I am writing a program that compares different heat exchangers in order to select the best one for the application. I have successfully built an 11×9 array for the overall heat transfer coefficient (U), but now I am trying to build another 11×9 matrix for the log mean temperature difference (delTlm), and I am getting errors or answers that don't make sense. For example, when I did get an output for the delTlm matrix, every row had all values as the same. Here is the code that I have so far.
A = [2.4; 4.3; 7.4; 4.3; 7.4; 9.1; 2.4; 4.3; 7.4;].*0.0929; %m^2
%From problem 1, the exit temperature curves significantly flatten out
%after an NTU of 3 (returns diminish quickly). I will run the program from
%2.5 NTU to 3.5 NTU
NTU = (2.5:0.1:3.5).';for i = 1:length(NTU) %Calculating the effectiveness using the HE_effectiveness program
eff(i) = effectiveness(NTU(i), c, 'One Shell Pass'); %Finding the actual heat transfer from Qmax and the effectiveness
Q = (eff.*Qmax); %kW
%Finding the overall transfer coefficient
U = (NTU.*Cmin)./A.'; %kW/m^2*deg C
%Finding the log mean temperature difference
deltaTlm = Q./U.*A.' end
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