Kuczynski, WaldemarBohdal, TadeuszMeyer, Josua P.Denis, Aleksander2019-08-302019-10Kuczynski, W., Bohdal, T., Meyer, J.P. et al. 2019, 'A regressive model for dynamic instabilities during the condensation of R404A and R507 refrigerants', International Journal of Heat and Mass Transfer, vol. 141, pp. 1025-1035.0017-9310 (print)1879-2189 (online)10.1016/j.ijheatmasstransfer.2019.06.095http://hdl.handle.net/2263/71246This paper presents the results of experimental research and mathematical modelling on the influence of dynamic instabilities on the condensation phase change of R507 refrigerant in tubular mini-channels. This agent is currently being utilised as a temporary substitute for R404A, with R448A intended as the target substitute. In addition to the results, this paper contains a dimensional analysis procedure based on the Π-Buckingham theorem that has allowed for the development of a regressive model for the velocities of the dynamic instabilities. The experimental part of this paper was conducted using tubular mini-channels with internal diameters of 1.44, 2.3, and 3.3 mm.en© 2019 Elsevier Ltd. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in International Journal of Heat and Mass Transfer. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in International Journal of Heat and Mass Transfer, vol. 141, pp. 1025-1035, 2019. doi : 10.1016/j.ijheatmasstransfer.2019.06.095.Condensation refrigerantsMini-channelsInstabilityRegression functionEngineering, built environment and information technology articles SDG-04SDG-04: Quality educationEngineering, built environment and information technology articles SDG-07SDG-07: Affordable and clean energyEngineering, built environment and information technology articles SDG-09SDG-09: Industry, innovation and infrastructurePostprint Article