Flow Visualization and Stream Temperature Measurement of Liquid Hydrogen Line Chill Down Experiments

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Jeremy Styborski
Keyword(s):  
Temperature Measurement ◽  
High Speed ◽  
Hydrogen Transfer ◽  
Imaging System ◽  
Bubbly Flow ◽  
Stream Temperature ◽  
Liquid Hydrogen ◽  
Low Earth Orbit ◽  
High Speed Imaging ◽  
Transfer Line

A thermally representative tank-to-tank transfer line was designed and tested at SMiRF at NASA Glenn to simulate liquid hydrogen transfer from a Low Earth Orbit depot storage tank to a customer receiver tank. The line was equipped with three external skin silicon diode measurements, one internal stream temperature measurement, and a high speed imaging system to view flow profiles as the system chilled down from 250K to LH2 temperatures. Image: Two phase flow video stills correlated with temperature measurements shows the time evolution of chill down. Skin measurements indicate chill down is nearly complete within 20s due to annular flow and liquid layer along wall, but internal stream temperature doesn't bottom out until >140s due to bubbly flow. Majority of chill down is spent in annular and bubbly flow regimes. SD1-3 are successive skin diodes mounted along the transfer line.

Bubble Size Reduction Using Mesh Bubble Breakers in Two-Phase Vertical Co-Flow

2015 ◽  
Author(s):  
Alan Kalbfleisch ◽  
Kamran Siddiqui
Keyword(s):  
Pore Size ◽  
Bubble Size ◽  
Slug Flow ◽  
High Speed ◽  
Imaging System ◽  
Bubbly Flow ◽  
High Speed Imaging ◽  
Two Phase ◽  
Vertical Column ◽  
Experimental Apparatus

Bubble breakers have been shown to reduce the bubble size and hence increasing the bubble surface-to-volume ratio facilitating higher mass transfer. We report on an experimental study investigating the effect of mesh-type bubble breaker on two-phase co-flow in a vertical column. A range of gas-liquid flow rates ratios (GLR) has been considered that covers the two-phase regimes from bubbly flow to slug flow. A vertical glass tube was used as the experimental apparatus which provides full optical access. A high speed imaging system was used to capture the flow dynamics for bubble characterization. The results show that the bubble size generated by the mesh bubble breaker is greatly affected by the pore size. For a bubbly flow regime, the initial bubble size was reduced by approximately 60%–70% for a pore size of 1mm and by about 45%–50% for a pore size of 4mm. It is found that the transition from bubbly flow to slug flow can be affected by the mesh bubble breaker. The results show that in general, the mesh bubble breaker increases the GLR limit for the transition from bubbly to slug flow.

scholarly journals Experimental study of the dynamic behaviour of High Performance Concrete (HPC) under tensile loading

2018 ◽  
Vol 183 ◽  
pp. 02043 ◽  
Author(s):  
Bratislav Lukić ◽  
Dominique Saletti ◽  
Pascal Forquin
Keyword(s):  
High Speed ◽  
High Performance ◽  
High Performance Concrete ◽  
Imaging System ◽  
Spall Strength ◽  
High Speed Imaging ◽  
Dynamic Tensile Strength ◽  
Full Field ◽  
Local Point ◽  
Measurement Results

This paper presents the measurement results of the dynamic tensile strength of a High Performance Concrete (HPC) obtained using full-field identification method. An ultra-high speed imaging system and the virtual fields method were used to obtain this information. Furthermore the measurement results were compared with the local point-wise measurement to validate the data pressing. The obtained spall strength was found to be consistently 20% lower than the one obtained when the Novikov formula is used.

Nucleate Boiling From Micro-Machined Surfaces

2003 ◽  
Author(s):  
Adrian M. Holland ◽  
Colin P. Garner
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Imaging System ◽  
Laser System ◽  
Ccd Camera ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Frame Rate ◽  
High Speed Imaging ◽  
Machined Surfaces

