Experimental Investigation of the Evaporation and Stability of a Meniscus in a Flat Microchannel

2011 ◽  
Vol 312-315 ◽  
pp. 1178-1183
Author(s):  
Souad Harmand ◽  
Khellil Sefiane ◽  
Rachid Bennacer ◽  
Nicolas Lancial
Keyword(s):  
Experimental Investigation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Evaporation Rate ◽  
Liquid Meniscus ◽  
Line Region ◽  
Three Phase ◽  
Increasing Temperature ◽  
Insight Into

We present the results of an experimental investigation of the evaporation of a liquid meniscus in a high aspect ratio micro-channel. The study investigates evaporation rates of a stationary liquid meniscus in a high aspect ratio microchannel, the wall of which is electrically heated using transparent resistive coating. Four different liquids are used as working fluids. We report on the dependence of the measured overall evaporation rate on the applied power. The results indicate, and consistently, that the evaporation rate increases with the applied power then peaks before declining. In order to gain insight into these results, we used thermographic infra red imaging to map the temperature field on the external wall of the microchannel. The measurements show that there is a good correlation between the maximum in the evaporative rate and the onset of instabilities of the interface. These instabilities, to our mind, are induced by an increasing temperature gradient along the microchannel wall around the three phase contact line region. These instabilities are revealed by a high speed camera used to record the behaviour of the interface during evaporation.

Effect of Nanoparticles on Forming Process of Bubbles in a Nanofluid

2009 ◽  
Author(s):  
Fengmin Su ◽  
Xuehu Ma ◽  
Jiabin Chen
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Ccd Camera ◽  
Experimental Results ◽  
Forming Process ◽  
Three Phase ◽  
Insight Into

An experimental investigation was conducted to determine the effect of nanoparticles on the forming process of bubbles in the gas-liquid-nanoparticle three-phase fluidization. In the experiment, a SiO2-water nanofluid was prepared without any surfactants, and the forming process of bubbles in the nanofluid was observed by the high-speed CCD camera. The experimental results show that the diameter of the formed bubble in the nanofluid is smaller 5% than that in water, and the frequency forming bubbles in the nanofluid is higher than that in water. The investigation can provide an insight into the functionary mechanism of the bubble forming process in the gas-liquid-nanoparticles nanofluids.

High-Speed Additive Manufacturing Through High-Aspect-Ratio Nozzles

JOM ◽  
2018 ◽  
Vol 70 (3) ◽  
pp. 284-291 ◽  
Author(s):  
Leon Shaw ◽  
Mashfiqul Islam ◽  
Jie Li ◽  
Ling Li ◽  
S. M. Imran Ayub
Keyword(s):  
Additive Manufacturing ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed

scholarly journals Numerical Investigation into Flutter and Flutter-Buffet Phenomena for a Swept Wing and a Curved Planform Wing

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Mario Rosario Chiarelli ◽  
Salvatore Bonomo
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Sensitivity Study ◽  
Fuel Saving ◽  
Swept Wing ◽  
Instability Condition ◽  
Aspect Ratios ◽  
Numerical Studies ◽  
Classical Flutter

The results of numerical studies carried out on high-aspect-ratio wings with different planforms are discussed: the transonic regime is analysed for a swept wing and a curved planform wing. The wings have similar aspect ratios and similar aerodynamic profiles. The analyses were carried out by CFD and FE techniques, and the reliability of the numerical aerodynamic results was proven by a sensitivity study. Analysing the performances of the two wings demonstrated that in transonic flight conditions, a noticeable drag reduction can be obtained by adopting a curved planform wing. In addition, for such a wing, the aeroelastic instability condition, consisting in a classical flutter, is postponed compared to a conventional swept wing, for which a flutter-buffet instability occurs. In a preliminary manner, the study shows that, for a curved planform wing, the high speed buffet is not an issue and at the same time notable fuel saving can be achieved.

