Development of a correlation for pressure drop of two-phase flow inside horizontal small diameter smooth and microfin tubes

• Published in: International journal of refrigeration Vol. 119; pp. 80 - 91
• Main Authors: Khairul Bashar, M., Nakamura, Keisuke, Kariya, Keishi, Miyara, Akio
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Ltd 01.11.2020; Elsevier Science Ltd
• Subjects: Chute de pression frictionnelle; Correlation; Corrélation; Faible diamètre; Fluids; Frictional pressure drop; Micro-ailettes; Microfin; Pressure; Pressure drop; R1234yf; Refrigerants; Refrigeration; Small diameter; Temperature; Tubes; Two phase flow; Vapors; Working fluids; Écoulement diphasique; Corrélation; Correlation; Microfin; R1234yf; Two-phase flow; Small diameter; Micro-ailettes; Frictional pressure drop; Chute de pression frictionnelle; Écoulement diphasique; Faible diamètre
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2020.08.013

•Two-phase frictional pressure drop inside small diameter smooth and microfin tubes is measured experimentally.•The effects of mass velocity, vapor quality, tube diameter and refrigerant properties on the pressure drop are clarified.•A new frictional pressure drop correlational for small diameter tube is proposed. This study investigated the pressure drop of adiabatic vapor-liquid two-phase flow inside horizontal smooth and microfin tubes with 2.5 mm outside diameter. R134a and R1234yf were used as working fluid and the experiments were carried out at saturation temperatures of 20 and 30°C, mass velocities ranging from 50 to 200 kg m−2s−1 and vapor qualities ranging from 0.1 to 0.9. The effects of mass velocity, vapor quality, refrigerant properties and tube diameter on the pressure drop were analyzed. Some typical previous pressure drop correlations were used to predict the experimental data. A new two-phase pressure drop correlation for small diameter tubes was proposed based on the experimental data. The new correlation agrees with the available other researchers’ data and it can be broadly applied to the small diameter smooth and microfin tubes, wide range of mass velocity and many kinds of refrigerants.