Nano scale dynamics of bubble nucleation in confined liquid subjected to rapid cooling: Effect of solid-liquid interfacial wettability

2017 ◽  
Author(s):  
Mohammad Nasim Hasan ◽  
Kazi Fazle Rabbi ◽  
K. M. Mukut ◽  
Saiful Islam Tamim ◽  
A. H. M. Faisal
Keyword(s):  
Bubble Nucleation ◽  
Cooling Effect ◽  
Rapid Cooling ◽  
Nano Scale ◽  
Solid Liquid

Unexpected Homogeneous Bubble Nucleation near a Solid–Liquid Interface

2018 ◽  
Vol 122 (50) ◽  
pp. 28712-28716 ◽  
Author(s):  
Yoko Tomo ◽  
Qin-Yi Li ◽  
Tatsuya Ikuta ◽  
Yasuyuki Takata ◽  
Koji Takahashi
Keyword(s):  
Bubble Nucleation ◽  
Liquid Interface ◽  
Solid Liquid Interface ◽  
Solid Liquid

scholarly journals Self-Consolidation Mechanism of Nanostructured Ti5Si3Compact Induced by Electrical Discharge

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
W. H. Lee ◽  
Y. W. Cheon ◽  
Y. H. Jo ◽  
J. G. Seong ◽  
Y. J. Jo ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Single Phase ◽  
External Pressure ◽  
Surface Oxide ◽  
Complete Conversion ◽  
Rapid Cooling ◽  
Pinch Force ◽  
Powder Particles ◽  
Solid Bulk ◽  
Solid Liquid

Electrical discharge using a capacitance of 450 μF at 7.0 and 8.0 kJ input energies was applied to mechanical alloyed Ti5Si3powder without applying any external pressure. A solid bulk of nanostructured Ti5Si3with no compositional deviation was obtained in times as short as 159 μsec by the discharge. During an electrical discharge, the heat generated is the required parameter possibly to melt the Ti5Si3particles and the pinch force can pressurize the melted powder without allowing the formation of pores. Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3compact. Three stepped processes during an electrical discharge for the formation of nanostructured Ti5Si3compact are proposed: (a) a physical breakdown of the surface oxide of Ti5Si3powder particles, (b) melting and condensation of Ti5Si3powder by the heat and pinch pressure, respectively, and (c) rapid cooling for the preservation of nanostructure. Complete conversion yielding a single phase Ti5Si3is primarily dominated by the solid-liquid mechanism.

Nanobubbles on a Very Flat Hydrophobic Surface Prepared by Self-Assembled Monolayers

2013 ◽  
Author(s):  
Takashi Nishiyama ◽  
Koji Takahashi ◽  
Yasuyuki Takata
Keyword(s):  
Heat Transfer ◽  
Gaseous Phase ◽  
Hydrophobic Surface ◽  
Bubble Nucleation ◽  
Liquid Interface ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Solid Liquid Interface ◽  
Solid Liquid

Boiling is one of the most effective heat transfer methods due to its high heat transfer coefficient. Therefore, boiling heat transfer plays a very important role for various applications in many technological and industrial areas. However, a very complex mechanism of boiling, especially bubble nucleation, is still not sufficiently understood. On the other hand, numerous experiments have revealed the existence of soft domains that called nanobubbles at the solid-liquid interface. In this study, to investigate the influence of the solid-liquid interface nanobubbles on the bubble nucleation, an atomic force microscope (AFM) is used to characterize the morphology of nanobubbles. In order to separate the effect of wettability of a solid surface from that of surface structure, a very flat hydrophobic surface was prepared. 1H,1H,2H,2H-Perfluoro-n-octylphosphonic acid (FOPA) formed the interface of hydrophobic self-assembled monolayers (SAMs). As the result of AFM measurement, many nanobubbles about 100 nm in diameter and 30 nm thick are observed at the interface of the FOPA surface and the pure water. In addition, to prove the existence of gaseous phase, the heat conductance measurement by time-domain thermoreflectance method (TDTR) was introduced. TDTR is an ultrafast optical pump probe technique well suited for thermal measurement of thin films. It enables to resolve the thermal conductivity of the thin film and the thermal conductance of the interface. If nanobubbles are the gaseous phase, the big change of interface heat thermal resistance will be seen and the TDTR signal should also change. The effectiveness of a TDTR to confirm the existence of nanobubbles is shown by the model simulation of TDTR. A clear difference is seen in TDTR signal by the existence of only 1 nm gaseous phase. After confirming the existence of nanobubbles by AFM measurement, it can be proved that the nanobubbles are truly gaseous phase of the TDTR measurement.

