Molecular Dynamics Study on Explosive Boiling of Thin Liquid Argon Film on Nanostructured Surface Under Different Wetting Conditions

2015 ◽  
Author(s):  
Sheikh Mohammad Shavik ◽  
Mohammad Nasim Hasan ◽  
A. K. M. Monjur Morshed
Keyword(s):  
Molecular Dynamics ◽  
Liquid Film ◽  
Solid Surface ◽  
Solid Wall ◽  
Thin Liquid Film ◽  
Liquid Argon ◽  
Spatial And Temporal Variation ◽  
Phase System ◽  
Explosive Boiling ◽  
System Pressure

Molecular dynamics (MD) simulations have been performed to investigate the boiling phenomena of thin liquid film adsorbed on a nanostructured solid surface with particular emphasis on the effect of wetting condition of the solid surface. The molecular system consists of liquid and vapor argon, and solid platinum wall. The nanostructures which reside on top of the solid wall have shape of rectangular block. The solid-liquid interfacial wettability, in other words whether the solid surface is hydrophilic or hydrophobic has been altered for different cases to examine its effect on boiling phenomena. The initial configuration of the simulation domain comprised a three phase system (solid platinum, liquid argon and vapor argon) which was equilibrated at 90 K. After equilibrium period, the wall temperature was suddenly increased from 90 K to 250 K which is far above the critical point of argon and this initiates rapid or explosive boiling. The spatial and temporal variation of temperature and density as well as the variation of system pressure with respect to time were closely monitored for each case. The heat flux normal to the solid surface was also calculated to illustrate the effectiveness of heat transfer for different cases of wetting conditions of solid surface. The results show that the wetting condition of surface has significant effect on explosive boiling of the thin liquid film. The surface with higher wettability (hydrophilic) provides more favorable conditions for boiling than the low-wetting surface (hydrophobic) and therefore, liquid argon responds quickly and shifts from liquid to vapor phase faster in case of hydrophilic surface.

Molecular Dynamics Study on Explosive Boiling of Thin Liquid Argon Film on Nanostructured Surface Under Different Wetting Conditions

2016 ◽  
Vol 138 (1) ◽  
Author(s):  
Sheikh Mohammad Shavik ◽  
Mohammad Nasim Hasan ◽  
A. K. M. Monjur Morshed
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Liquid Film ◽  
Solid Surface ◽  
Thin Liquid Film ◽  
Liquid Argon ◽  
Spatial And Temporal Variation ◽  
Phase System ◽  
Hydrophilic Surface ◽  
Explosive Boiling

Molecular dynamics (MDs) simulations have been performed to investigate the boiling phenomena of thin liquid film adsorbed on a nanostructured solid surface with particular emphasis on the effect of wetting condition of the solid surface. The molecular system consists of liquid and vapor argon and solid platinum wall. The nanostructures which reside on top of the solid wall have shape of rectangular block. The solid–liquid interfacial wettability, in other words whether the solid surface is hydrophilic or hydrophobic, has been altered for different cases to examine its effect on boiling phenomena. The initial configuration of the simulation domain comprises a three-phase system (solid platinum, liquid argon, and vapor argon), which was equilibrated at 90 K. After equilibrium period, the wall temperature was suddenly increased from 90 K to 250 K which is far above the critical point of argon and this initiates rapid or explosive boiling. The spatial and temporal variation of temperature and density as well as the variation of system pressure with respect to time were closely monitored for each case. The heat flux normal to the solid surface was also calculated to illustrate the effectiveness of heat transfer for different cases of wetting conditions of solid surface. The results show that the wetting condition of surface has significant effect on explosive boiling of the thin liquid film. The surface with higher wettability (hydrophilic) provides more favorable conditions for boiling than the low-wetting surface (hydrophobic), and therefore, the liquid argon responds quickly and shifts from liquid to vapor phase faster in the case of hydrophilic surface. The heat transfer rate is also much higher in the case of hydrophilic surface.

