Comparison of maps of boiling modes with data from an experiment on the study of the hydrodynamics of a refrigerating agent

The existing maps of the flow modes of a two-phase stream boiling in a horizontal pipe are considered, the analysis of the existing maps of modes is carried out, their main advantages and disadvantages are noted. The results of experimental studies of the flow modes of two-phase refrigerant flows in horizontal pipes with an internal diameter of 13 mm are presented. A diagram of the auxiliary and experimental contour of a stand for determining the flow pattern is presented, on which more than 100 measurements were carried out, 40 of which were plotted on a generalized mode map. Flow modes for mass velocities in the range from 50 to 400 kg/(m2·s), saturation pressure from 0.064 to 0.681 MPa and heat flux density from 1 to 15 kW/m2 are obtained, all basic flow modes (stratified, wave, shell and ring) are obtained. The experimental results were compared with the maps proposed by the authors L. Wojtan, A. Cioncolini, L. Garbai, R. Santa, and a generalized mode map was obtained. The disadvantages of the obtained flow mode map are noted. The obtained map was compared with experimental data, and the mode map that best corresponds to the experimental results was selected. In order to obtain a unified mode map that can be used in the field of refrigeration technology, the boundary of the transition of layered and wave flow modes was constructed in terms of similarity criteria: the Lockhart – Martinelli parameter and the dimensionless velocity.