CONDENSATION IN MINICHANNELS: EXPERIMENTAL INVESTIGATION AND NUMERICAL MODELING

This paper presents an overview of the most recent research works on condensation heat transfer inside minichannels with halogenated refrigerants. The first part is focused on the experimental results available in the scientific literature and the effect of the main parameters (channel diameter, mass velocity, vapor quality, saturation temperature, heat flux, channel orientation) on convective condensation. In particular the effect of channel shape is treated, showing that at low mass velocity some peculiar characteristics of microscale condensation can be observed. In the second part, numerical models of condensation in minichannels are presented. These models should be able to simulate the heat transfer process resolving the momentum and energy equations, without or at least with a reduced number of empirical inputs. One important feature of the numerical modeling is to provide an insight into the heat transfer mechanisms that may be difficult to get only from the experimental investigation. However, note that such numerical models, due to the heavy computational effort required, are still far from being widely applied in the heat exchanger design.