Page 525 - Design and Operation of Heat Exchangers and their Networks

508 Appendix

function [th, tc, thm, tcm] = crossflow_mixed_mixed ...
(ntuh, ntuc, nx, ny, th, tc)
nx1 = nx + 1;
ny1 = ny + 1;
eh = (1 - exp(- ntuh)) / ntuh;
ec = (1 - exp(- ntuc)) / ntuc;
s =1-(1-eh) ∗ (1 - ec);
c1 = (1 - ec) ∗ eh / s;
c2 = eh / s;
thm = (th(1, 1) + th(1, ny1)) / 2;
for j=2: 1:ny
thm = thm + th(1, j);
end
thm = thm / ny;
tcm = (tc(1, 1) + tc(nx1, 1)) / 2;
for i=2: 1:nx
tcm = tcm + tc(i, 1);
end
tcm = tcm / nx;
for j=1: 1:ny1
th(1, j) = thm;
end
for i=2: 1:nx1
s = c1 + (1 - c1) ∗ exp(- (i - 1) / nx ∗ ntuh);
s = tcm + (thm - tcm) ∗ s;
for j=1:1:ny1
th(i, j) = s;
end
end
for i=1: 1:nx1
tc(i, 1) = tcm;
end
for j=2: 1:ny1
s=c2 ∗ (1 - exp(- (j - 1) / ny ∗ ntuc));
s = tcm + (thm - tcm) ∗ s;
for i=1:1:nx1
tc(i, j) = s;
end
end