Characterization of pressure-wave propagation during the condensation of R404A and R134a refrigerants in pipe mini-channels that undergo periodic hydrodynamic disturbances

In the present paper, an attempt was undertaken to model the propagation of a pressure wave triggered by periodic hydrodynamic instabilities in the condensation of the R404A and R134a refrigerants in pipe mini-channels. A homogenous transient two-fluid model was used based on balance equations. The model presents the complexity of multi-phase flows. The heat exchange between the phases in the condensation process was calculated using the one-dimensional form of Fourier’s equation. The dependence which defines the interfacial the drag forces for the flow in mini-channels was also taken into consideration. The results of the numerical calculations were verified with experimental investigations and satisfactory compliance was obtained.

► Studied the pressure wave propagation velocity during condensation of refrigerants R134a and R404A. ► Condensation process occurred in minichannels. ► In the calculations used two-phase flow model. ► Having regard to relevant flow regime obtained satisfactory agreement with experimental results of computational.