Plotting grapf of heat exchanger
2 views (last 30 days)
Show older comments
I'm trying to plot the grapf of a heat exchanger, I already calculated the values but have struggle in plotting it.
The simple form of my code is this:
clear all
clc
c=[];
Teth_in=195; %[K]
Tgas_out=230; %[K]
ms_gas=0.342; %[kg/s]
ms_eth=0.412; %[kg/s]
cp_gas=3600;
cp_eth=2440;
dia=25*(10^-3);
for Tgas_in=230:1:290 %[K]
Q_in=ms_gas*cp_gas*(Tgas_out-Tgas_in);
Teth_out=-Q_in/(ms_eth*cp_eth)+Teth_in;
Q_out=ms_eth*cp_eth*(Teth_in-Teth_out);
%% Logarithmischer Temperaturdifferenz in Gegenstrom Wärmetauscher:
delta_T1 = Tgas_in - Teth_out; % [K]
delta_T2 = Tgas_out - Teth_in; % [K]
delta_Tm = (delta_T1 - delta_T2) / (log10(delta_T1/delta_T2)/(log10(exp(1)))); % [K]
U=450;
Lx=-Q_in/(U*pi*dia*delta_Tm);
c=[c; Lx delta_Tm Teth_out Tgas_in];
end
plot(c(:,1),c(:,3))
hold on
plot(c(:,1),c(:,4))
grid on
xlabel('Länge [m]')
ylabel('Temperatur [K]')
title('Wärmetauscher Kühlungsverlauf')
legend('Ethanol','Erdgas','location','northwest')
The grapf should be like this:
the grapf i plotted is this:
The problem is that the Lx value is being taken wrong. For example for the red curve , when Lx is 0 then the y-value should be 290, and when Lx is 75 then the y-value should be 230. At the end should get a grapf like the first grapf i added. I hope someone can help me
0 Comments
Answers (1)
Arthi Sathyamurthi
on 24 May 2021
The plot(c(:,1), c(:,3)) considers the first value of c(:,1) as x coordinate and first value of c(:,3) as the y coordinate and increments in order for both x and y coordinates. Your values in c(:,3) has the values inverted. Use the function flipud to flip the rows in the up-down direction and plot the same.
The code snippet would be
plot(c(:,1),flipud(c(:,3)))
hold on
plot(c(:,1),flipud(c(:,4)))
0 Comments
See Also
Categories
Find more on Line Plots in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!