Nanostructures Length Effect on Phase Transition Phenomena of Ultra-Thin Liquid Film From a Nanostructured Surface: A Molecular Dynamics Study

2011 ◽  
Author(s):  
A. K. M. M. Morshed ◽  
T. C. Paul ◽  
Jamil A. Khan
Keyword(s):  
Molecular Dynamics ◽  
Film Thickness ◽  
Liquid Film ◽  
Solid Surface ◽  
Thin Liquid Film ◽  
Liquid Argon ◽  
Liquid Film Thickness ◽  
Dynamics Simulation ◽  
Phase System ◽  
Three Phase

A molecular dynamics simulation has been employed to investigate the boiling phenomena of few molecular-layer thin liquid-film adsorbed on a nanoscale roughened solid surface. The molecular system comprises of three phase system: solid platinum wall, liquid argon and argon vapor. A few layer of liquid argon has been placed on the nanoposts decorated solid surface where nanoposts ensemble surface roughness. Nanoposts height has been varied keeping liquid film thickness constant to capture three scenario: (i) Liquid-film thickness is higher than the height of the nanoposts (ii) Liquid-film and nanoposts are of same height (iii) Liquid-film thickness is less than the height of the nanoposts. Rest of the simulation box space has been filled with argon vapor. The simulation starts from the equilibrium three phase system and then suddenly the wall is heated to a higher temperature which resembles an ultra fast laser heating. Two different jump temperatures has been selected: one is a few degrees above the boiling point to initiate normal evaporation and the other one is far above the critical point temperature to initiate explosive boiling. Simulation results indicate nanostructures play significant role in both the cases. Argon responds very quickly in the nanoposts decorated surface and evaporation rate increases with the nanoposts height. Different boiling behavior has been observed for the nanoposts decorated surface.

Effect of heat source temperature, nanostructure, and wettability on explosive boiling of ultra-thin liquid argon film over graphene substrate: a molecular dynamics study

2020 ◽  
Vol 16 ◽  
Author(s):  
Haiyan Zhang ◽  
Cunhui Li ◽  
Yi Wang ◽  
Yingmin Zhu ◽  
Weidong Wang
Keyword(s):  
Heat Transfer ◽  
Phase Transition ◽  
Heat Source ◽  
Liquid Film ◽  
Substrate Surface ◽  
Thin Liquid Film ◽  
Liquid Argon ◽  
Explosive Boiling ◽  
Source Temperature ◽  
Heat Source Temperature

Background: The study on explosive boiling phenomenon has received increasing attention because it involves many industries, such as advanced micro-, nano-electromechanical and nano-electronic cooling systems, laser steam cleaning and so on. Objective: In present work, the explosive boiling of ultra-thin liquid film over two-dimensional nanomaterial surface in confined space with particular emphasis under the three different influencing factors: various heights of nanostructures, various wetting conditions of solid-liquid interface as well as various heat source temperatures. Methods: Molecular Dynamics simulations (MDs) in present work have been adopted to simulate the whole explosive boiling process. Results: For different heat source temperature case, the higher the heat temperature is, the less time the explosive boiling spends after relaxation. For nanostructure case, nanostructure surface significantly increases heat transfer rate and then leads to the increase of phase transition rate of explosive boiling. For different wetting property case, the increase of surface wettability results in increase of phase transition to some degree. Conclusion: The addition of nanostructures, the higher heat source temperature and good wettability between thin liquid film and substrate surface dramatically improve thermal heat transfer from solid surface to liquid film, which will obviously give rise to explosive boiling occur. in addition, the non-vaporized argon layer still exists in these three factors in spite of continuous thermal transmission from substrate surface to liquid argon film adjacent to solid surface even other vaporized argon atoms.

Molecular Dynamics Simulation of Evaporation of a Thin Liquid Argon Layer in a Closed System

2003 ◽  
Author(s):  
Y. W. Wu ◽  
Chin Pan
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Liquid Film ◽  
Closed System ◽  
Thin Liquid Film ◽  
Liquid Argon ◽  
Dynamics Simulation ◽  
Jones Potential ◽  
Evaporation And Condensation ◽  
Simulation Based

Evaporation of a thin liquid film is of significant fundamental importance for both science and engineering applications. This work investigates the evaporation of a thin liquid argon layer into vacuum employing molecular dynamics simulation based on the Lennard-Jones potential. The simulation results demonstrate that the net evaporation rate of an ultra-thin liquid film into vacuum in a closed system may be modeled by the balance of evaporation and condensation based on the Schrage model. The evaporation/condensation coefficient and the non-Maxwellian factor may thus be evaluated. However, the coefficient thus obtained is sensitive to the dimension in the direction normal to the surface. It is also found that the mean temperature for the interface region is 2–3 K lower, while the temperature fluctuations are more violent, than that inside the liquid.

