A review on experimental investigations of refrigerant/oil mixture flow boiling in horizontal channels

Chu, Woei Chyn; Yan, Gang; Zhang, Hao; Zhao, Fufeng; Wang, Qingxian; Wang, Qiuwang

doi:10.1016/j.applthermaleng.2021.117270

Cited by 18 publications

(4 citation statements)

References 130 publications

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“…Due to a certain amount of lubricating oil escaping the compressor through the discharge line and circulating within the refrigeration system components (known as the oil circulation ratio, OCR), the interfacial tension of such mixtures significantly influences the prevailing flow patterns in convective phase-change heat transfer of refrigerant-oil mixtures. This influence extends to parameters such as bubble size, liquid entrainment, film thickness, and film dryout, all of which directly impact the heat transfer coefficient [4,5].…”

Section: Introductionmentioning

confidence: 97%

Experimental Determination of Gas-Liquid Interfacial Tension for POE ISO 10/R-134a Mixtures Using the Maximum Bubble Pressure Method

Pizarro-Recabarren,

Ferreira,

Barbosa

2024

Preprint

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This paper presents the development of an experimental apparatus designed for measuring the interfacial tension of a POE ISO 10/R-134a mixture under varying solubility conditions using the maximum bubble pressure method (MBPM). The apparatus features two capillary tubes immersed in a liquid volume against which a vapor bubble expands to determine interfacial tension. Key parameters of the MBPM, including bubble formation frequency and chamber volume, were meticulously fine-tuned for accurate calibration. Calibration was performed using a water/N2 mixture within the same apparatus, and the results were validated against established literature data. The experimental setup exhibited high sensitivity to bubble formation frequency, requiring precise maintenance at a constant rate of 1.0 Hz. Notably, the two-capillary model demonstrated superior performance compared to classical constant-adjusted models. A satisfactory fit for the R-134a/POE ISO 10 system was achieved with a mixing-law coefficient of r=1/7, highlighting significant deviation from ideal mixture behavior (r=1)

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Section: Introductionmentioning

confidence: 97%

Experimental Determination of Gas-Liquid Interfacial Tension for POE ISO 10/R-134a Mixtures Using the Maximum Bubble Pressure Method

Pizarro-Recabarren,

Ferreira,

Barbosa

2024

Preprint

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“…Thus it can be seen that the intersolution capacity of lubricants and refrigerants is very important, in order to make the two better mutually soluble, the relevant scholars have developed a higher mutual solubility with ammonia synthetic lubricants, which greatly solves the problem of ammonia refrigeration system due to refrigerant and lubricant insoluble. However, due to special conditions in the evaporator, the refrigerant/oil mixture remains in the evaporator There is the phenomenon of lubricant adhesion to the pipe wall [6]. In order to improve the heat exchange efficiency on this basis, the mathematicians studied the performance of the heat exchanger and the boiling heat exchange of the pipe [7][8].…”

Section: Introductionmentioning

confidence: 99%

Low temperature simulation of ammonia refrigeration based on dissipative molecular dynamics

et al. 2023

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To solve the problem of heat resistance of the oil film in the evaporator pipeline of the ammonia refrigeration system, it is extremely important to study the interaction mechanism of the oil/ammonia system. The method of dissipative molecular dynamics is used to simulate the oil/ammonia flow state at different temperatures and concentrations, and the mechanism of its interaction was analyzed. It was also found that various parameters are greatly affected by temperature in the research process, the linear relationship of temperature on various parameters was quantitatively calculated. The oil/ammonia system were divided into emulsion and layered liquid. The oil phase (or ammonia phase) with low percentage at low temperature all exists in the form of droplets. The oil-ammonia interfacial tension first increases and then decreases with the increase of oil content. At the same temperature, the interfacial tension reached its maximum when the oil content was 70%. The oil percentage of 30% concentration was the phase inversion point. When the oil percentage was 30-70%, the oil and ammonia two phases were stratified, and the oil adhered to the surface of the pipe wall. Therefore, the heat transfer performance of the system was the worst when the oil content was 30-70%. As the temperature increased, the interaction parameter aij decreased significantly. The linear relationship between ? and 1/T was very consistent with the Flory-Huggins mean field theory. This linear equation provided a basis for subsequent related research.

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“…Results show that the mixtures provided smaller HTC than the pure fluids at low mass flux while the shear stress effect might dominate the condensation heat transfer. Chu et al [11] reviewed the two-phase flow behavior of refrigerants impacting by lubricant oil and studied the flow regimes of refrigerant/oil mixtures both in macro-scale and micro-scale flow channels.…”

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 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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A review on experimental investigations of refrigerant/oil mixture flow boiling in horizontal channels

Cited by 18 publications

References 130 publications

Experimental Determination of Gas-Liquid Interfacial Tension for POE ISO 10/R-134a Mixtures Using the Maximum Bubble Pressure Method

Experimental Determination of Gas-Liquid Interfacial Tension for POE ISO 10/R-134a Mixtures Using the Maximum Bubble Pressure Method

Low temperature simulation of ammonia refrigeration based on dissipative molecular dynamics

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

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