I would like to know the difference between the calculation methods for the two-phase heat transfer coefficient, CHEN and HEX5

The answer has already been found in the LTY post. I hope those with practical experience can explain which of these two methods is more suitable for real-world situations, whether there is a phase change or not How to choose? Let me share my personal opinion first. I believe that when performing heat transfer calculations involving phase changes, using HEX5 yields a final pressure drop that is quite close to the actual value, and it also matches fairly well with the results obtained using HTFS+. The two-phase heat transfer coefficient can be determined using one of two methods: the Modified Chen Vaporization method (newly added) or the HEX5 method. These two methods differ in the way they calculate the boiling and condensing film coefficients. The Modified Chen Vaporization method is the default method used by PRO/II, and it includes predictions for sub-cooled and film boiling. The condensation calculation methods take into account flow regimes as well as the effects of gravity versus shear forces. The HEX5 method is provided for backward compatibility. The two-phase heat transfer coefficient method is effective only when there are changes on either the shell side, the tube side, or both sides. In cases involving phase change, the Modified Chen Vaporization method and the HEX5 method will yield different heat transfer coefficients; whereas in cases without phase change, both methods will give identical heat transfer coefficients. Last edited by si508 on 2009-3-19 11:19

It happened to me when I was calculating the reboiler: the heat transfer coefficients obtained using the two methods differed greatly!