Air Flow and Liquid Water Concentration Simulations of the 2012 NASA Glenn Icing Research Tunnel

2012 ◽  
Author(s):  
Kevin Clark ◽  
Michael Malinowski ◽  
Eric Loth ◽  
Judith Van Zante ◽  
Laura-Cheri Steen ◽  
...  
Keyword(s):  
Liquid Water ◽  
Air Flow ◽  
Water Concentration

Separation and Hydrodynamic Performance of Air-Kerosene-Water System by Bubble Column

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Abbas H. Sulaymon ◽  
Ahmed Abed Mohammed
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Bubble Column ◽  
Removal Rate ◽  
Air Flow ◽  
Bubble Diameter ◽  
Water Concentration ◽  
Hydrodynamic Performance ◽  
Air Flow Rate ◽  
Flotation Process

The separation of emulsified kerosene in water (concentration 250-750ppm) was investigated in a bubble column15.6 cm diameter and 120 cm height. The effective behaviors of bubble characteristics (bubble diameter, bubble rise velocity and air hold-up) on the removal efficiency were measured by electroresistivity probe. The effects of kerosene concentration, air flow rate,bubble diameter, liquid height, liquid viscosity, NaCl concentration, and alum on the removal rate were found. The experimental results showed that the removal efficiency increased with increasing air flow rate (1.09-2.6cm/s) and decreased with increasing CMC concentration. The results also showed that adding anionic surfactants (SLES and SDBS) leads to increase removal rate. The the flotation process was found to be first order kinetics. New correlations of air holdup and bubble diameter using dimensionless groups were derived.

Modeling of Flooding Phenomena in Hydrophobic Gas Diffusion Layer of PEFC

2007 ◽  
Author(s):  
Kazuhiko Kudo ◽  
Akiyoshi Kuroda ◽  
Shougo Takeoka ◽  
Yosuke Shimazu
Keyword(s):  
Diffusion Layer ◽  
Liquid Water ◽  
Air Flow ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Flow Channel ◽  
Cathode Side ◽  
Model Following ◽  
Condensed Water ◽  
Different Diameters

The mechanism of liquid water removal, water vapor diffusion and oxygen diffusion in cathode side gas diffusion layer (GDL) of PEFC is studied by modeling the GDL as a hydrophobic flat plate with many straight holes with different diameters. As the results of the consideration using the model, following results are obtained. The spots where liquid water condensation is taken place between GDL-MEA gap are limited to the inlets of holes with larger diameters, and the condensed water is drained to air flow channel only through the larger holes. Other holes with smaller diameters are free of liquid water, and oxygen diffuses from the air flow channel to the catalyst surface through such holes. The reduction of output voltage of fuel cell due to the increase in the current density may be caused by the reduction of the oxygen concentration in GDL-MEA gap. The condensate tends to penetrate into larger holes instead of filling the gap of GDL and MEA.

scholarly journals Water isotopic ratios from a continuously melted ice core sample

2011 ◽  
Vol 4 (11) ◽  
pp. 2531-2542 ◽  
Author(s):  
V. Gkinis ◽  
T. J. Popp ◽  
T. Blunier ◽  
M. Bigler ◽  
S. Schüpbach ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Water ◽  
Ice Core ◽  
Flow Analysis ◽  
Water Concentration ◽  
Isotopic Analysis ◽  
Fused Silica ◽  
Chemical Components ◽  
Smoothing Effects ◽  
Δ18o And Δd

Abstract. A new technique for on-line high resolution isotopic analysis of liquid water, tailored for ice core studies is presented. We built an interface between a Wavelength Scanned Cavity Ring Down Spectrometer (WS-CRDS) purchased from Picarro Inc. and a Continuous Flow Analysis (CFA) system. The system offers the possibility to perform simultaneuous water isotopic analysis of δ18O and δD on a continuous stream of liquid water as generated from a continuously melted ice rod. Injection of sub μl amounts of liquid water is achieved by pumping sample through a fused silica capillary and instantaneously vaporizing it with 100% efficiency in a~home made oven at a temperature of 170 °C. A calibration procedure allows for proper reporting of the data on the VSMOW–SLAP scale. We apply the necessary corrections based on the assessed performance of the system regarding instrumental drifts and dependance on the water concentration in the optical cavity. The melt rates are monitored in order to assign a depth scale to the measured isotopic profiles. Application of spectral methods yields the combined uncertainty of the system at below 0.1‰ and 0.5‰ for δ18O and δD, respectively. This performance is comparable to that achieved with mass spectrometry. Dispersion of the sample in the transfer lines limits the temporal resolution of the technique. In this work we investigate and assess these dispersion effects. By using an optimal filtering method we show how the measured profiles can be corrected for the smoothing effects resulting from the sample dispersion. Considering the significant advantages the technique offers, i.e. simultaneuous measurement of δ18O and δD, potentially in combination with chemical components that are traditionally measured on CFA systems, notable reduction on analysis time and power consumption, we consider it as an alternative to traditional isotope ratio mass spectrometry with the possibility to be deployed for field ice core studies. We present data acquired in the field during the 2010 season as part of the NEEM deep ice core drilling project in North Greenland.

Numerical Simulation of Liquid Water and Air Flow in Separator-Channels in PEM Fuel Cell Using LBM

2007 ◽  
Author(s):  
Yutaka Tabe ◽  
Kohsuke Kibo ◽  
Kazushige Kikuta ◽  
Takemi Chikahisa ◽  
Masaya Kozakai
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Water Droplet ◽  
Polymer Electrolyte Membrane ◽  
Air Flow ◽  
Pem Fuel Cell ◽  
Two Phase ◽  
Cross Sectional ◽  
Electrolyte Membrane ◽  
Condensed Water

In a polymer electrolyte membrane (PEM) fuel cell, the condensed water in the separator-channel prevents the supply of reactants to electrodes, which deteriorates the cell performance. The Lattice Boltzmann simulation has been developed to understand the behavior of condensed water in the separator-channels. The calculation process was improved, and the effect on the stability and reliability of simulation of two-phase flows with large density difference was confirmed. Further, the comparison with experiment of the falling water droplet by gravitation on the slope of micro porous layer was conducted to validate effectiveness of the improved simulation. It was shown that the simulation can express the increase in falling speed of water droplet and the effect of inclined angle of the slope, and our simulation is effective enough to estimate the liquid water and air flow in the separator-channel. Finally, the simulation of liquid water behaviors in separator-channels with various cross-sectional shapes was conducted, and the drain efficiency of water droplet of separator-channel was discussed.

The importance of liquid water concentration in the atmospheric oxidation of SO2

1987 ◽  
Vol 21 (11) ◽  
pp. 2333-2344 ◽  
Author(s):  
D. Lamb ◽  
D.F. Miller ◽  
N.F. Robinson ◽  
A.W. Gertler
Keyword(s):  
Liquid Water ◽  
Water Concentration ◽  
Atmospheric Oxidation

Unidirectional Air Flow Isolators A Review

1974 ◽  
Vol 30 (1) ◽  
pp. 32-41 ◽  
Author(s):  
E. J. Butler ◽  
B. J. Egan
Keyword(s):  
Air Flow
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