This paper discusses the production and use of laser-machined surfaces that provide enhanced nucleate boiling and heat transfer characteristics. The surface features of heated plates are known to have a significant effect on nucleate boiling heat transfer and bubble growth dynamics. Nucleate boiling starts from discrete bubbles that form on surface imperfections, such as cavities or scratches. The gas or vapours trapped in these imperfections serve as nuclei for the bubbles. After inception, the bubbles grow to a certain size and depart from the surface. In this work, special heated surfaces were manufactured by laser machining cavities into polished aluminium plates. This was accomplished with a Nd:YAG laser system, which allowed drilling of cavities of a known diameter. The size range of cavities was 20 to 250 micrometers. The resulting nucleate pool boiling was analysed using a novel high-speed imaging system comprising an infrared laser and high resolution CCD camera. This system was operated up to a 2 kHz frame rate and digital image processing allowed bubbles to be analysed statistically in terms of departure diameter, departure frequency, growth rate, shape and velocity. Data was obtained for heat fluxes up to 60 kW.m−2. Bubble measurements were obtained working with water at atmospheric pressure. The surface cavity diameters were selected to control the temperature at which vapour bubbles started to grow on the surface. The selected size and spacing of the cavities was also explored to provide optimal heat transfer.

scholarly journals Low-Cost High-Speed Imaging System for Observing Vocal Fold Vibration in Voice Disorders

ORL ◽  
2012 ◽  
Vol 74 (4) ◽  
pp. 208-210 ◽  
Author(s):  
Kenichi Kaneko ◽  
Koichi Sakaguchi ◽  
Masato Inoue ◽  
Haruo Takahashi
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Imaging System ◽  
Low Cost ◽  
Voice Disorders ◽  
High Speed Imaging ◽  
Vocal Fold Vibration

Velocity Measurements Using High-Speed Imaging System for Impact Test

2014 ◽  
Vol 903 ◽  
pp. 187-193 ◽  
Author(s):  
Abdul Aziz Jaafar ◽  
Anwar P.P. Abdul Majeed ◽  
S.M. Sapuan ◽  
Shahnor Basri
Keyword(s):  
High Speed ◽  
Impact Test ◽  
Imaging System ◽  
Velocity Measurements ◽  
Glass Composite ◽  
Free Flight ◽  
High Speed Imaging ◽  
Fibre Glass ◽  
System A ◽  
Kinematic Properties

This paper presents the velocity measurements for an impact test on a laminated fibre-glass composite plate. The free flight kinematic properties of a blunt-nosed cylindrical projectile on the upstream and downstream of a test coupon were measured using a high-speed camera imaging system. A visual geometric detection technique is discussed and it is shown that the uncertainties of velocity measurements are associated with an imposed constraint on the camera viewing area and shutter speed.

Visualization of Oil Droplets Distribution in a Rotary Compressor

2019 ◽  
Author(s):  
Puyuan Wu ◽  
Jun Chen ◽  
Paul E. Sojka
Keyword(s):  
Multiphase Flow ◽  
High Speed ◽  
Imaging System ◽  
Discharge Rate ◽  
Current Phase ◽  
Rotary Compressor ◽  
Cfd Analysis ◽  
High Speed Imaging ◽  
Oil Droplets ◽  
Rolling Piston

Abstract A rotary compressor relies on an eccentric rolling piston, which rotates at high speed, to compress gas in the compression chamber. The oil in the rotary compressor is used for lubricating the bearing and sealing the clearance of sliding parts. However, the oil can exhaust from the rotary compressor by the refrigerant flow and reduce the reliability of the compressor as a result. Thus, studying the behavior of oil droplets distribution in a rotary compressor is a major challenge for manufacturers who rely on CFD tools to predict the multiphase flow. By modifying a rotary compressor, the oil behavior inside the cylinder is observed and recorded by a high-speed imaging system. In the current phase, multiple targeted locations, including the space between the bearing housing and the stator, and the space above the stator are measured in different conditions. The number, size, velocity, and morphology of oil droplets are analyzed based on multiple snapshots. The result can assist designers in improving the CFD analysis of compressors and ultimately reducing the oil discharge rate (ODR).

A visible light high-speed imaging system and tomographic reconstruction of plasma emissivity on the J-TEXT tokamak

2019 ◽  
Vol 146 ◽  
pp. 578-581
Author(s):  
Minghui Xia ◽  
Zhipeng Chen ◽  
Huapu Deng ◽  
Jie Yang ◽  
Lizhi Zhu ◽  
...  
Keyword(s):  
Visible Light ◽  
High Speed ◽  
Imaging System ◽  
Tomographic Reconstruction ◽  
High Speed Imaging
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