222
Forward direction: z = zo
j = nc
energy: (A-7)
S2*Fo*(I+KC1) n 1
Tj,n+1 = 1 + 2*Fo*(1-KCl) Tj-1,-1 + 1 + 2*Fo*(1-KCl) TJn
dt*hfg,j
+ Csj( + 2*Fo*(1-KC1)) E,n
water: (A-8)
S1 2*FL
0j,w+1 (1 + 2*FL) Jn + (1 + 2*FL) j-l,n+l
dt
w,(1 + 2*FL) E
vapor: (A-9)
Ej,n -- [(1 + 2*Fv)pj,n+ Pvj,n 2*Fv*pvj.-,n1]
Similarly, moving in the backward direction, the derivatives
containing the properties at the node j+1 are evaluated at time step
n+1, while the others are evaluated at the current time step. The
following are the expressions for the constants KC1 and KC2 as
evaluated in the backward direction.
Pw,jCpw,jDL,j cpv,jDv,j
Pw,jCpw,jDL,j
KC2 = 2 Aj (j+l,n+l 9j,n+1) Pvj,n+1)
cpv,jD,j
+ 2 Aj (Pvj+l,n+l Pvj,l)