Molecular Dynamics Simulation of Explosive Boiling on Concave Nanostructured Surface

2018 ◽  
Author(s):  
Pengfei Ji ◽  
Mengzhe He ◽  
Yiming Rong ◽  
Yuwen Zhang ◽  
Yong Tang
Keyword(s):  
Surface Area ◽  
Flat Surface ◽  
Liquid Argon ◽  
Copper Surface ◽  
Heat Transfer Process ◽  
Dynamics Simulation ◽  
Nanostructured Surface ◽  
Explosive Boiling ◽  
Nanostructured Surfaces ◽  
Set Up

Explosive boiling occurs when a liquid film contacts with the wall at extremely high temperature, which is detrimental to continuous heat transfer process. In this paper, five kinds of nanostructured surfaces with equal distance between neighboring nano-concaves and flat surface are set up to study the explosive boiling of liquid argon on copper surface. For all the five cases with concave nanostructured surface, the ratio of concave nanostructured surface area to flat surface area is kept as a constant. The temporal and spatial distributions of temperature, atomic motion and number density are recorded to study the effects of different nanostructured surface designs on explosive boiling. From the perspective of reducing explosive boiling, the most favorable nanostructured surface is determined.

scholarly journals Effect of the Hybrid Hydrophobic-Hydrophilic Nanostructured Surface on Explosive Boiling

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 212
Author(s):  
Ming-Jun Liao ◽  
Li-Qiang Duan
Keyword(s):  
Liquid Film ◽  
Coating Thickness ◽  
Bubble Nucleation ◽  
Onset Temperature ◽  
Dynamics Simulation ◽  
Hydrophilic Surface ◽  
Pillar Width ◽  
Nanostructured Surface ◽  
Explosive Boiling ◽  
Hydrophobic Coating

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.

Molecular dynamics simulation on explosive boiling of liquid argon film on copper nanochannels

2017 ◽  
Vol 113 ◽  
pp. 208-214 ◽  
Author(s):  
Shiwei Zhang ◽  
Feng Hao ◽  
Haimu Chen ◽  
Wei Yuan ◽  
Yong Tang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Liquid Argon ◽  
Dynamics Simulation ◽  
Explosive Boiling

scholarly journals Influence of Nanoscaled Surface Modification on the Reaction of Al/Ni Multilayers

2017 ◽  
Author(s):  
Heike Bartsch ◽  
José Manuel Mánuel ◽  
Rolf Grieseler
Keyword(s):  
Annealing Temperature ◽  
Flat Surface ◽  
Thermal Contact ◽  
Surface Modifications ◽  
Emerging Technology ◽  
Silicon Surfaces ◽  
Nanostructured Surface ◽  
Full Transformation ◽  
Nanostructured Surfaces ◽  
Reference Samples

Sputtered reactive multilayers applied as a heat source in electronic joining processes are an emerging technology. It promises low-stress assembly of components while improving the thermal contact and thus thermal resistance. The use of nanostructures can significantly enhance the adhesion and reliability of joints between different materials. This work presents a phenomenological proof of the hypothesis. Reactive multilayers of nickel and aluminum directly deposited on nanostructured surfaces of silicon wafers and reference samples with flat surface are compared. The investigation of the self-propagating reaction shows a clear influence of the layer thickness, dependent on the multilayer thickness and nanostructure morphology. Rapid thermal annealing results in the formation of Al1.1Ni0.9 phase. The necessary annealing temperature is much higher than this applied for nanofoils, sputtered multilayer or particles. The nanostructured interface seems to hinder the full transformation of the present nickel. On the other hand, the surfaces modification improves adhesion of the formed alloy on silicon surfaces and can thus reduce the strength of joints based on reactive aluminum/nickel multilayer . The use of nanostructured surface modifications is thus a promising approach to realized reliable multi-material joints in complex systems.

Outlet Surface Area Influence in Spiral Casing Design on Centrifugal Fan Performance

2020 ◽  
Vol 5 (1) ◽  
pp. 37-41
Author(s):  
Ardit Gjeta ◽  
Lorenc Malka
Keyword(s):  
Surface Area ◽  
Static Pressure ◽  
Total Efficiency ◽  
Centrifugal Fan ◽  
Recovery Coefficient ◽  
Fan Performance ◽  
Parameter Variations ◽  
Set Up ◽  
Spiral Casing ◽  
Pressure Recovery Coefficient

In this paper, the effect of the outlet surface area of the spiral casing on the performance of a centrifugal fan was investigated using open source CFD software OpenFOAM [1]. An automized loop with RANS and data post-processing is set up using Matlab, for allowing a large number of parameter variations. The effect was analyzed as a function of total pressure loss and static pressure recovery coefficient and on total efficiency as well.

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