Real-time direct measurement of liquid (water) evaporation by simple disturbance inhibited interfometry technique

2017 ◽  
Vol 71 (9) ◽  
pp. 554-560
Author(s):  
Yong Gi Kim
Keyword(s):  
Real Time ◽  
Direct Measurement ◽  
Liquid Water ◽  
Water Evaporation

scholarly journals Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2967
Author(s):  
Adrian Mularczyk ◽  
Andreas Michalski ◽  
Michael Striednig ◽  
Robert Herrendörfer ◽  
Thomas J. Schmidt ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Liquid Water ◽  
Evaporative Cooling ◽  
Gas Diffusion ◽  
Polymer Electrolyte Fuel Cell ◽  
Ex Situ ◽  
Water Evaporation ◽  
Evaporative Water ◽  
Gas Diffusion Layers ◽  
Diffusion Layers

Facilitating the proper handling of water is one of the main challenges to overcome when trying to improve fuel cell performance. Specifically, enhanced removal of liquid water from the porous gas diffusion layers (GDLs) holds a lot of potential, but has proven to be non-trivial. A main contributor to this removal process is the gaseous transport of water following evaporation inside the GDL or catalyst layer domain. Vapor transport is desired over liquid removal, as the liquid water takes up pore space otherwise available for reactant gas supply to the catalytically active sites and opens up the possibility to remove the waste heat of the cell by evaporative cooling concepts. To better understand evaporative water removal from fuel cells and facilitate the evaporative cooling concept developed at the Paul Scherrer Institute, the effect of gas speed (0.5–10 m/s), temperature (30–60 °C), and evaporation domain (0.8–10 mm) on the evaporation rate of water from a GDL (TGP-H-120, 10 wt% PTFE) has been investigated using an ex situ approach, combined with X-ray tomographic microscopy. An along-the-channel model showed good agreement with the measured values and was used to extrapolate the differential approach to larger domains and to investigate parameter variations that were not covered experimentally.

Real-Time and Direct Measurement of Pollutants in Exhaust Gas Utilizing Supersonic Jet / Resonance Enhanced Multi-Photon Ionization

2008 ◽  
Author(s):  
Kentaro Misawa ◽  
Jun Matsumoto ◽  
Yohei Yamato ◽  
Saori Mae ◽  
Shun-ichi Ishiuchi ◽  
...  
Keyword(s):  
Real Time ◽  
Direct Measurement ◽  
Supersonic Jet ◽  
Exhaust Gas ◽  
Photon Ionization

Femtosecond Dynamics of Hydrogen Bonds in Liquid Water: A Real Time Study

2000 ◽  
Vol 47 (4A) ◽  
pp. 685-692 ◽  
Author(s):  
Noelle Lascoux ◽  
Guilhem Gallot ◽  
Francois Hache ◽  
Geoffrey Mitchell Gale ◽  
Savo Bratos ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Real Time ◽  
Liquid Water ◽  
Time Study ◽  
Femtosecond Dynamics

scholarly journals A New Conceptual Model for Adiabatic Fog

2021 ◽  
Author(s):  
Felipe Toledo ◽  
Martial Haeffelin ◽  
Eivind Wærsted ◽  
Jean-Charles Dupont
Keyword(s):  
Life Cycle ◽  
Conceptual Model ◽  
Real Time ◽  
Liquid Water ◽  
Critical Value ◽  
Liquid Water Path ◽  
Horizontal Visibility ◽  
Fog Water ◽  
Water Path ◽  
The Way

Abstract. We propose a new paradigm to describe the temporal evolution of continental fog layers. This paradigm defines fog as a layer saturated from the surface to a known upper boundary, and whose liquid water path (LWP) exceeds a critical value, the critical liquid water path (CLWP). When the LWP is less than the CLWP the fog water cannot extend all the way to the surface, leading to a surface horizontal visibility greater than 1 km. On the opposite, when the LWP is larger than the CLWP, the fog water extends all the way to the surface, inducing a horizontal visibility less than 1 km. The excess water with respect to the critical value is then defined as the reservoir liquid water path (RLWP). The new fog paradigm is formulated as a conceptual model that relates the liquid water path of adiabatic fog with its thickness and surface liquid water content, and allows the critical and reservoir liquid water paths to be computed. Both variables can be tracked in real time using vertical profiling measurements, enabling a real time diagnostic of fog status. The conceptual model is tested using data from seven years of measurements performed at the SIRTA observatory, combining cloud radar, microwave radiometer, ceilometer, scatterometer and weather station measurements. In this time period we found 80 fog events with reliable measurements, with 56 of these lasting more than three hours. The paper presents the conceptual model and its capability to derive the LWP from the fog CTH and surface horizontal visibility with an RMS uncertainty of 10.5 g m−2. The impact of fog liquid water path and fog top height variations on fog life cycle (formation to dissipation) is presented based on four case studies, and statistics derived from 56 fog events. Our results show in particular that the reservoir liquid water path is consistently positive during the mature phase of the fog and that it starts to decrease quasi monotonously about one hour before dissipation, reaching a near-zero value at the time of dissipation. The reservoir liquid water path and its time derivative could hence be used as an indicator for life cycle stage and support short range forecasting of fog dissipation.

Simulation of Liquid Water Evaporation in GDL for PEMFC Under Gas Purge Condition

2011 ◽  
Author(s):  
Gen Inoue ◽  
Naoyuki Ishibe ◽  
Yosuke Matsukuma ◽  
Masaki Minemoto
Keyword(s):  
Porous Structure ◽  
Network Model ◽  
Liquid Water ◽  
Gas Diffusion ◽  
Water Evaporation ◽  
Uniform Structure ◽  
Interface Area ◽  
Two Phase ◽  
Actual Structure ◽  
Gas Purge

In automotive Polymer Electrolyte Fuel Cell (PEFC) system, dry gas purge operation is needed at shutdown condition in order to remove the liquid water in gas diffusion layer (GDL) and to reduce the oxygen diffusion inhibition by liquid water in GDL. However, exceed drying operation leads to degradation of electrolyte membrane because of little water content. Therefore, drying process has to be optimized. In this study, various GDL structure with unique fiber orientation were simulated by numerical analysis, and the real GDL structure was reconstructed by X-ray CT image of carbon paper GDL. Next, our past two-phase network model was improved to include phase change effect. The multi-block two-phase network model based on an actual structure was developed by a direct 3D networking porous structure. As results, the evaporation interface area depended on the porous structure of GDL, and the overall evaporation rate of homogeneous GDL which has uniform structure was 1.5 time higher than that of heterogeneous GDL because of the difference of this interface area. In addition, in the case of rib and channel, liquid water under channel evaporated faster than that under Rib. It is very important to control the drying operation in order to prevent the excess membrane drying.

Direct Measurement of Refraction Spectrum of Liquid Water at Submillimetre Wavelengths

1973 ◽  
Vol 243 (129) ◽  
pp. 116-117 ◽  
Author(s):  
JOHN CHAMBERLAIN ◽  
M. S. ZAFAR ◽  
J. B. HASTED
Keyword(s):  
Direct Measurement ◽  
Liquid Water

Real-time direct measurement of spinal cord blood flow at the point of compression

2009 ◽  
Vol 65 ◽  
pp. S125
Author(s):  
Tadao Morino ◽  
Tadanori Ogata ◽  
Kei Morizane ◽  
Gotaro Yamaoka ◽  
Haruyasu Yamamoto
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Real Time ◽  
Direct Measurement ◽  
Spinal Cord Blood Flow
Sign in / Sign up

Export Citation Format

Share Document