The transitions of time-independent spreading diameter and splashing angle when a droplet train impinging onto a hot surface

RSC Advances ◽  
2016 ◽  
Vol 6 (17) ◽  
pp. 13644-13652 ◽  
Author(s):  
Lu Qiu ◽  
Swapnil Dubey ◽  
Fook Hoong Choo ◽  
Fei Duan
Keyword(s):  
High Temperature ◽  
Water Droplet ◽  
High Speed ◽  
High Speed Camera ◽  
Hot Surface

The hydrodynamic patterns of the impingement of a water droplet train on a high temperature substrate are captured with a high-speed camera, and then analyzed.

scholarly journals Pinned Droplet Size on a Superhydrophobic Surface in Shear Flow

Aerospace ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 34
Author(s):  
Mitsugu Hasegawa ◽  
Katsuaki Morita ◽  
Hirotaka Sakaue ◽  
Shigeo Kimura
Keyword(s):  
Boundary Layer ◽  
Shear Flow ◽  
Droplet Size ◽  
Water Droplet ◽  
Superhydrophobic Surface ◽  
High Speed ◽  
High Speed Camera ◽  
Sessile Droplet ◽  
Air Velocity

The recent development of a superhydrophobic surface enhances the droplet shedding under a shear flow. The present study gives insights into the effects of shear flow on a pinned droplet over a superhydrophobic surface. To experimentally simulate the change in the size of a sessile droplet on an aerodynamic surface, the volume of the pinned droplet is expanded by water supplied through a pore. Under a continuous airflow that provides a shear flow over the superhydrophobic surface, the size of a pinned water droplet shed from the surface is experimentally characterized. The air velocity ranges from 8 to 61 m/s, and the size of pinned droplets shed at a given air velocity is measured using an instantaneous snapshot captured with a high-speed camera. It is found that the size of the shedding pinned droplet decreases as air velocity increases. At higher air velocities, shedding pinned droplets are fully immersed in the boundary layer. The present findings give a correlation between critical air velocity and the size of pinned droplets shed from the pore over the superhydrophobic surface.

Dynamic Behavior of a Small Water Droplet Impact Onto a Heated Hydrophilic Surface

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
El-Sayed R. Negeed ◽  
M. Albeirutty ◽  
Sharaf F. AL-Sharif ◽  
S. Hidaka ◽  
Y. Takata
Keyword(s):  
Dynamic Behavior ◽  
Water Droplet ◽  
High Speed ◽  
Heated Surface ◽  
Droplet Diameter ◽  
Video Camera ◽  
Surface Wettability ◽  
Hydrodynamic Characteristics ◽  
Small Water ◽  
Hot Surface

The aim of this study is to investigate the influence of the surface wettability on the dynamic behavior of a water droplet impacting onto a heated surface made of stainless steel grade 304 (Sus304). The surface wettability is controlled by exposing the surfaces to plasma irradiation for different time periods (namely, 0.0, 10, 60, and 120 s). The experimental runs were carried out by spraying water droplets on the heated surface where the droplet diameter and velocity were independently controlled. The droplet behavior during the collision with the hot surface has been recorded with a high-speed video camera. By analyzing the experimental results, the effects of surface wettability, contact angle between impacting droplet and the hot surface, droplet velocity, droplet size, and surface superheat on the dynamic behavior of the water droplet impacting on the hot surface were investigated. Empirical correlations are presented describing the hydrodynamic characteristics of an individual droplet impinging onto the heated hydrophilic surfaces and concealing the affecting parameters in such process.

Investigation of Single Water Droplet Evaporation over Aluminium Surfaces Using High Speed Camera and Image Processing

2014 ◽  
Vol 592-594 ◽  
pp. 1642-1646
Author(s):  
V. Harshavardhan Reddy ◽  
Shaik Sadiq ◽  
S. Arunkumar ◽  
M. Venkatesan
Keyword(s):  
Image Processing ◽  
Surface Temperature ◽  
Water Droplet ◽  
High Speed ◽  
Image Processing Technique ◽  
High Speed Camera ◽  
Water Droplets ◽  
Online Data ◽  
Plate Temperature ◽  
Cooling Effects

The study of evaporation of water droplets over horizontal heated surfaces is an intense area of research because of its wide application in various fields of heat transfer. The characterization of the behavior of water droplets is important in studying the cooling effects produced over impinging surfaces. The present study focuses on analyzing the shape and size of the droplets by applying image processing techniques. In the present work, a fixed volume of single water droplet is made to impinge on a horizontal Aluminium surface using a designed microcontroller based syringe pump. The formation and the dynamics of bubbles are recorded using a high speed camera. Image processing technique is used to determine the droplet parameters such as contact angle, spreading radius and to study the shape of the droplet. The surface temperature is measured using a Thermocouple connected to an online Data acquisition system. The effect of the characteristics of droplet on the decrease in surface temperature can be seen from the temperature – time graph and the processed photographs taken using high speed camera. The decrease in base plate temperature is found to be depending on the behavior and the properties of the droplet.

