Influence of Lateral Restraint on Thermocapillary Migration of Wetting Droplets

2019 ◽  
Author(s):  
Kalichetty Srinivasa Sagar ◽  
K. G. Dwaraknath ◽  
Arvind Pattamatta ◽  
T. Sundararajan
Keyword(s):  
Thin Film ◽  
Temperature Gradient ◽  
Migration Velocity ◽  
Industrial Applications ◽  
Lateral Spread ◽  
Cold Side ◽  
Thermocapillary Force ◽  
Thermocapillary Flows ◽  
Thermocapillary Migration ◽  
Heating And Cooling

Abstract The present study aims at studying the characteristics of thermocapillary migration with varying levels of lateral restraints. A temperature gradient is created by heating and cooling either side of the substrate. When a droplet is placed near hot side it spreads as thin film and migrates towards the cold side. The advancing end assumes the shape of a parabolic rim while the receding end stays as a thin film. It is observed that the droplet decelerates to attain a steady state velocity and undergoes slight acceleration near the cold end of the substrate. The observed velocity trend follows the temperature gradient on the substrate. The velocity increases with the droplet volume and substrate temperature gradient. The liquid viscosity is observed to have a diminishing effect on migration velocity. The effect of lateral spread confinement is studied by performing experimental trails on substrates with different widths. It is found that reducing the substrate width increases the migration velocity due to increased footprint resulting in larger thermocapillary force. The results observed in the present study highlights the importance of thermocapillary flows in many academic and industrial applications.

scholarly journals Experimental Investigation of Mechanical Properties of PVC Polymer under Different Heating and Cooling Conditions

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Sarkawt Rostam ◽  
Alan Kareem Ali ◽  
Firdaws Haidar AbdalMuhammad
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Room Temperature ◽  
Heating Temperature ◽  
Industrial Applications ◽  
Standard Samples ◽  
Heating And Cooling ◽  
Working Environments ◽  
Cooling Conditions ◽  
Temperature Ranges

Due to a widely increasing usage of polymers in various industrial applications, there should be a continuous need in doing research investigations for better understanding of their properties. These applications require the usage of the polymer in different working environments subjecting the material to various temperature ranges. In this paper, an experimental investigation of mechanical properties of polyvinyl chloride (PVC) polymer under heating and cooling conditions is presented. For this purpose standard samples are prepared and tested in laboratory using universal material testing apparatus. The samples are tested under different conditions including the room temperature environment, cooling in a refrigerator, and heating at different heating temperatures. It is observed that the strength of the tested samples decreases with the increasing of heating temperature and accordingly the material becomes softer. Meanwhile the cooling environments give a clear increasing to the strength of the material.

Analytical Study of the Thermal and Optical Properties Effect on the Collinear Deflection Method

2013 ◽  
Vol 811 ◽  
pp. 353-357
Author(s):  
Kuen Tea Park ◽  
Moon G. Lee ◽  
Dae Sik Jeong ◽  
Dong Kwon Kim ◽  
Moo Joong Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
Temperature Gradient ◽  
Probe Beam ◽  
Measurement Techniques ◽  
Important Field ◽  
Property Measurement ◽  
Transparent Materials ◽  
Film Form ◽  
The Ideal

Recently, study of transparent materials, such as thin film form, have an important field for the development of advanced electronic devices. Therefore, the need for the precision thermal property measurement techniques of transparent thin film materials becomes increasing according to the development of these material. The ideal methods for optically measurements of these properties are noncontact method. However, optically measurements are often difficult due to the transparency. So, transparent materials have not enough temperature gradient in the air layer above thin films. To solve this problem, we used the collinear deflection method which is one of the photothermal deflection methods. In the measurement process, both of the pump beam and probe beam are irradiated vertically on the transparent sample. And the probe beam is deflected by refractive index variation of samples due to the temperature gradient inside samples.The purpose of this study is to analyze the effect of thermal and optical properties analytically on the collinear deflection method for variable materials.

