Method of Calculation for Grain Intermittent Drying
1975 Volume 37 Issue 2 Pages 209-216
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1975 Volume 37 Issue 2 Pages 209-216
In this paper the authors presented an effective method of calculation for grain intermittent drying, of which no theoretical analysis had been made. The calculation method is besed on the Sphere Drying Model, with computation of the moisture content of a unit sphere being dried intermittently.
Summary of the calculation procedure is as follows;
1. Defintion of non-dimensional time X
X=Kt (Sphere Model) or=Kt+X0 (Modified Sphere Model)
2. Single Scage Intermittent Drying
2-1. 1st Drying Period
Average moisture moistent M(X1) is calculated by eq. (21) using function Φ(X). Moisture content distribution C(X1, r) is obtained from eq. (19) using function Φ(X, r).
2-2. Intermission Period
Moisture conted distribution Ci(X2, r) is obtained from eq. (27) using function Φi(X1, X2, r).
2-3. 2nd Drying period
Average moisture content M2(X3) is calculated by eq. (37) using function Φ(X1, X2, X3), and moisture content distribution C2(X3, r) is by eq. (34) using Φ2(X1, X2, X3, r).
3. Multi-stage Intermittent Drying
‹proc. 0› (initial set): f(r)=M0
‹proc. D› (drying period): Average moisture content M(X) is calculated by eq. (8) and moisture content distribution C(X, r), by eq. (5). At the end of this procedure, make f(r)=C(Xdl, r).
‹proc. I› (intermission period): Ci(X, r) is calculated by eq. (5), and at the end of this procedure, make f(r)=C(Xil, r).
Average moisture contents and moisture content distributions of each drying period are obtained if computations are repeated as;
‹Proc. 0›→‹proc. D›→‹proc. I›→…‹proc. I›→‹proc. D›
The author also showed quite good agreement between the drying experiments and computations (see Fig. 7 and Tab. 1).
