Study of Subcooled Film Boiling on a Horizontal Disc:1 Part 2—Experiments

2000 ◽  
Vol 123 (2) ◽  
pp. 285-293 ◽  
Author(s):  
D. Banerjee ◽  
V. K. Dhir
Keyword(s):  
Liquid Phase ◽  
Particle Tracking ◽  
Bubble Growth ◽  
High Speed ◽  
Particle Tracking Velocimetry ◽  
Digital Camera ◽  
Film Boiling ◽  
Convection Flow ◽  
Vapor Bubbles ◽  
Natural Convection Flow

Experiments were performed to study subcooled film boiling of performance liquid PF-5060 (made by 3-M Company) on a horizontal copper disc. The experiments were performed for two regimes of film boiling involving departing vapor bubbles (low subcooling) and nondeparting vapor bubbles (high subcooling). By employing high speed digital camera, data were obtained for temporal variation of bubble height, bubble shape and bubble growth rate over one cycle. Heat flux data were deduced from temperatures measured with thermocouples embedded in the solid. The results from the numerical model are compared with experimental data and are found to be in general agreement. Particle Tracking Velocimetry (PTV) experiments were performed for a configuration of non-departing vapor bubbles to study the flow field in the liquid phase. The PTV experiments point to the existence of natural convection flow in the liquid phase and is in qualitative agreement with the predictions available in the literature.

Study on high speed parallel algorithm using PC grid environment for visualization measurements by Digital Holographic Particle Tracking Velocimetry

2008 ◽  
Vol 178 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Shin-ichi Satake ◽  
Takafumi Anraku ◽  
Hiroyuki Kanamori ◽  
Tomoaki Kunugi ◽  
Kazuho Sato ◽  
...  
Keyword(s):  
Parallel Algorithm ◽  
Particle Tracking ◽  
High Speed ◽  
Particle Tracking Velocimetry ◽  
Grid Environment

scholarly journals Measurements of the Flow in the Vicinity of an Additively Manufactured Turbine Leading-Edge Using X-Ray Particle Tracking Velocimetry

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Alex Ruiz ◽  
Kamel Fezzaa ◽  
Jayanta Kapat ◽  
Samik Bhattacharya
Keyword(s):  
Velocity Field ◽  
Turbine Blade ◽  
Particle Tracking ◽  
High Speed ◽  
Particle Tracking Velocimetry ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Leading Edge ◽  
Inlet Channel ◽  
X Ray

Abstract X-ray particle tracking velocimetry (PTV) is performed, for the first time, to measure the velocity field inside a leading-edge of a turbine blade made by laser-additive-manufacturing (LAM) process. The traditional showerhead holes were replaced by a porous matrix in the leading-edge. The flow through such a leading-edge piece cannot be faithfully recreated by traditional prototype testing methods due to the surface roughness and imperfections caused by LAM process. Hence, direct measurement is the only option. However, it is difficult to measure flow inside such pieces with traditional velocimetry measurements due to the existence of metallic walls. Moreover, small internal size and high flow speeds call for a measurement technique with high spatial and temporal resolutions. To address these issues, we performed time-resolved X-ray PTV using the Advanced Photon Source (APS) synchrotron facility at the Argonne National Laboratory (ANL). A hydraulic system was constructed to run water, mixed with seeding particles, through the leading-edge piece. A high-speed camera captured the images of the seeding particles, which were later processed to create particle tracks. The time-averaged velocity field showed distinct pairs of vortices located in front of the porous outlet inside the leading-edge piece. The inlet channel showed reversed flow due to partial obstruction by the porous inlet of the test piece. Such knowledge of the flow field inside a leading-edge of a turbine blade will help us to design better cooling paths leading to higher cooling efficiency and increased life-span of a turbine blade.

Dynamics of Vapor Bubble Growth and Detachment in a Channel Flow

2006 ◽  
Author(s):  
G. Duhar ◽  
C. Colin
Keyword(s):  
Channel Flow ◽  
Bubble Growth ◽  
High Speed ◽  
Dominant Role ◽  
Bubble Radius ◽  
Video Camera ◽  
Vapor Bubbles ◽  
Equivalent Radius ◽  
Multiple Bubbles ◽  
Hot Film

The aim of this study is to improve the knowledge of the dynamics of vapor bubbles growing on a wall in a shear flow. Vapor bubbles are created on a hot film probe flushed mounted in the lower wall of a horizontal channel. The film overheat temperature controlled by an anemometer is limited to 20°C to avoid the growth of multiple bubbles. The liquid flow in the channel measured by Particle Image Velocimetry is laminar or turbulent. Bubble growth and detachment in the channel flow are filmed with a high-speed video camera at 2000 frame/second. Image processing allows obtaining the temporal evolutions of the bubble kinematics characteristics: the equivalent radius and the position of the centre of gravity. These data are then used to calculate the bubble growth rate and the forces acting on the bubbles during their growth and after their detachment. After detachment, drag, buoyancy and added mass forces play a dominant role. From the investigation of the bubble trajectories after detachment, the drag coefficient can be determined. When the bubble is attached to the wall capillary forces are dominant. A predictive model for bubble radius at detachment is provided depending on the wall overheat.