scholarly journals Designing Model Systems for Enhanced Adhesion

MRS Bulletin ◽  
2007 ◽  
Vol 32 (6) ◽  
pp. 496-503 ◽  
Author(s):  
Edwin P. Chan ◽  
Christian Greiner ◽  
Eduard Arzt ◽  
Alfred J. Crosby
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Model Systems ◽  
Adhesion Forces ◽  
Synthetic Analogues ◽  
Jumping Spiders ◽  
Topographic Features ◽  
Considerable Research ◽  
Insight Into ◽  
Primary Strategy

AbstractNature provides inspiration for enhanced control of adhesion through numerous examples ranging from geckos to jumping spiders. The primary strategy in these examples is the incorporation of patterns, specifically high-aspect-ratio topographic features, to ingeniously maximize adhesion forces while maintaining ease of release. Recently, considerable research efforts have been devoted toward the understanding, development, and optimization of synthetic analogues to these examples in nature. In this article, we provide insight into the mechanisms that lead to enhanced control of interfacial properties through patterning, the strategies that can be used for fabricating synthetic patterns, and an overview of experimental results that have been used to gain understanding and guidance in this emerging field.

A Study on the Characteristics of Micro Deep Hole Machining Processes

2007 ◽  
Vol 364-366 ◽  
pp. 566-571
Author(s):  
Tae Il Seo ◽  
Dong Woo Kim ◽  
Myeong Woo Cho ◽  
Eung Sug Lee
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Printed Circuit Boards ◽  
Hole Drilling ◽  
Deep Hole ◽  
Machining Processes ◽  
Deep Hole Drilling ◽  
Micro Drilling ◽  
Hole Machining

Recently, the trends of industrial products move towards more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is required to perform more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multilayered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. The industries of precision production require smaller holes, high aspect ratio and high speed working for micro deep hole drilling. However the undesirable characteristics of micro drilling is the small signal to noise ratios, wandering motion of drill, high aspect ratio and the increase of cutting force as cutting depth increases. In order to optimize cutting conditions, an experimental study on the characteristics of micro deep hole machining processes using a tool dynamometer was carried out. And additionally, microscope with built-in an inspection monitor showed the relationship between burr in workpieces and chip form of micro drill machining.

Enabling Robust Copper Fill of High Aspect Ratio Through Silicon Vias

2010 ◽  
Vol 2010 (1) ◽  
pp. 000176-000179
Author(s):  
Mark Willey ◽  
Damo Srinivas ◽  
Sesha Varadarajan ◽  
David Porter ◽  
Easwar Srinivasan ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
High Performance ◽  
Process Window ◽  
Seed Technology ◽  
Aspect Ratios ◽  
Reducing Costs ◽  
Electroplating Process ◽  
Silicon Vias

Today's Through Silicon Via (TSV) processes are limited to aspect ratios of 10:1. High performance logic devices drive the need for aspect ratios approaching 20:1 in order to achieve the desired performance while simultaneously reducing costs. The reduced via area required on the wafer enables the designer to utilize less real estate on the die to reduce cost or to potentially add redundant vias to improve yield. However, current conventional processes and techniques are not capable of achieving robust fill on aspect ratios greater than 12:1. This presentation will highlight the technical challenges in achieving robust copper fill on super high aspect ratio TSV structures. Additionally, a compelling, economic solution pathway will be presented that integrates a low temperature conformal high quality dielectric isolation layer, a high step coverage Cu barrier / seed technology and a void free high speed electroplating process with a wide process window that could accelerate the adoption of the high aspect ratio TSV design schemes.

Numerical and Experimental Investigation of Thermomechanical Deformation in High-Aspect-Ratio Electroplated Through-Silicon Vias

2008 ◽  
Vol 155 (12) ◽  
pp. H981 ◽  
Author(s):  
Pradeep Dixit ◽  
Sun Yaofeng ◽  
Jianmin Miao ◽  
John H. L. Pang ◽  
Ritwik Chatterjee ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Through Silicon Vias ◽  
Thermomechanical Deformation ◽  
Silicon Vias
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