Evaporation heat transfer and pressure drop characteristics of R-600a in horizontal smooth and helically dimpled tubes

Shafaee, M, Mashouf, H, Sarmadian, A and Mohseni, S G (2016) Evaporation heat transfer and pressure drop characteristics of R-600a in horizontal smooth and helically dimpled tubes. Applied Thermal Engineering, 107. pp. 28-36. ISSN 1359-4311

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Abstract

An experimental investigation was performed to evaluate the heat transfer and pressure drop characteristics of the hydrocarbon refrigerant R-600a during flow boiling inside a horizontal smooth tube with an inside diameter of 8.25 mm and a newly developed dimpled tube. The inner surface of the helically dimpled tube is enhanced by a newly modified pattern consists of both shallow and deep protrusions. The experimental tests were carried out varying: the refrigerant mass fluxes within the range of 155–470 kg/m2 s; the vapor qualities up to 0.8; the constant heat flux of 15.8 and saturation temperature of 56.5 °C. Observations clearly indicate that the heat transfer performance is improved as tube’s inner surface enhanced by this new pattern of protrusions. The experimental results show that the heat transfer coefficients of the dimpled tube are 1.29–2 times larger than a smooth tube with a pressure drop just ranging between 7% and 103% larger than the smooth tube. The highest enhancement in the heat transfer coefficient occurs at vapor quality of 0.2 and mass flow rate of 155 kg/m2 s. On the other hand, the maximum increase of pressure drop takes place at vapor quality of 0.8 and mass flow rate of 305 kg/m2 s.

Item Type: Article
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Research Centres and Groups: Dynamics, Control and Vehicle Research Group
The Sussex Energy Group
Thermo-Fluid Mechanics Research Centre
Subjects: Q Science > QC Physics > QC0120 Descriptive and experimental mechanics
Q Science > QC Physics > QC0251 Heat
Q Science > QC Physics > QC0251 Heat > QC0310.15 Thermodynamics
T Technology > TA Engineering (General). Civil engineering (General) > TA0349 Mechanics of engineering. Applied mechanics
T Technology > TA Engineering (General). Civil engineering (General) > TA0349 Mechanics of engineering. Applied mechanics > TA0357 Applied fluid mechanics
Depositing User: Alireza Sarmadian
Date Deposited: 02 Oct 2018 10:46
Last Modified: 02 Jul 2019 14:20
URI: http://sro.sussex.ac.uk/id/eprint/79168

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