Boiling Investigation on a Surface With Artificial and Natural Nucleons Sites

2008 ◽  
Author(s):  
Yu. A. Kuzma-Kichta ◽  
A. Lavrikov ◽  
S. Afonin ◽  
M. Shustov
Keyword(s):  
Heat Flux ◽  
Video Processing ◽  
High Speed ◽  
Water Solution ◽  
Pool Boiling ◽  
Digital Camera ◽  
Vapor Bubbles ◽  
Artificial Cavity ◽  
Single Cavity ◽  
Engineering Institute

The water and Na2SO4 water solution boiling investigation had been carried in pool on the surfaces with artificial and natural nucleons sites under different pressures using high speed digital camera. The boiling of water was investigated at atmosphere pressure on a surface with a artificial nucleons site, which had a micro scale (cavity’s diameters – 100 and 200 μm and depth – 80 μm), in the Fridrich-Alexander University Erlangen-Nu¨rnberg, Germany in the Institute of Fluid Mechanics. The boiling of water and Na2SO4 water solution with concentration 20 g/l was investigated on a surface with natural nucleons sites in the pressure range 0.1 – 1 MPa in the Moscow Power-Engineering Institute (Technical University) on department of Thermal Physics. The “hand” video processing was used for the study’s results in case of the pool boiling on a surface with a artificial nucleon site. The data processing was realized for the study’s results using with a program “Bubble Detector”, which was specially developed for case of the pool boiling on a surface with the natural nucleon sites, and the “hand” processing was carried for video, which showed the reliability of the program “Bubble Detector”. First the distributions and dependences of basic boiling characteristics (frequency, departure diameter) were obtained at water pool boiling on a surface with a artificial cavity in the range of heat flux from 20 to 128 kW/m2 and the time dependence of vapor bubble’s grow. It was obtained, that departure diameters of vapor bubbles do not depend in case of boiling on a surface with a single cavity practically on heat flux. First the distributions and dependences of swimming velocities and equivalent diameters were obtained at water and Na2SO4 water solution with concentration 20 g/l pool boiling on a surface with natural nucleon sites in range of pressures from 0.1 to 1 MPa. The comparison of diameters’ and swimming velocities’ distributions of vapor bubbles was carried for under consideration conditions.

scholarly journals Study on High Speed Parallel Algorithm Using PC for Visualization Measurements by Micro Digital Holographic Particle Tracking Velocimetry

2007 ◽  
Vol 73 (734) ◽  
pp. 2077-2084
Author(s):  
Shinichi SATAKE ◽  
Takafumi ANRAKU ◽  
Hiroyuki KANAMORI ◽  
Tomoaki KUNUGI ◽  
Kazuho SATO ◽  
...  
Keyword(s):  
Parallel Algorithm ◽  
Particle Tracking ◽  
High Speed ◽  
Particle Tracking Velocimetry

Three-Dimensional Particle Tracking Velocimetry With Laser-Light Sheet Scannings

1996 ◽  
Vol 118 (2) ◽  
pp. 352-357 ◽  
Author(s):  
Satoru Ushijima ◽  
Nobukazu Tanaka
Keyword(s):  
Particle Tracking ◽  
High Speed ◽  
Particle Tracking Velocimetry ◽  
Laser Light ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Light Sheet ◽  
Optical Scanners ◽  
Particle Images

This paper describes three-dimensional particle tracking velocimetry (3D PTV), which enables us to obtain remarkably larger number of velocity vectors than previous techniques. Instead of the usual stereoscopic image recordings, the present 3D PTV visualizes an entire three-dimensional flow with the scanning laser-light sheets generated from a pair of optical scanners and the images are taken by a high-speed video system synchronized with the scannings. The digital image analyses to derive velocity components are based on the numerical procedure (Ushijima and Tanaka, 1994), in which several improvements have been made on the extraction of particle images, the determination of their positions, the derivation of velocity components and others. The present 3D PTV was applied to the rotating fluids, accompanied by Ekman boundary layers, and their complicated secondary flow patterns, as well as the primary circulations, are quantitatively captured.

scholarly journals Errors in particle tracking velocimetry with high-speed cameras

2011 ◽  
Vol 82 (5) ◽  
pp. 053707 ◽  
Author(s):  
Yan Feng ◽  
J. Goree ◽  
Bin Liu
Keyword(s):  
Particle Tracking ◽  
High Speed ◽  
Particle Tracking Velocimetry

Research on Bubble Growth and Frequency at Higher System Pressure in Narrow Rectangular Channel

2013 ◽  
Author(s):  
Jian Hu ◽  
Puzhen Gao ◽  
Qiang Zheng
Keyword(s):  
Heat Flux ◽  
Mass Flux ◽  
Bubble Growth ◽  
High Speed ◽  
Rectangular Channel ◽  
Bubble Diameter ◽  
Digital Camera ◽  
Bubble Frequency ◽  
Heating Wall ◽  
System Pressure

In present work, the characteristics of bubble growth and frequency were visually observed in a narrow rectangular channel using high-speed digital camera. The experiment was done over the following range of conditions: pressure, 0.55MPa; mass flux, 300–500kg/(m2·s); heat flux, 86.4–225.7 kW/m2; and inlet subcooling, 25.5–45.5K. The system pressure has a significant effect on the bubble growth. Experimental results show that the bubble diameters are just about 0.15mm under higher system pressure and the period during which bubbles attaching to the nucleate site is very short, or even unnoticeable. The bubbles keep growing when slide along the heating wall rather than lifting off the surface, and the bubbles rarely collapse under the working conditions. When the mass flux is high, the bubble diameter increases with increasing the heat flux, but when the mass flux is low, the variation trend of bubble diameters expresses no obvious law. The effect of thermal parameters on bubble frequency is also significant. When the mass flux is low, the bubble frequency decreases with increasing the heat flux or inlet subcooling, however when the mass flux is high, the bubble frequency increases first and then decreases. Generally, the bubble frequency increases with increasing the mass flux.

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