Experimental Investigation on PTFE Composites for Journal Bearings

2007 ◽  
Author(s):  
V. Jayaraj ◽  
K. Srinivasan
Keyword(s):  
Thin Film ◽  
Hydrodynamic Lubrication ◽  
Industrial Applications ◽  
Journal Bearings ◽  
Lubricating Oil ◽  
Lubricating Film ◽  
Ideal Situation ◽  
Rolling Element ◽  
Heavy Loads ◽  
Ptfe Composites

Journal bearings are widely used in many industrial applications. In journal bearings, under boundary lubricated conditions, the surfaces are considered to be technically dry or only slightly lubricated, so that the resistance to relative motion is due to the interaction between the highest asperities covered by the boundary film. A thin film of lubricating oil exists under this condition and there is partial metal to metal contact. The ideal situation where the two sliding surfaces are completely separated by a thin film of a viscous fluid or a gas is referred to as hydrodynamic lubrication. In hydrodynamic bearings, due to frequent starting and stopping, misalignment of the shaft with the bearing, application of heavy loads and unexpected sudden non flow of lubricant and such other service conditions result in boundary lubrication by squeezing out the lubricating film or allow the surface asperities to break through the film so that the shaft and bearing are pressed into contact with one another. The maximum wear occurs in fluid film bearings during boundary lubricated conditions. The use of dry bearings has therefore become more essential as it requires practically no lubricant to function. Moreover it is less expensive, resist contamination better compared to rolling element bearings and easier to design.

Electromigration in metals

1977 ◽  
Vol 55 (2) ◽  
pp. 103-115 ◽  
Author(s):  
S. T. Pai ◽  
J. P. Marton
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Elevated Temperature ◽  
Temperature Gradient ◽  
Electrostatic Force ◽  
Electrical Current ◽  
Net Migration ◽  
Sample Position ◽  
Hole Current ◽  
Reversal Temperature

In bulk and thin film metal samples, a net migration of material may take place when electrical current is passed through the sample at an elevated temperature. The migration is due to the passage of electron (or hole) current, the electrostatic force on the metal ions, and the temperature gradient in the sample. The extent and the direction of net migration has not been predicted satisfactorily by existing theories, leaving many unexplained anomalous experimental results. The present work is the development of a generalized theory that contains the main features of previous theories. It can explain all major experimental observations. Its main features include predictions on the temperature and time dependence of migration, its direction, its reversal temperature, and the approximate sample position that is affected most. The theory has been used to interpret available experimental data on a number of electron- and hole-type metals.

Condensation Induced Shock in Thermal/Fluid Systems

2012 ◽  
Author(s):  
Amir Jokar ◽  
Erik W. Christiansen
Keyword(s):  
Shock Waves ◽  
Phase Change ◽  
Air Conditioning ◽  
Industrial Applications ◽  
Governing Equations ◽  
Cooling Systems ◽  
Heating And Cooling ◽  
Fluid Systems ◽  
Air Conditioning Systems ◽  
Effective Life

Phase-change through condensation and evaporation processes takes place in many daily-use heating and cooling systems. However, if these processes experience uncontrolled pressure and temperature conditions, shock waves may be generated. Depending on the strength and conditions of the generated waves, they can decrease the effective life of equipment or even cause devastating destruction. Cavitation and water hammer phenomena are examples of flow issues that are well understood and reported in thermal/fluid systems, although not many studies have been published in open literature on condensation-induced shock (CIS) with the applications in refrigeration and air conditioning systems. This study reviews the limited literature on this topic, analyze the complex CIS phenomenon, derives and solves the governing equations, presents the results of typical conditions that may happen in different residential and industrial applications, and provides ways to avoid devastating incidents that may occur as a result of this phenomena.

Thin-Film In x Al y Ga1 – x – yAs z Sb1 – z/GaSb Heterostructures Grown in a Temperature Gradient

2018 ◽  
Vol 60 (5) ◽  
pp. 890-898 ◽  
Author(s):  
M. L. Lunina ◽  
L. S. Lunin ◽  
V. V. Kalinchuk ◽  
A. E. Kazakova
Keyword(s):  
Thin Film ◽  
Temperature Gradient
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