one using modern filtration theory and Simplex method. Application to a Kaolin slurry system showed that the proposed method enables the rapid determination of CP- characteristics with high accuracy.
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