On the mechanism of boiling heat transfer enhancement by surfactant addition

Wang, Jue; Li, Feng‐Chen; Li, Xiaobin

doi:10.1016/j.ijheatmasstransfer.2016.05.121

Cited by 43 publications

(7 citation statements)

References 16 publications

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“…This is due to the surface characteristics, which leads to the enhancement in wettability of surface due to the entrapment of ethanol in the porous structures . Besides, the ethanol shows higher wettability on the surface treated for 2 hours than that of 4 hours, which shows that high porosity plays an important role in affecting wettability …”

Section: Resultsmentioning

confidence: 99%

New insights for phase-change immersion cooling enhancement of solar cells under high concentration ratios

et al. 2017

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Summary To answer how surface corrosion affects the heat transfer performance of phase‐change immersion cooling solar cells, electrochemical etching was used for substrate surface treatment of simulated dense‐array solar cells in this paper. Morphology, roughness, and wettability of treated surfaces were characterized by scanning electron microscope, atomic force microscope, and spreading area, respectively. A self‐running cooling system was developed to investigate the effect of surface treatment on self‐running characteristics and heat transfer performance under different ethanol inlet temperatures and concentration ratios. The results show that the surface treated for 2 hours owns higher wettability because of the honeycomb‐like porous structure. Lower ethanol flowing velocity obtained under lower ethanol inlet temperature with treated samples. The maximum declined degree in the wall superheating of 21.1% and the maximum enhancement in the heat transfer coefficient of 33.3% are obtained for sample treated for 2 hours because of its higher wettability and porosity structure. The results show that electrochemical etching on substrate surface can improve the phase‐change immersion cooling performance of solar cells.

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Section: Resultsmentioning

confidence: 99%

New insights for phase-change immersion cooling enhancement of solar cells under high concentration ratios

et al. 2017

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“…Previous work indicated that the surfactant droplet with lower surface tension will accelerate the vaporization rate at the same surface temperature, ,,− making it easier to be lifted from the surface by the intensely formed vapor and the Leidenfrost phenomenon can occur at much lower temperatures. But some work has found that a low surface tension reduces the critical wavelength of hydrodynamic instability, − making it more difficult to form a stable liquid film between the liquid and the solid, thereby increasing the LFP temperature.…”

Section: Introductionmentioning

confidence: 99%

Enhancing Boiling Heat Transfer on a Superheated Surface by Surfactant-Laden Droplets

et al. 2022

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Boiling, one of the most common phase-change heat transfer methods, is widely used in nuclear power plants, spacecraft, integrated circuits, and other situations, where rapid and efficient heat transfer is crucial. However, boiling heat transfer is efficient only in a specific surface temperature range when a droplet impacts a superheated surface. Here, we enhance the boiling heat transfer and extend this temperature range by adding a tiny amount of surfactant. We find that surfactants can weaken the Kelvin effect of boiling bubbles, and thus reduce the onset of boiling driven temperature and significantly enhance the maximum vaporization rate of the droplet effectively. In particular, different from previous studies, we find that the surfactants at lower concentrations can increase the Leidenfrost temperature of the droplets. All the above effects jointly expand the temperature range of effective boiling heat transfer. This study sheds new light on the role of surfactants in the boiling process and offers a new medium to promote heat-transfer applications.

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“…The information gathered from the studies dealing with working fluids provides valuable insights into the critical thermo-physical properties and their changeable effects depending on operational conditions. In the light of this information, some researchers focused on decreasing surface tension of the working fluids via surfactants since it is known that surface tension is directly related to bubble dynamics and nucleation, and the fluids having lower surface tension can easily produce lots of bubbles with relatively smaller diameter [12]. In this regard, Xing et al [13] used a working fluid which is a mixture of water and cetyl trimethyl ammonium bromide (as surfactant) with different concentrations between 0.025 and 0.25%.…”

Section: Introductionmentioning

confidence: 99%

Thermal investigation and flow pattern analysis of a closed-loop pulsating heat pipe with binary mixtures

Markal

Varol

2020

J Braz. Soc. Mech. Sci. Eng.

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The present study basically examines thermal performance and relevant flow phenomena of a flat plate closed-loop pulsating heat pipe (FP-CLPHP) filled with binary mixtures. The heat pipe has eight turns, each of which consisting of asymmetrical channel pairs having cross sections as 2 mm × 2 mm and 1 mm × 2 mm (width × height). Binary mixtures are generated as mixtures of ethanol (E) and pentane (P) with different mixing ratios. Mainly, effects of volume mixing ratio (E/P = 1:1, 1:3 and 3:1), vertical (90°) and horizontal orientation (0°) and filling ratio (30% and 60%) on thermal characteristics are investigated under different heat inputs. For examination of flow dynamics, images are obtained by using a high-speed camera at 1000 fps. The results show that variation of volumetric percentage of each component significantly changes thermal performance. Increasing pentane in the mixture improves the thermal performance, such that heat pipe with mixing ratio of E/P = 1:3 can properly operate even at horizontal position. On the other hand, increasing volume of ethanol in mixture leads to collapse of the FP-CLPHP at both orientations (0° and 90°). Generally, the filling ratio of 30% shows better thermal performance. Complex bubble-liquid interactions and dynamics play critical roles on thermal characteristics. Two novel characteristic phenomena are identified for non-uniform PHPs: (1) flooding phenomenon and (2) asymmetrical rapid bubble growth phenomenon. Keywords Thermal performance • Flow visualization • Bubble dynamics • Heat pipe List of symbols A bi Bubble interface area (m 2) A app Shear force acting area (m 2) D h Hydraulic diameter (m) Q i Heat input (W) Q rh Removed heat via cooling water (W) R th Total thermal resistance (°C W −1) T Temperature (°C) Greek symbols Angle between the heat pipe and horizontal position (°) Dynamic viscosity (Pa s)

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On the mechanism of boiling heat transfer enhancement by surfactant addition

Cited by 43 publications

References 16 publications

New insights for phase-change immersion cooling enhancement of solar cells under high concentration ratios

New insights for phase-change immersion cooling enhancement of solar cells under high concentration ratios

Enhancing Boiling Heat Transfer on a Superheated Surface by Surfactant-Laden Droplets

Thermal investigation and flow pattern analysis of a closed-loop pulsating heat pipe with binary mixtures

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