Page 526 - Design and Operation of Heat Exchangers and their Networks

Appendix 509

thm = th(nx1, 1);
tcm = tc(1, ny1);
end
function [th, tc, thm, tcm] = crossflow_mixed_unmixed ...
(ntuh, ntuc, nx, ny, th, tc, A, T, D)
nx1 = nx + 1;
ny1 = ny + 1;
dx = ntuh / nx;
dy = ntuc / ny;
cc1 = (1 - dy / 2) / (1 + dy / 2);
cc2 =-dy /2/(1+dy /2);

for j=2:1:ny1
tc(1, j) = cc1 ∗ tc(1, j - 1) - cc2 ∗ (th(1, j) + th(1, j - 1));
end

for i=2:1:nx1
A(:, :) = 0;
% (1 + dx/2)∗tmh(i)-dx/4/ny∗tuc(i,2
A(1, 1) =1+dx / 2;
s=dx/2/ ny;
A(1, ny1) =-s/2;
D(1) = (1 - dx / 2) ∗ th(i - 1, 1) +s/2 ∗ (tc(i, 1) ...
+ tc(i - 1, 1) + tc(i - 1, ny1));
for j =2:1:ny
A(1, j) = - s;
D(1) = D(1) + s ∗ tc(i - 1, j);
end
for j =2:1:ny1
A(j, 1) = - dy;
A(j, j) =1+dy/ 2;
if (j == 2)
D(j) = (1 - dy / 2) ∗ tc(i, 1);
else
A(j, j - 1) = dy /2-1;
D(j) = 0;
end
end
T=A\D;