In the latest version, change the following values of the shell and tube side properties as mentioned below:
Shell Inlet Diameter from 1000 to 1000000
Baffle Spacing from 250 to 250000
Tubes Internal Diameter from 15 to 15000
Tubes External Diameter from 20 to 20000
Roughness from 0.05 to 50
Tube Spacing from 25 to 25000
In other words, all the parameters of the shell and tube side which have units displayed as mm have been multiplied by 1000. This is due to a recent change in the source code of DWSIM where the unit of the above-mentioned parameters is considered to be in micrometer during the calculation. While this tutorial was created, the unit system used in the source code was millimeter.
However, you might see a slight variation in the results. This is due to some minor bug fixes in the shell & tube heat exchanger code.