Theoretical analysis of film condensation of water vapor, R134a, R600a, and R1234yf on an isothermal vertical plane surface Su buharı, R134a, R600a ve R1234yf’nin eşsıcaklıklı düzlemsel düşey bir yüzeydeki film yoğuşmasının teorik analizi

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BİLEN K., Erdoğan İ.

Journal of the Faculty of Engineering and Architecture of Gazi University, cilt.40, sa.3, ss.1857-1874, 2025 (SCI-Expanded, Scopus, TRDizin)

Özet

In this theoretical study, laminar, wavy laminar, and turbulent film condensation of the stagnant and pure vapors of water, R134a, R600a, and R1234yf fluids on an isothermal vertical plane surface were examined separately. In this study, where film condensation was examined both hydrodynamic and thermal aspects; variation of the liquid film thickness, amount of vapor condensed per unit time per unit width, and local and average heat transfer coefficients along the vertical direction were obtained for saturation temperatures of 42, 45, 50, and 55 °C. In the study also, the effect of the corrected latent heats of vaporization, which were obtained by assuming that temperature in the liquid film changes linearly and suggested one by Rohsenow, on the above parameters was determined. Nusselt’s solution was benefited for laminar and wavy laminar film condensation, and Kutateladze’s approach was also used for wavy laminar film condensation, and Labuntsov’s approach was used for turbulent film condensation. Considering all the cases examined together, in laminar film condensation, water provided 24.08% more performance than R1234yf in terms of liquid film thickness, 147.32% less performance than R134a in terms of condensed fluid per unit time per unit width, and 88.68% more performance in terms of local heat transfer coefficient at the end of the plate and average heat transfer coefficient. Meanwhile, in wavy laminar and turbulent film condensation, water provided 76.51% and 79.23% more performance than R600a in terms of average heat transfer coefficient, respectively. Ultimately, it was observed that the corrected latent heats of vaporization did not have a significant effect on the investigated parameters.