A molecular dynamics study of heat transfer over an ultra-thin liquid film with surfactant between solid surfaces

2019 ◽  
Vol 126 (18) ◽  
pp. 185302 ◽  
Author(s):  
Yuting Guo ◽  
Donatas Surblys ◽  
Yoshiaki Kawagoe ◽  
Hiroki Matsubara ◽  
Taku Ohara
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Solid Surfaces

Linear Stability of Thin Liquid Film On Solid Surface Under Effect of Apolar and Electrostatic Forces

2012 ◽  
Author(s):  
Mohanad El–Harbawi ◽  
Luqman Chuah Abdullah ◽  
Shean Yaw Thomas Choong ◽  
Siti Aslina Hussain ◽  
Azni Idris
Keyword(s):  
Liquid Film ◽  
Linear Stability ◽  
Solid Surface ◽  
Thin Liquid Film ◽  
Navier Stokes ◽  
Electrostatic Forces

Kestabilan lapisan tipis cecair pada permukaan pepejal di bawah kuasa kutub dan elektrostatik dikaji. Aliran ditunjukkan oleh persamaan Navier–Stokes dua dimensi dipasangkan dengan persamaan penerusan serta digabungkan dengan garisan sempadan. Lapisan tipis adalah dimodelkan sebagai cecair Newtonian dua dimensi ketumpatan, ρ dan kelikatan, μ mengalir pada permukaan mendatar. Lapisan tebal purata, h0 adalah dianggap cukup tebal untuk mengabaikan kesan graviti dan dihadkan oleh gas pasif serta ditambah pada sisinya kepada infiniti (model dua dimensi). Kuasa jasad pada persamaan Navier–Stokes telah diubahsuai dengan mengambil kira interaksi di antara (kuasa kutub dan elektrostatik) lapisan cecair dengan permukaan pepejal disebabkan oleh kuasa kutub dan elektrostatik. Pengubahsuaian persamaan Navier–Stokes dengan gabungan garisan sempadan diselesaikan dengan menggunakan persamaan panjang gelombang untuk mendapatkan persamaan tidak lurus evolusi permukaan–permukaan lapisan. Bahagian kuasa elektrostatik adalah lebih besar dalam nilai kuasa kutub dan berpengaruh terhadap sifat lapisan tipis serta kesan utama pada sifat–sifat tenaga bebas berlebihan, kadar penambahan, kadar penambahan maksimum, nombor gelombang natural, nombor gelombang berpengaruh dan masa pecahan. Maka, teori linear adalah kurang menunjukkan sifat-sifat kestabilan lapisan. Pengiraan menunjukkan bahawa kuasa kutub dan elektrostatik hanya boleh digunakan untuk penghasilan lapisan mendatar dengan ketebalan h0

Instantaneous Optical Measurement of the Temperature at the Interface Between a Wall and a Thin Liquid Film

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Brian E. Fehring ◽  
Roman W. Morse ◽  
Jason Chan ◽  
Kristofer M. Dressler ◽  
Evan T. Hurlburt ◽  
...  
Keyword(s):  
Laser Beam ◽  
Liquid Film ◽  
Solid Wall ◽  
Incident Angle ◽  
Thin Liquid Film ◽  
Index Of Refraction ◽  
High Temporal Resolution ◽  
Flow Measurements ◽  
Vapor Interface ◽  
Liquid Vapor

Abstract Instantaneous temperature measurements at the interface between a solid wall and a thin, unsteady liquid film are performed using thermoreflectance, a nonintrusive optical technique with high temporal resolution. A laser beam is directed at a wall–liquid interface, and the intensity of the light reflected at that interface is measured by a photodiode. The intensity of the reflected light varies with the index of refraction of the liquid at the wall. The index of refraction is a function of temperature, which enables the instantaneous measurement of the wall temperature. In the presence of thin liquid films, reflections from the liquid–vapor interface at the free surface of the film generate noise in the measurements. We demonstrate that orienting the laser beam at a large incident angle, close to total internal reflection, minimizes noise from the liquid–vapor interface while increasing the sensitivity of the measurement. The thermoreflectance technique is validated in an unsteady two-phase annular flow. Measurements of temperature fluctuations less than 1 K in amplitude are achieved, with an uncertainty of 0.1 K.

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