scholarly journals Liquid-solid contact state and fluctuation of the vapor film thickness of a drop impinging on a heated surface.

1988 ◽  
Vol 21 (5) ◽  
pp. 463-468 ◽  
Author(s):  
SHIGEAKI INADA ◽  
YOSHIKI MIYASAKA ◽  
KENJI SAKAMOTO ◽  
KEIJI HOJO
Keyword(s):  
Film Thickness ◽  
Heated Surface ◽  
Vapor Film ◽  
Solid Contact ◽  
Contact State

Recent Progress in Disposable Ion-Selective Sensors for Environmental Applications

2012 ◽  
Vol 77 ◽  
pp. 65-70 ◽  
Author(s):  
Giusy Matzeu ◽  
Claudio Zuliani ◽  
Dermot Diamond
Keyword(s):  
Film Thickness ◽  
Recent Progress ◽  
Low Cost ◽  
Contact Layer ◽  
Ion Selective Electrodes ◽  
Complex Relationship ◽  
Solid Contact ◽  
Materials Used ◽  
Deposition Techniques

Solid-contact Ion Selective Electrodes (SC-ISEs) for the detection of lead are prepared on screen printed substrates in order to have low-cost and disposable sensors which may be useful in long-term environmental monitoring. It is shown that the materials used as solid contact layer, the deposition techniques and their thickness affect greatly the performances of the sensors. Poly(3-octylthiophene-2,5-diyl) (POT) and poly-3,4-ethylenedioxithiophene (PEDOT) are employed in this investigation. A trend showing an optimum is found for sensors prepared with POT as the batch reproducibility depends on the amount drop-cast, i.e., thickness. In case of PEDOT which is grown amperometrically the trend is more complex but an optimum for the batch reproducibility is again found depending on the current density. In the latter case, the film thickness and the overoxidation degree of the polymer probably concur in determining a more complex relationship.

Analysis of EHL Circular Contact Start Up: Part I—Mixed Contact Model With Pressure and Film Thickness Results

2000 ◽  
Vol 123 (1) ◽  
pp. 67-74 ◽  
Author(s):  
Jiaxin Zhao ◽  
Farshid Sadeghi ◽  
Michael H. Hoeprich
Keyword(s):  
Film Thickness ◽  
Contact Region ◽  
Elastohydrodynamic Lubrication ◽  
Contact Problems ◽  
Iteration Scheme ◽  
Mixed Lubrication ◽  
Contact Forces ◽  
Solid Contact ◽  
Start Up ◽  
Lubricated Contact

In this paper a model is presented to investigate the start up condition in elastohydrodynamic lubrication. During start up the lubrication condition falls into the mixed lubrication regime. The transition from solid contact to lubricated contact is of importance when investigating the start up process and its effects on bearing performance. The model presented uses the multigrid multilevel method to solve the lubricated region of the contact and a minimization of complementary energy approach to solve the solid contact region. The FFT method is incorporated to speed up the film thickness calculation. An iteration scheme between the lubrication and the solid contact problems is used to achieve the solution of the mixed lubrication contact problem. The results of start up with smooth surfaces are provided for the case when speed increases from zero to desired speed in one step and the case when speed is linearly increased to desired speed. The details of the transition from full solid contact to full lubricated contact in EHL start up are presented. The change of pressure and film thickness as well as contact forces and contact areas are discussed.

Liquid–Solid Contact State in Subcooled Pool Transition Boiling System

1986 ◽  
Vol 108 (1) ◽  
pp. 219-221 ◽  
Author(s):  
S. Inada ◽  
Y. Miyasaka ◽  
S. Sakumoto ◽  
G. R. Chandratilleke
Keyword(s):  
Solid Contact ◽  
Contact State

Effects of Heating Surface Materials on a Liquid–Solid Contact State in a Sessile Drop-Boiling System

1993 ◽  
Vol 115 (1) ◽  
pp. 222-230 ◽  
Author(s):  
S. Inada ◽  
W.-J. Yang
Keyword(s):  
High Speed ◽  
Sessile Drop ◽  
Bubble Radius ◽  
Heating Surface ◽  
Experimental Investigations ◽  
High Speed Photography ◽  
Solid Contact ◽  
Contact State ◽  
Interfacial Pressure ◽  
The Relationship

Three experimental investigations are performed on the liquid–solid contact state at the instant when a liquid comes in contact with a heating surface in the transition-boiling regime between the maximum evaporation rate point and the spheroidal state: (1) measuring the piezoelectric potential by means of a quartz oscillator being placed on the heating surface, (2) monitoring the boiling sound generated at the instant of liquid–solid contact using a condenser microphone, and (3) observation of drop behavior, by means of high-speed photography. The information obtained from these three investigations is synthesized to quantify the liquid–solid contact state. The study has disclosed the roles of thermal properties and heating surface temperatures on the endurance time of the instantaneous liquid–solid contact state and the relationship between the critical bubble radius and the measured vapor–liquid interfacial pressure difference.

A Numerical and Experimental Investigation of a Gas Propelled Liquid Droplet Impinging Onto a Heated Surface

2011 ◽  
Author(s):  
Andres Diaz ◽  
Alfonso Ortega
Keyword(s):  
Kinetic Energy ◽  
Contact Area ◽  
Liquid Droplet ◽  
Heated Surface ◽  
Spray Cooling ◽  
High Heat Flux ◽  
Solid Contact ◽  
Droplet Spreading ◽  
Air Jet ◽  
The Impact

Due to the higher rates of heat transfer and the spatial homogeneity of heat removal that can be achieved with spray cooling, these systems have been widely proposed for cooling high heat flux electronics. In particular, gas-assisted spray cooling systems, in which a vapor phase jet propels the liquid phase droplets to a target surface, have been shown to be even more efficient in removing heat than sprays consisting of droplets alone. However, in all the studies found in the literature, in which the basic problem has been approached as a single-droplet event, only the behavior of a free falling droplet has been studied. To date, there is no fundamental investigation of the physics of gas or vapor-assisted spray cooling. To study this problem an experimental and numerical investigation of the deformation process of a liquid droplet transported by a gas stream impinging on a heated surface was performed. A preliminary study [1] has shown that increasing air jet velocities leads to an augmentation in liquid-solid contact area. Nevertheless, for low We*, the increase in droplet spreading diameter is only a consequence of the increase in droplet kinetic energy before the impact rather than the pressure and shear stress imposed by the gas during the spreading. An order of magnitude analysis showed that shear effects are negligible compared to the normal pressure of the jet. A first order analytical model of the droplet spreading behavior indicated that the jet stagnation pressure acting on the droplet surface becomes important at relatively low Weo and higher We* by contributing to the reduction in liquid film thickness and to the augmentation in liquid-solid contact area. It was shown that the work done by the gas stream in deforming the liquid droplet must be at least 10% of the initial kinetic energy of the droplet to start having a significant effect on the droplet deformation during the early stage of impact.

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