Homogeneous Nucleation Boiling During Jet Impingement Quench of Hot Surfaces

2010 ◽  
Author(s):  
Mohammad Nasim Hasan ◽  
Masanori Monde ◽  
Yuichi Mitsutake
Keyword(s):  
Homogeneous Nucleation ◽  
Control Volume ◽  
Internal Heat ◽  
Jet Impingement ◽  
Bubble Nucleation ◽  
Liquid Jet ◽  
Liquid Temperature ◽  
Time Duration ◽  
Solid Liquid ◽  
Explosion Condition

In the present study, we focused on the rapid liquid heating process and the subsequent boiling explosion that occurs when a liquid jet comes in contact with a very hot surface during jet impingement quenching. Assuming the liquid jet as 1-D semi-infinite solid during its brief contact with the surface, a model has been proposed based on the ideas of 1-D heat conduction and homogeneous nucleation. In this model, a liquid control volume having the size of a critical cluster at the boundary is considered and the corresponding energy balance is obtained by accounting for the two parallel competing processes that takes place inside the liquid control volume, namely, transient external heat deposition and internal heat consumption due to liquid superheat, bubble nucleation and subsequent growth. Results obtained are presented in terms of the liquid temperature escalation within the control volume, the limit of maximum attainable liquid temperature and the time necessary to reach the temperature limit at the boiling explosion. The boiling explosion condition as defined in the present model is also compared with the theoretical boiling explosion condition denoted by the upper bound of evaporative heat flux across the liquid-vapor interface, qmax,max. The time duration of the solid-liquid contact prior to the boiling explosion at different surface temperatures as obtained by the proposed model may be helpful for better understanding the possible surface temperature oscillations due to repetitive solid-liquid contact in the first few microseconds of jet impingement quenching.

scholarly journals RAPID COOLING EFFECT IN POLYPROPYLENE MELT SPINNING-INFLUENCE OF STRESS

1976 ◽  
Vol 32 (6) ◽  
pp. T248-T253
Author(s):  
Jiro Shimizu ◽  
Kozo Shimazaki
Keyword(s):  
Melt Spinning ◽  
Cooling Effect ◽  
Rapid Cooling ◽  
Polypropylene Melt

Wettability Gradients on Graphene to Drive Bubble Motion

2019 ◽  
Author(s):  
Hongyang Yu ◽  
Yu Zhao ◽  
Jingjie Sha ◽  
Yunfei Chen
Keyword(s):  
Channel Wall ◽  
Md Simulation ◽  
Hydrophobic Surface ◽  
Bubble Nucleation ◽  
Surface Wettability ◽  
Bubble Motion ◽  
Unidirectional Movement ◽  
Nucleation Sites ◽  
Direction Of Movement ◽  
Solid Liquid

Abstract The molecular dynamics (MD) method is employed to simulate thermal bubble nucleation processes confined in graphene nanochannels. It is found that nucleation sites depend strongly on the different solid-liquid interfacial properties in various systems. In this work, the thermal bubble nucleates on the graphene surface, on which the interaction between liquid molecules and channel wall is weak relatively. It is demonstrated that the hydrophobic surface would make thermal bubble to initiate easier. A conceptual design about surface wettability gradient was proposed, which can break the equilibrium state of a bubble and induce its unidirectional movement on the surface. Moreover, MD simulation showed that through a continuous gradient of surface wettability, the direction of movement is under control. These findings provide us with a method in device design for applications of self-controlling motion of bubble down to nanoscale and other wettability-enabled actuators.

An Outline of Methods in Machining Curved Hole

2011 ◽  
Vol 328-330 ◽  
pp. 181-185
Author(s):  
Ying Ping Qian ◽  
Yin He ◽  
Ju Hua Huang ◽  
Xi Zhi Zhou
Keyword(s):  
Injection Molding ◽  
Cooling Effect ◽  
Cooling Channel ◽  
Conformal Cooling Channel ◽  
Rapid Cooling ◽  
Conformal Cooling ◽  
Cooling Stage ◽  
Curved Hole

Cooling stage is a key stage of injection molding. It affects both the quality and efficiency of injection molding of products. Conformal cooling channel, due to its advantages in uniform cooling and rapid cooling, could improve the cooling effect obviously. Therefore, study on methods of machining curved hole are proposed to be used for practice. In this thesis, some methods of machining curved hole and their features in general were introduced.

The effects of bio-inspired micro/nano scale structures on anti-icing properties

Soft Matter ◽  
2021 ◽  
Author(s):  
Hongtao Gao ◽  
Yiming Jian ◽  
Yuying Yan
Keyword(s):  
Heat Transfer ◽  
Contact Area ◽  
Nano Scale ◽  
Scale Structures ◽  
Solid Liquid

The rough structure of the surface-caused reduction of the solid–liquid contact area, which caused a reduction in the heat transfer and probability of icing.

Sign in / Sign up

Export Citation Format

Share Document