Page 549 - Design and Operation of Heat Exchangers and their Networks

532 Appendix

f_D_t = 0.3164 / Re_t ^ 0.25;
% Blasius equation for Darcy friction factor
G_t = m_t / (N_t_p ∗ pi ∗ d_i ^ 2 / 4);
delta_p_t = N_p ∗ G_t ^ 2 / 2 / rho_t ∗ ((1 - sigma ^ 2 + K_c) ...
+ f_D_t ∗ L / d_i - CK_e); % tubeside total pressure drop, Pa

% calculation of shellside pressure drop

% pressure drop in the window area, Pa
G_w = m_s / sqrt(A_sc ∗ A_sw);
% mass velocity in the window section, kg/m2s
dh_w = 4 ∗ A_sw / (N_tw ∗ pi ∗ d_o + d_s ∗ theta_ds / 2);
if (Re_sd > 100)
delta_p_w_id = (1 + 0.3 ∗ N_rw) ∗ G_w ^ 2 / rho_s;
else
delta_p_w_id = 26 ∗ G_w ∗ mu_s / rho_s ...
∗ (N_rw / (s_t - d_o) + l_bc / dh_w ^ 2) + G_w ^ 2/
rho_s;
end
delta_p_w = N_b ∗ delta_p_w_id ∗ zeta_l;

% pressure drops in the crossflow section, Pa
if (s_l >= s_l_min)
N_rc_ = N_rc;
else
N_rc_ = N_rc - 1;
end
delta_p_b_id = N_rc_ ∗ (mu_s / d_o) ^ 2 / rho_s ∗ Hg;
delta_p_c = (N_b - 1) ∗ delta_p_b_id ∗ zeta_b ∗ zeta_l;

% pressure drops in the shellside inlet and outlet sections, Pa
delta_p_io = 2 ∗ delta_p_b_id ∗ (1 + N_rw / N_rc) ∗ zeta_b ...
∗ zeta_s;
% total shellside pressure drop, Pa
delta_p_s = delta_p_c + delta_p_w + delta_p_io;
if (abs(dt_max) < 1E-6)
break;
end
end