Page 554 - Design and Operation of Heat Exchangers and their Networks

Appendix 537

function f = opt_plate_fin_heat_exchanger(x, C_RF, scale, nvars, file)
persistent n0 f0
if isempty(n0)
n0 = 1;
f0 = 1E100;
end
f_C_RF = plate_fin_heat_exchanger(x, C_RF, scale, nvars, file, 0);
f = plate_fin_heat_exchanger(x, 1, scale, nvars, file, 0);

if (f < f0 && f_C_RF < f0)
if (f_C_RF > f )
f0 = f_C_RF;
plate_fin_heat_exchanger(x, C_RF, scale, nvars, file, 1);
else
f0 = f;
plate_fin_heat_exchanger(x, 1, scale, nvars, file, 1);
end
end
end

function f = plate_fin_heat_exchanger(x, C_RF, scale, nvars, file, n_output)
s_ff_min = 0.0001; % minimal spacing in the offset strip fins, m

% x = [N_fl, L_h, L_c, h_f_h, h_f_c, delta_f_h, delta_f_c, l_s_h,
% l_s_c, FPM_h, FPM_c]
N_fl_h = round(x(1) ∗ scale(1), 0); % number of fin layer apirss
L_h = x(2) ∗ scale(2) ∗ sqrt(C_RF);
% exchanger length in hot fluid flow direction, m
L_c = x(3) ∗ scale(3) ∗ sqrt(C_RF);
% exchanger length in cold fluid flow direction, m
h_f_h = x(4) ∗ scale(4); % fin height, m
h_f_c = x(5) ∗ scale(5); % fin height, m
delta_f_h = x(6) ∗ scale(6); % fin thickness, m
delta_f_c = x(7) ∗ scale(7); % fin thickness, m
l_s_h = x(8) ∗ scale(8); % fin strip length, m
l_s_c = x(9) ∗ scale(9); % fin strip length, m
FPM_h = x(10) ∗ scale(10); % number of fins per meter, 1/m
FPM_c = x(11) ∗ scale(11); % number of fins per meter, 1/m

m_h = 0.8962; % hot fluid mass flow rate, kg/s
m_c = 0.8296; % cold fluid mass flow rate, kg/s