Investigations on the effects of heater surface characteristics on the bubble waiting period during nucleate boiling at low subcooling

Sarker, Debasish; Ding, Wei; Franz, Ronald; Varlamova, Olga; Kováts, Péter; Zähringer, Katharina; Hampel, Uwe

doi:10.1016/j.expthermflusci.2018.09.021

“… [43–44] As a consequence, the wetting area becomes smaller than the spreading radius (Figure 4m‐II). The droplet performs a partial wetting state with turbulent motion, which increases conductive thermal resistance, suggesting the manifestation of the transition boiling state at 110 °C [45–46] . Thereby, the evaporation process slows down by further increasing temperature from 90 to 110 °C.…”

Section: Resultsmentioning

confidence: 99%

“…The droplet performs a partial wetting state with turbulent motion, which increases conductive thermal resistance, suggesting the manifestation of the transition boiling state at 110 °C. [45][46] Thereby, the evaporation process slows down by further increasing temperature from 90 to 110 °C. Consequently, the limited evaporation capacity of the droplet endows the nanosheets with more possibilities to arrange in the relatively stable AB stacking mode during the drop coating process.…”

Section: Methodsmentioning

confidence: 99%

Tuning the Stacking Modes of Ultrathin Two‐Dimensional Metal–Organic Framework Nanosheet Membranes for Highly Efficient Hydrogen Separation

Song,

Wang,

Zhao

et al. 2023

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Two‐dimensional (2D) metal‐organic framework (MOF) membranes are considered potential gas separation membranes of the next generation due to their structural diversity and geometrical functionality. However, achieving a rational structure design for a 2D MOF membrane and understanding the impact of MOF nanosheet stacking modes on membrane separation performance remain challenging tasks. Here, we report a novel kind of 2D MOF membrane based on [Cu2Br(IN)2]n (IN = isonicotinato) nanosheets and propose that synergetic stacking modes of nanosheets have a significant influence on gas separation performance. The stacking of the 2D MOF nanosheets is controlled by solvent droplet dynamic behaviors at different temperatures of drop coating. Our 2D MOF nanosheet membranes exhibit high gas separation performances for H2/CH4 (selectivity > 290 with H2 permeance > 520 GPU) and H2/CO2 (selectivity > 190 with H2 permeance > 590 GPU) surpassing the Robeson upper bounds, paving a potential way for eco‐friendly H2 separation.

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“… [43–44] As a consequence, the wetting area becomes smaller than the spreading radius (Figure 4m‐II). The droplet performs a partial wetting state with turbulent motion, which increases conductive thermal resistance, suggesting the manifestation of the transition boiling state at 110 °C [45–46] . Thereby, the evaporation process slows down by further increasing temperature from 90 to 110 °C.…”

Section: Resultsmentioning

confidence: 99%

Tuning the Stacking Modes of Ultrathin Two‐Dimensional Metal–Organic Framework Nanosheet Membranes for Highly Efficient Hydrogen Separation

Song,

Wang,

Zhao

et al. 2023

Angewandte Chemie

1

0

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Two‐dimensional (2D) metal‐organic framework (MOF) membranes are considered potential gas separation membranes of the next generation due to their structural diversity and geometrical functionality. However, achieving a rational structure design for a 2D MOF membrane and understanding the impact of MOF nanosheet stacking modes on membrane separation performance remain challenging tasks. Here, we report a novel kind of 2D MOF membrane based on [Cu2Br(IN)2]n (IN = isonicotinato) nanosheets and propose that synergetic stacking modes of nanosheets have a significant influence on gas separation performance. The stacking of the 2D MOF nanosheets is controlled by solvent droplet dynamic behaviors at different temperatures of drop coating. Our 2D MOF nanosheet membranes exhibit high gas separation performances for H2/CH4 (selectivity > 290 with H2 permeance > 520 GPU) and H2/CO2 (selectivity > 190 with H2 permeance > 590 GPU) surpassing the Robeson upper bounds, paving a potential way for eco‐friendly H2 separation.

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“…As to the bubble nucleation, researchers have regulated the parameters such as the surface structure of nanoelectrode, – wettability, – and hydrophobicity ,, to achieve a reduction in the critical bubble nucleation free energy. – The study implied that the heterogeneous surfaces with lower nucleation free energy, such as electrode gaps, were easier to nucleate for bubbles. Chen and Guo investigated different one-dimension nanostructure surfaces based on the critical nucleation free energy and found that the nanotubes with small diameter and the reaction site, such as inner wall, significantly affects the difficulty degree of bubble nucleation .…”

Section: Introductionmentioning

confidence: 99%

In Situ Investigation of Oxygen Bubble Evolution at Photoanode Surface Affected by Reaction Temperature

She

¹

,

Xu

²

,

Nie

³

et al. 2023

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A significant challenge associated with photoelectrochemical water splitting is the reduction of the anode photocurrent due to bubble adhesion. To achieve in situ observation of bubble evolution on the electrode surface, an electrochemistry system coupled with a high-speed camera was developed. The relations between photocurrent curves and bubble morphology were clarified on a fixed TiO 2 thin-film electrode at various reaction temperatures (303.15−343.15 K). The photocurrent during the nucleation waiting, growth, and detachment of bubble evolution increased approximately linearly with the reaction temperature, indicating a higher reaction rate and a reduction in the impedance that must be overcome during bubble growth. The shortened nucleation waiting period was illustrated via a homogeneous nucleation model. The study found that the required concentration of dissolved gas for bubble nucleation decreased with an increasing reaction temperature. The bubble oscillations (∼25 Hz) under high reaction temperatures promoted the bubble mass transfer from the perspective of gas evolution efficiency. Besides, a force balance model was established based on the experimental data of bubbles. Because of the decrease of solutal Marangoni force with the increase of reaction temperature, the bubble growth periods were shortened, along with the relatively large bubble detachment diameter, thereby efficiently accelerating bubble removal from the electrode surface.

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Investigations on the effects of heater surface characteristics on the bubble waiting period during nucleate boiling at low subcooling

Cited by 15 publications

References 29 publications

Tuning the Stacking Modes of Ultrathin Two‐Dimensional Metal–Organic Framework Nanosheet Membranes for Highly Efficient Hydrogen Separation

Tuning the Stacking Modes of Ultrathin Two‐Dimensional Metal–Organic Framework Nanosheet Membranes for Highly Efficient Hydrogen Separation

Tuning the Stacking Modes of Ultrathin Two‐Dimensional Metal–Organic Framework Nanosheet Membranes for Highly Efficient Hydrogen Separation

In Situ Investigation of Oxygen Bubble Evolution at Photoanode Surface Affected by Reaction Temperature

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