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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

Number density profiles for the case with a 150 K heated source. (a) Surface 0, (b) surface 1, (c) surface 3, and (d) surface 4.
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Fig12: Number density profiles for the case with a 150 K heated source. (a) Surface 0, (b) surface 1, (c) surface 3, and (d) surface 4.

Mentions: The density profile of the argon regions in the z-axis for all surfaces in the low temperature case is illustrated in Figure 12. It can be observed that for all surfaces, the number density of argon molecules gradually decreases with time, which indicates that the liquid molecules reduce slowly with low generation rate of evaporation. It is important to note that for surfaces with nanostructures, the number of non-evaporative liquid molecules increases with height of the nanoposts, which results from the phenomenon that a few molecular layers are absorbed on the nanostructures. The insets in Figure 12b,c,d are number densities in upper regions in the z direction at different times; from these insets, it can be obtained that the evaporated vapor will gradually enter into a higher region to make the density number increase when the time goes on.Figure 12


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)

Number density profiles for the case with a 150 K heated source. (a) Surface 0, (b) surface 1, (c) surface 3, and (d) surface 4.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig12: Number density profiles for the case with a 150 K heated source. (a) Surface 0, (b) surface 1, (c) surface 3, and (d) surface 4.
Mentions: The density profile of the argon regions in the z-axis for all surfaces in the low temperature case is illustrated in Figure 12. It can be observed that for all surfaces, the number density of argon molecules gradually decreases with time, which indicates that the liquid molecules reduce slowly with low generation rate of evaporation. It is important to note that for surfaces with nanostructures, the number of non-evaporative liquid molecules increases with height of the nanoposts, which results from the phenomenon that a few molecular layers are absorbed on the nanostructures. The insets in Figure 12b,c,d are number densities in upper regions in the z direction at different times; from these insets, it can be obtained that the evaporated vapor will gradually enter into a higher region to make the density number increase when the time goes on.Figure 12

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