Dynamics of explosive boiling of a droplet

1988 ◽  
Vol 31 (9) ◽  
pp. 2554-2561 ◽  
Author(s):  
D. L. Frost
Keyword(s):  
2001 ◽  
Vol 32 (1-3) ◽  
pp. 8
Author(s):  
V. V. Ovchinnikov ◽  
B. P. Avksentyuk
Keyword(s):  

2002 ◽  
Vol 33 (5-6) ◽  
pp. 9
Author(s):  
V. V. Ovchinnikov ◽  
B. P. Avksentyuk
Keyword(s):  

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 212
Author(s):  
Ming-Jun Liao ◽  
Li-Qiang Duan

The influence of different wettability on explosive boiling exhibits a significant distinction, where the hydrophobic surface is beneficial for bubble nucleation and the hydrophilic surface enhances the critical heat flux. Therefore, to receive a more suitable surface for the explosive boiling, in this paper a hybrid hydrophobic–hydrophilic nanostructured surface was built by the method of molecular dynamics simulation. The onset temperatures of explosive boiling with various coating thickness, pillar width, and film thicknesses were investigated. The simulation results show that the hybrid nanostructure can decrease the onset temperature compared to the pure hydrophilic surface. It is attributed to the effect of hydrophobic coating, which promotes the formation of bubbles and causes a quicker liquid film break. Furthermore, with the increase of the hydrophobic coating thickness, the onset temperature of explosive boiling decreases. This is because the process of heat transfer between the liquid film and the hybrid nanostructured surface is inevitably enhanced. In addition, the onset temperature of explosive boiling on the hybrid wetting surface decreases with the increase of pillar width and liquid film thickness.


2020 ◽  
Vol 35 ◽  
pp. 18-28
Author(s):  
Muhammad Rubayat Bin Shahadat ◽  
A.K.M.M. Morshed

Non-equilibrium molecular dynamics simulations have been employed to study the explosive boiling phenomena of water over a hot copper plate. The molecular system was comprised of three sections: solid copper wall, liquid water, and water vapor. A few layers of the liquid water were placed on the solid Cu surface. The rest of the simulation box was filled with water vapor. Initially, the water molecules were equilibrated by using Berendsen thermostat at 298 K. Then heat was given to the copper plate at different temperatures so that explosive boiling occurs. After achieving the equilibrium by performing the previous two steps, the liquid water at 298 K is suddenly dropped on the hot plate. NVE ensemble was used in the simulation and the temperature of the copper plate was controlled to different temperatures with phantom atom thermostat. Four temperatures (400K, 500K, 650 K and 1000K) were taken to study the explosive boiling. The simulation results show that, the explosive boiling temperature of water on Cu plate is 500 K temperature. At this point, the energy flux was found 1.79x108 J/m3 which is very promising with the experimental results. Moreover, if the temperature of the surface was increased the explosive boiling occurred at a faster rate. The simulation results also show that explosive boiling occurs earlier for the hydrophilic surface than hydrophobic surface as for the hydrophilic surface the water attracted the Cu plate more than the hydrophobic surface and so the amount of energy transfer is more for the hydrophilic surface.


Author(s):  
Sheikh Mohammad Shavik ◽  
Mohammad Nasim Hasan ◽  
A. K. M. Monjur Morshed

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.


Author(s):  
Zhaoyi Dong ◽  
Xiulan Huai ◽  
G.-X. Wang

Liquid nitrogen (LN2) was widely applied in many areas, but researches on the boiling behavior under the transient high heat flux have not been reported. In this paper, the high power short pulse duration laser was used to heat the saturated LN2 rapidly, and the high-speed photography aided by the spark light system was employed to take series of photos which displayed the process of LN2’s boiling behavior under such conditions. At the same time, a special temperature measuring system was applied to record the temperature variation of the heating surface. The experimental result disclosed that at the earlier stage of laser heating, an explosive boiling would happen within LN2. After the newly-defined changeover time, the conventional boiling behavior would follow. Therefore the changeover time became an important index to distinguish these two kinds of boiling behaviors. By analyzing the temperature variation of the heating surface, it is found that the latent heat released by the crack of bubbles in explosive boiling is an important factor that greatly influences the boiling heat transfer mechanism.


Author(s):  
Yu Zou ◽  
Xiulan Huai

Molecular dynamics simulations are carried out to study the energy conversion in the homogeneous nucleation processes of the explosive boiling caused by laser heating. Liquid nitrogen and water are investigated as the working fluid. Velocity scaling method is applied to realize the laser heating process. Three influencing factors, the heat quantity into the system, the area of the laser heating zone and the initial equilibrium temperature of the liquid are analyzed. It is found that the conversion ratio of energy between heat quantity and potential energy is from 66% to 78% in the process of laser heating. The influence of the heat quantity into the system on the energy conversion of liquid nitrogen is the same in trend as that of water. The influence of the initial equilibrium temperature and the area of the laser heating zone on the liquid nitrogen is less than that of water. The difference of energy conversion between water and liquid nitrogen is pretty dramatic, which is because of the hydrogen bond formed by the Coulombic interaction among water molecules.


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