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Numerical experiments on evaporation and explosive boiling of ultra-thin liquid argon film on aluminum nanostructure substrate.

Wang W, Zhang H, Tian C, Meng X - Nanoscale Res Lett (2015)

Bottom Line: Those simulations begin with an initial configuration for the complex liquid-vapor-solid system, followed by an equilibrating system at 90 K, and conclude with two different jump temperatures, including 150 and 310 K which are far beyond the critical temperature.The space and time dependences of temperature, pressure, density number, and net evaporation rate are monitored to investigate the phase transition process on a flat surface with and without nanostructures.The simulation results reveal that the nanostructures are of great help to raise the heat transfer efficiency and that evaporation rate increases with the nanostructures' height in a certain range.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Mechanical Engineering, Xidian University, No. 2 South Taibai Road, Xi'an, Shaanxi 710071 China ; State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, No. 99 Yanxiang Road, Xi'an, Shaanxi 710054 China ; Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.

ABSTRACT
Evaporation and explosive boiling of ultra-thin liquid film are of great significant fundamental importance for both science and engineering applications. The evaporation and explosive boiling of ultra-thin liquid film absorbed on an aluminum nanostructure solid wall are investigated by means of molecular dynamics simulations. The simulated system consists of three regions: liquid argon, vapor argon, and an aluminum substrate decorated with nanostructures of different heights. Those simulations begin with an initial configuration for the complex liquid-vapor-solid system, followed by an equilibrating system at 90 K, and conclude with two different jump temperatures, including 150 and 310 K which are far beyond the critical temperature. The space and time dependences of temperature, pressure, density number, and net evaporation rate are monitored to investigate the phase transition process on a flat surface with and without nanostructures. The simulation results reveal that the nanostructures are of great help to raise the heat transfer efficiency and that evaporation rate increases with the nanostructures' height in a certain range.

No MeSH data available.


Related in: MedlinePlus

Pressure variation of argon regions for the case with a 310 K heated source.
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Fig4: Pressure variation of argon regions for the case with a 310 K heated source.

Mentions: Figure 4 indicates the evolution curves of the pressure in the liquid and vapor argon regions, which are similar to the temperature trends given in Figure 3. It can be observed from Figure 4 that during the initial equilibration period from 0.5 to 1 ns, the liquid and vapor pressure fluctuates around 0 bar. Once the explosive boiling occurs, the pressure of liquid and vapor regions increases rapidly because of rapid expansion of liquid argon in a constant simulation volume. It is also shown that the higher the nanoposts, the quicker the argon pressure reaches to equilibrium. At 6 ns, the gas pressures for surfaces 2 and 3 basically reach their steady states; nevertheless, those for surfaces 0 and 1 are far from their equilibrium states, which is the reason that not all liquid argon atoms evaporate at the end of simulation time.Figure 4


Numerical experiments on evaporation and explosive boiling of ultra-thin liquid argon film on aluminum nanostructure substrate.

Wang W, Zhang H, Tian C, Meng X - Nanoscale Res Lett (2015)

Pressure variation of argon regions for the case with a 310 K heated source.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401484&req=5

Fig4: Pressure variation of argon regions for the case with a 310 K heated source.
Mentions: Figure 4 indicates the evolution curves of the pressure in the liquid and vapor argon regions, which are similar to the temperature trends given in Figure 3. It can be observed from Figure 4 that during the initial equilibration period from 0.5 to 1 ns, the liquid and vapor pressure fluctuates around 0 bar. Once the explosive boiling occurs, the pressure of liquid and vapor regions increases rapidly because of rapid expansion of liquid argon in a constant simulation volume. It is also shown that the higher the nanoposts, the quicker the argon pressure reaches to equilibrium. At 6 ns, the gas pressures for surfaces 2 and 3 basically reach their steady states; nevertheless, those for surfaces 0 and 1 are far from their equilibrium states, which is the reason that not all liquid argon atoms evaporate at the end of simulation time.Figure 4

Bottom Line: Those simulations begin with an initial configuration for the complex liquid-vapor-solid system, followed by an equilibrating system at 90 K, and conclude with two different jump temperatures, including 150 and 310 K which are far beyond the critical temperature.The space and time dependences of temperature, pressure, density number, and net evaporation rate are monitored to investigate the phase transition process on a flat surface with and without nanostructures.The simulation results reveal that the nanostructures are of great help to raise the heat transfer efficiency and that evaporation rate increases with the nanostructures' height in a certain range.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical and Mechanical Engineering, Xidian University, No. 2 South Taibai Road, Xi'an, Shaanxi 710071 China ; State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, No. 99 Yanxiang Road, Xi'an, Shaanxi 710054 China ; Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.

ABSTRACT
Evaporation and explosive boiling of ultra-thin liquid film are of great significant fundamental importance for both science and engineering applications. The evaporation and explosive boiling of ultra-thin liquid film absorbed on an aluminum nanostructure solid wall are investigated by means of molecular dynamics simulations. The simulated system consists of three regions: liquid argon, vapor argon, and an aluminum substrate decorated with nanostructures of different heights. Those simulations begin with an initial configuration for the complex liquid-vapor-solid system, followed by an equilibrating system at 90 K, and conclude with two different jump temperatures, including 150 and 310 K which are far beyond the critical temperature. The space and time dependences of temperature, pressure, density number, and net evaporation rate are monitored to investigate the phase transition process on a flat surface with and without nanostructures. The simulation results reveal that the nanostructures are of great help to raise the heat transfer efficiency and that evaporation rate increases with the nanostructures' height in a certain range.

No MeSH data available.


Related in: MedlinePlus