2. Sizing

There are two different approaches to hydraulic and thermal calculation of an ECD:

• a global approach based on the use of the logarithmic mean temperature difference (LMDT) and the volume exchange coefficient. This coefficient overcomes the lack of knowledge of, or difficulty in understanding, the effective exchange surface between phases and the nature of the flow. The approach applies to both types of EDC, but we'll be looking at it as the specific method for sizing surface exchangers, whose hydraulics are particularly complex;

• a local approach based on writing the momentum and energy balances of the two fluids in a control volume built on the flow cross-section. The calculation is then extended to the entire exchanger meshed in a one-dimensional network, with possible consideration of the phenomenon of axial...