Visual Experiments on the Subcooled Water Droplet Behavior in High Temperature Molten Metal

2012 ◽  
Author(s):  
Yuan Zhou ◽  
Meng Lin ◽  
Zhengming Zhang ◽  
Lei Lei
Keyword(s):  
High Temperature ◽  
Water Droplet ◽  
High Speed ◽  
Water Injection ◽  
Spherical Shape ◽  
Video Camera ◽  
Liquid Pool ◽  
Vapor Film ◽  
High Speed Video Camera ◽  
Droplet Behavior

Water injection mode of molten fuel/coolant interaction is a key issue during the steam generator tube rupture in liquid metal reactors. The fragmentation behaviors of plunging water droplet into a high temperature molten tin liquid pool were studied by using a high speed video camera. Photographs of the water droplet configuration, the vaporization at the interface between the melt and water, and the vapor film disturbance were obtained. The results demonstrated that the water droplet in the molten tin pool was near spherical shape initially and the vapor was generated and accumulated in the bottom of the water droplet. The steam explosions happened when vapor film collapses finally.

ALX ALLOY

Alloy Digest ◽  
1963 ◽  
Vol 12 (1) ◽  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Speed ◽  
Heat Treating ◽  
Temperature Performance ◽  
Cobalt Base

Abstract ALX is a composition of nonferrous materials with a cobalt base containing chromium, tungsten and carbon. This alloy is commonly supplied in the cast-to-shape form, having an as-cast hardness of Rockwell C60-62 and requiring no further heat treatment. ALX is also supplied as cast tool bit material and is useful where conventional high-speed steels or carbides do not function effectively. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, forming, heat treating, and machining. Filing Code: Co-35. Producer or source: Allegheny Ludlum Corporation.

CYCLOPS M4

Alloy Digest ◽  
1978 ◽  
Vol 27 (7) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Abrasion Resistance ◽  
High Speed ◽  
Heat Treating ◽  
Heavy Duty ◽  
Maximum Hardness ◽  
Temperature Performance ◽  
Sharp Edges ◽  
Normal Carbon

Abstract CYCLOPS M4 is a deep-hardening steel that was developed to utilize the excellent abrasion resistance that results from higher-than-normal carbon and vanadium contents in the molybdenum-tungsten family of high-speed steels. It is recommended for heavy-duty cutting operations and for sharp edges for fine cuts. Cyclops M4 should always be used at or near maximum hardness. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-335. Producer or source: Cyclops Corporation.

CRUCIBLE CPM REX 121

Alloy Digest ◽  
2001 ◽  
Vol 50 (10) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
High Temperature ◽  
High Speed ◽  
High Speed Steel ◽  
Heat Treating ◽  
Maximum Hardness ◽  
Temperature Performance ◽  
Red Hardness ◽  
Cutting Speeds

Abstract CPM Rex 121 is a super high-speed steel with significantly higher wear resistance and red hardness than other high-speed steels. It is best suited for applications requiring high cutting speeds. It may provide an alternative to carbide where carbide cutting edges are too fragile. The annealed hardness is approximately 350-400 HB, and maximum hardness is approximately 72 HRC. This datasheet provides information on composition, physical properties, microstructure, hardness, and elasticity as well as fracture toughness. It also includes information on high temperature performance and wear resistance as well as heat treating and surface treatment. Filing Code: TS-591. Producer or source: Crucible.

YSS YXM4

Alloy Digest ◽  
2019 ◽  
Vol 68 (11) ◽  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Physical Properties ◽  
Tool Steel ◽  
High Speed ◽  
Temperature Performance

Abstract YSS YXM4 is a cobalt-alloyed molybdenum high-speed tool steel with resistance to abrasion, seizure, and deformation under high pressure. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance. Filing Code: TS-780. Producer or source: Hitachi Metals America, Ltd.

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