Experimental Study on Frost Structure on Surfaces With Different Hydrophilicity: Density and Thermal Conductivity

2003 ◽  
Vol 125 (1) ◽  
pp. 84-94 ◽  
Author(s):  
Jongmin Shin ◽  
Alexei V. Tikhonov ◽  
Cheolhwan Kim
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Surface Energy ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Test Time ◽  
Visualization System ◽  
Conductivity Increase ◽  
Deposition Density ◽  
Frost Layer

An experimental study has been conducted to investigate the effects of surface energy on frost formation. Test samples with three different surfaces of which dynamic contact angles (DCA) were 23, 55, and 88 deg were installed in a wind tunnel and exposed to a humid airflow. The airflow Reynolds number, humidity, the air and the cold plate temperatures were maintained at 9000, 0.0042 kg/kg′, +12 and −22°C, respectively. The thickness and the mass of frost layer were measured and used to calculate frost density while heat flux and temperature profile were measured to obtain thermal conductivity. Exact positions of thermocouple junctions were verified by means of visualization system in order to increase accuracy. Results showed that frost density and thermal conductivity increase with time. The surface with a lower DCA showed a higher frost density and thermal conductivity during a two-hour test, but minor differences have been found after two hours of frost generation. Empirical correlations for thickness, mass deposition, density and thermal conductivity were proposed as the functions of test time and surface energy.

Frost Formation and its Density Behavior on Various Surfaces

2001 ◽  
Author(s):  
Cheolhwan Kim ◽  
Jongmin Shin ◽  
Alexei V. Tikhonov ◽  
Samchul Ha ◽  
Bongjun Choi
Keyword(s):  
Surface Energy ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Test Time ◽  
Test Results ◽  
Plate Temperature ◽  
Specific Test ◽  
Frost Formation ◽  
Frost Layer ◽  
Density Behavior

Abstract An experimental study has been conducted to investigate the effects of surface energy on frost formation. Test samples with three different surfaces of which Dynamic Contact Angles (DCA) are 23, 55 and 88 degrees are installed in a wind tunnel and exposed to a humid airflow. The thickness and the mass of frost layer are measured and used to calculate frost density while frost formation is visualized simultaneously with their measurements. Results show that frost density increases as time increases at specific test conditions. The air Reynolds number, the airflow humidity and the cold plate temperature are maintained at 12,000, 0.0042 kg/kg and −20 degrees Celsius, respectively. The surface with a lower DCA shows a higher frost density for a two-hour test, but no differences in frost density have been found after two hours of frost generation. Empirical correlations for thickness, mass and density are proposed as the functions of test time and surface energy. Visualization of frost generation was in good agreements with test results.

Experimental study of dynamic contact angles on rough hydrophobic surfaces

2018 ◽  
Vol 513 ◽  
pp. 658-665 ◽  
Author(s):  
Alireza Mohammad Karim ◽  
Jonathan P. Rothstein ◽  
H. Pirouz Kavehpour
Keyword(s):  
Experimental Study ◽  
Dynamic Contact ◽  
Contact Angles ◽  
Hydrophobic Surfaces

scholarly journals An experimental study of the motion of ice past obstacles by the process of regelation

1976 ◽  
Vol 17 (75) ◽  
pp. 79-98 ◽  
Author(s):  
E. M. Morris
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Cross Sections ◽  
Transition Point ◽  
Water Layer ◽  
Single Object ◽  
Two Systems ◽  
Basal Sliding

AbstractThe results of regelation experiments, in which a single object is pulled through ice, cannot be applied directly to the problem of basal sliding in glaciers because the two systems have different geometries. When the force applied to a single object is small, impurities trapped in the regelation water-layer around the object inhibit the regelation process. At larger forces, above the Drake-Shreve transition point, impurities are shed in a trace behind the object. However, when ice moves over a series of obstacles a trace may exist above and below the transition point. The regelation velocity below the transition point is not reduced by the effect of trapped impurities. In an experiment in which brass cylingerrs of various cross-sections rotate in ice, the ratio between the expected regelation velocity, calculated using the basal-sliding theory of Nye, and the measured regelation velocity is 8±2, both above and below the transition point. The same ratio has been obtained by other workers with wires of similar thermal conductivity above the transition point. Measurements of température differences indicate that supercooling cannot be the main source of the unexpectedly low regelation velocities above the transition point.

scholarly journals Study on contact angles and surface energy of MXene films

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5512-5520
Author(s):  
Hang Zhou ◽  
Fuqiang Wang ◽  
Yuwei Wang ◽  
Changping Li ◽  
Changrui Shi ◽  
...  
Keyword(s):  
Surface Energy ◽  
Contact Angles ◽  
Time Dependent ◽  
Wetting Behaviors

This work sheds light on the process- and time-dependent wetting behaviors and surface energy of MXene films.

A novel method for measuring dynamic contact angles of fibers with spindle‐knots

2021 ◽  
Vol 138 (28) ◽  
Author(s):  
Maryam Aliabadi ◽  
Wilfried Konrad ◽  
Thomas Stegmaier ◽  
Volkmar Arnim ◽  
Cigdem Kaya ◽  
...  
Keyword(s):  
Dynamic Contact ◽  
Contact Angles ◽  
Novel Method
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