Experimental study of the heat transfer coefficient and pressure drop of R1234yf condensing flow in flattened smooth tubes

Fazelnia, Hamidreza; Sajadi, Behrang; Azarhazin, Soorena; Behabadi, Mohammadali Akhavan; Zakeralhoseini, Sajjad

doi:10.1016/j.ijrefrig.2019.06.003

Cited by 18 publications

(1 citation statement)

References 25 publications

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“…Circular tubes of 8.2 mm I.D. were progressively deformed to flattened tubes with three different inner heights (6.7, 5.2, and 3.1 mm) by Fazelnia et al [28] to examine the coefficient of heat transmission and pressure gradient during condensation flow of R1234yf. The test operation range was 95 -380 kg/m 2 s for mass flux and 0.15 -0.8 for gas quality.…”

Section: Introductionmentioning

confidence: 99%

Gas-liquid two-phase flow pressure drop in flattened tubes: an experimental and numerical study

YAQOP

2024

Journal of Thermal Engineering

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Experimental, numerical and empirical research is carried out on pressure drop features of air-water two-phase flow in horizontal flattened tubes. Circular tubes of 10.5 mm I.D. made of copper were successively flattened into inner heights of 9, 8, and 6 mm (AR=1.27, 1.5, and 2.2, respectively). The experiment operation conditions were 200, 500, and 1000 kg/m2s for mass velocity, 6, 8, 10 LPM for flow rate, and 0 to 0.005 for gas quality. Also, the pressure drop for R134a and R410A was estimated numerically using ANSYS Fluent. The simulation test condi-tions were for vapor quality of 0.1 to 0.9 and saturation temperature of 40°C, while the condi-tions for mass velocity and flowrate are taken as that of the experiment test. The experimental data were examined to see how different factors affect on the pressure gradient. According to the outcomes and as compared to the circular tube, the pressure gradient was raised up to 27%, 95%, and 218% for tubes ﬂattened with aspect ratio of 1.27, 1.5, and 2.2, respectively. More-over, the pressure drop for either air-water or refrigerant fluids is increased dramatically with increasing flow rate, but it decreases with increasing vapor quality. When compared to known circular tube correlations, a good agreement was achieved. Finally, the minimum difference between the experimental, numerical, and correlated results was less than 3% for gas quality of 0.0048 and aspect ratio of 2.2.

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Section: Introductionmentioning

confidence: 99%

Gas-liquid two-phase flow pressure drop in flattened tubes: an experimental and numerical study

YAQOP

2024

Journal of Thermal Engineering

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Essential technologies on the direct cooling thermal management system for electric vehicles

Yang

Zhou

et al. 2021

Intl J of Energy Research

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As the increasing concern of degradation or thermal runaway of lithium-ion batteries, direct cooling system on electric vehicles draws much attention and has been broadly researched. Although satisfactory energy efficiency and thermal performance can be achieved according to current appliances, in-depth discussion of system design and modeling is still necessary for providing mature applications. Herein, a comprehensive review of direct cooling system is presented, and essential components on the overall design are introduced as 4C chain (construction of the system, component modeling, cooling plate design, and coolant selection). Construction, coolant, cooling plate, and component modeling are presented independently for discussing the research progress, where detailed information is provided contributing to the selection of essential components. Moreover, the typical applications on electric vehicles of direct cooling are also investigated, and more productions are under research. Apart from system designing, the environmental fitness is also considered and the defects are summarized for system optimization.Considering to achieve future innovative application, digital twin model-based method is delivered for providing the guidance of prospective direct cooling system design, and the method enhances the potential to achieve better thermal management based on digital technologies and cloud-control platform. Based on the innovative development of cloud-controlling platform design and electronic and electrical architecture, the cloud battery controlling provides the chances for online elaborate model-based operation and precise model-based controlling strategy for novel direct cooling system. Novelty StatementA comprehensive review on the general construction of system is presented, and essential components of direct cooling system are also summarized for optimizing the system efficiency. The article highlights the research profile of

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Experimental performance of moderately high temperature heat pump with working fluid R1234ze(Z)

Zhang

2020

J Therm Anal Calorim

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Experimental study of the heat transfer coefficient and pressure drop of R1234yf condensing flow in flattened smooth tubes

Cited by 18 publications

References 25 publications

Gas-liquid two-phase flow pressure drop in flattened tubes: an experimental and numerical study

Gas-liquid two-phase flow pressure drop in flattened tubes: an experimental and numerical study

Essential technologies on the direct cooling thermal management system for electric vehicles

Experimental performance of moderately high temperature heat pump with working fluid R1234ze(Z)

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