Page 547 - Design and Operation of Heat Exchangers and their Networks

530 Appendix

% correction factors for the effects of tube-to-baffle and
% baffle-to-shell leakages (A and E streams)
J_l = 0.44 ∗ (1 - r_s) + (1 - 0.44 ∗ (1 - r_s)) ∗ exp(-2.2 ∗ r_lm);
zeta_l = exp(-1.33 ∗ (1 + r_s) ∗ r_lm ^ (0.8 - 0.15 ∗ (1 + r_s)));

% correction factors for the effects of bundle and pass partition
% bypasses (C and F streams)
Re_sd = m_s ∗ d_o / (A_sc ∗ mu_s); % shellside Reynolds number
if (Re_sd <= 100)
C_bh = 1.35;
C_bp = 4.5;
n=1/3;
n1 = 1;
else
C_bh = 1.25;
C_bp = 3.7;
n = 0.6;
n1 = 0.2;
end
if (r_ss < 0.5)
J_b = exp(- C_bh ∗ r_b ∗ (1 - (2 ∗ r_ss) ^ (1 / 3)));
zeta_b = exp(- C_bp ∗ r_b ∗ (1 - (2 ∗ r_ss) ^ (1 / 3)));
else
J_b = 1;
zeta_b = 1;
end
% correction factor for larger baffle spacing at the inlet and
% outlet sections compared to the central baffle spacing
J_s = (N_b - 1 + (l_bi / l_bc) ^ (1 - n) + (l_bo / l_bc) ...
(1 - n)) / (N_b - 1 + l_bi / l_bc + l_bo / l_bc);
^
zeta_s = (l_bc / l_bo) ^ (2 - n1) + (l_bc / l_bi) ^ (2 - n1);
% correction factor for adverse temperature gradient buildup in
% laminar flows
J_r_l = (10 / (N_rc + N_rw)) ^ 0.18;
if (Re_sd <= 20)
J_r = J_r_l;
elseif (Re_sd < 100)
J_r = J_r_l + (1 - J_r_l) ∗ (Re_sd - 20) / 80;