Effect of surface tension, gravity and turbulence on condensation patterns of R1234ze(E) in horizontal mini/macro-channels

Wen, Jian; Gu, Xin; Liu, Yuce; Wang, Simin; Li, Yanzhong

doi:10.1016/j.ijheatmasstransfer.2018.04.039

Cited by 26 publications

(8 citation statements)

References 59 publications

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“…As mentioned previously, the HTC is related to the refrigerant thermal properties and operating conditions due to the changes of surface tension, gravity, shear stress and turbulence effects, which was concluded by Wen et al [18]. In order to demonstrate the effect of mass flux and vapor quality on the two-phase flow pattern and local HTC of R32 flow condensation in the HO tube, the liquid-vapor phase distribution, phase interface and local liquid film thickness (LLFT) as well as local heat transfer coefficient (LHTC) are depicted, respectively.…”

Section: Analysis On Local Characteristicsmentioning

confidence: 74%

“…Guo et al [17] investigated the effect of tube inclination on the heat transfer of gravity-driven granular flow around tube out-wall, and they suggested the inclination angle should be between 15 • and 37.5 • for better heat transfer performance. Wen et al [18] studied the influence of surface tension, gravity and turbulence on condensation patterns of R1234ze(E) in horizontal tubes with different diameters. It is noted that the surface tension played an important role in the heat transfer by enhancing the flow convection between liquid film and wall surface while gravity effect was negligible in mini-channels.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Study on R32 Flow Condensation in Horizontally Oriented Tubes with U-Bends

et al. 2022

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In this paper, the flow condensation heat transfer characteristics of R32 in a horizontally oriented tube with a horizontal U-bend (HUB tube) and a horizontally oriented tube with a vertical U-bend (VUB tube) were numerically investigated. The volume of fluid (VOF) multiphase model with the mass transfer assumption by Lee is adopted to simulate the flow condensation behavior of R32, which are validated by well-known empirical correlations. The influence of structural parameters, mass flux and vapor quality on the heat transfer coefficient (HTC) and liquid film distribution is investigated. Meanwhile, the local liquid film thickness (LLFT) and local heat transfer coefficient (LHTC) are also depicted. The phase transition at the U-bend section is captured. Results show that the U-bend has remarkable disturbance on the flow pattern and LHTC due to the effect of centrifugal force where the LLFT is changed, inducing strong secondary flow. The LHTC is increased by a maximum of 8.47% and 11.86% in VUB tube and HUB tube, respectively, when compared to the case in a horizontally straight oriented tube at the same operating conditions.

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Section: Analysis On Local Characteristicsmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Numerical Study on R32 Flow Condensation in Horizontally Oriented Tubes with U-Bends

et al. 2022

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“…In addition, it is reported by Charnay et al 26 that an enhancement in heat transfer performance can be achieved by reducing the tube diameters. Moreover, it is reported by Wen et al 27 that the shear stress between the solid‐liquid interface plays a major role in thinning of the film thickness of the condensate, resulting in less flow resistance at the liquid‐vapor interface. This creates enough space for the vapor to move toward the condenser section and reduces the level of irreversibility that takes place due to heat transfer between evaporator and condenser section.…”

Section: Resultsmentioning

confidence: 99%

Feasibility of using multiport minichannel as thermosyphon for cooling of miniaturized electronic devices

et al. 2020

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“…A range of turbulence models has been implemented in flow condensation simulations. Shear Stress Transport (SST) model has been used by many researchers for computational condensation phase change analysis 39,57,58 . The SST k-ω is a two-equation eddy-viscosity model, which assumes the proportional relationship between Reynolds shear stress and turbulent kinetic energy in the boundary layer 59 .…”

Section: Turbulence Modelmentioning

confidence: 99%

Parametric study on hydrothermal properties of condensing flow in microtube heat exchangers using numerical and experimental approaches

Sadaghiani¹

2021

Preprint

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Microchannels have increasingly been used to miniaturize heat transfer equipment, improve energy efficiency, and minimize heat transfer fluid inventory. A fundamental understanding of condensation in microscale will yield far-reaching benefits for the different areas of industry. In this study, microtubes with inner diameters of 250, 500, 600, and 900 µm were used to investigate the effect of microtube diameter, inlet quality, and mass flux on the liquid/vapor interface near the wall boundaries in condensing flow. After validation with the experimental results, a transient numerical model (based on the volume of fluid approach) was developed to investigate the hydrothermal properties of condensing such as bubble dynamics, flow map transitions, transient interface shear force, and temperature on flow condensation performance in terms of heat transfer coefficient and pressure drop. The liquid film thickness, slug velocity, and location of transition from annular flow to slug flow inside the microtube were characterized for different microtubes, and the resultant alteration in condensation flow heat transfer and pressure drop is discussed in detail. The obtained results indicated that the interfacial characteristics of condensing flow in microtubes with hydraulic diameters lower than 500µm are majorly different from those with D>500µm.

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Effect of surface tension, gravity and turbulence on condensation patterns of R1234ze(E) in horizontal mini/macro-channels

Cited by 26 publications

References 59 publications

Numerical Study on R32 Flow Condensation in Horizontally Oriented Tubes with U-Bends

Numerical Study on R32 Flow Condensation in Horizontally Oriented Tubes with U-Bends

Feasibility of using multiport minichannel as thermosyphon for cooling of miniaturized electronic devices

Parametric study on hydrothermal properties of condensing flow in microtube heat exchangers using numerical and experimental approaches

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