Wave characteristics of a laminar-wavy R1233zd(E) refrigerant film flowing down a vertical plate
S.V. Konev1,2, O.A. Volodin1, N.I. Pecherkin1, A.N. Pavlenko1
1Kutateladze Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences (SB RAS), Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: falling liquid film, R1233zd(E), laminar-wavy flow, large three-dimensional waves, phase velocity
Abstract
This paper presents the results of an experimental study on the wave characteristics of an R1233zd(E) refrigerant film flowing down a vertical flat surface. The experiments were conducted under saturation conditions at a temperature of 26.7°C and an absolute pressure of approximately 1.4 bar. The film Reynolds numbers investigated-Re_f = 520, 1040, and 1560-correspond to the laminar-wavy flow regime. High-speed video recording was used to determine the length, phase velocity, and passage frequency of large three-dimensional waves. It is shown that as the liquid flow rate increases, the length of the large waves decreases, whereas their phase velocity and passage frequency increase. The measured phase velocities are compared with experimental data for a liquid nitrogen film and with calculated estimates based on the Kholpanov-Shkadov approximation and the correlation by Nosoko et al. It is demonstrated that the Kholpanov-Shkadov relationship significantly overestimates the phase velocity of large waves, while the correlation by Nosoko et al. better captures the order of magnitude but yields an underestimate.
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