Void Fraction and Pressure Drop in a Water Electrolysis Cell

1970 ◽  
Vol 92 (1) ◽  
pp. 173-182 ◽  
Author(s):  
J. F. Thorpe ◽  
J. E. Funk ◽  
T. Y. Bong
Keyword(s):  
Pressure Drop ◽  
Void Fraction ◽  
Water Electrolysis ◽  
Electrolysis Cell ◽  
Gas Generation ◽  
Slip Ratio ◽  
Frictional Pressure Drop ◽  
Electrolysis Cells ◽  
Gas Generation Rate ◽  
Data Reduction Technique

An experimental investigation was conducted to determine the void fraction and pressure drop occurring in a forced-convection water electrolysis cell. It was concluded that the slip ratio is essentially unity for water electrolysis cells operating at atmospheric pressure and 80–100 deg F. A frictional pressure-drop multiplier was determined by a data reduction technique that has been used extensively in the boiling heat transfer literature. This multiplier has been correlated and found to be a function of both the void fraction and the gas generation rate.

Two-Phase Flow Through Square and Circular Microchannels—Effects of Channel Geometry

2004 ◽  
Vol 126 (4) ◽  
pp. 546-552 ◽  
Author(s):  
Peter M.-Y. Chung ◽  
Masahiro Kawaji ◽  
Akimaro Kawahara ◽  
Yuichi Shibata
Keyword(s):  
Pressure Drop ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Separated Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Channel Geometry ◽  
Frictional Pressure Drop ◽  
Channel Shape

An adiabatic experiment was conducted to investigate the effect of channel geometry on gas-liquid two-phase flow characteristics in horizontal microchannels. A water-nitrogen gas mixture was pumped through a 96 μm square microchannel and the resulting flow pattern, void fraction and frictional pressure drop data were compared with those previously reported by the authors for a 100 μm circular microchannel. The pressure drop data were best estimated using a separated-flow model and the void fraction increased non-linearly with volumetric quality, regardless of the channel shape. However, the flow maps exhibited transition boundaries that were shifted depending on the channel shape.

Mathematical Modeling of De-Hydrogenation Micro-Reactors for Vehicles Using the Liquid Carrier of Hydrogen Fuel

2011 ◽  
Author(s):  
Mohamed E. Saleh ◽  
Wei Li ◽  
Shi-chune Yao
Keyword(s):  
Organic Liquid ◽  
Volume Ratio ◽  
Gas Generation ◽  
Two Phase ◽  
Slip Ratio ◽  
Pin Fin ◽  
Liquid Carrier ◽  
High Area ◽  
Gas Generation Rate ◽  
Micro Reactors

When the organic liquid carrier of hydrogen is used as the fuel on a vehicle, a key component is the hydrogen releasing device, which requires large surface area of catalyst, small size and light weight. Micro-reactors with internal structure of micro pin-fin array is considered due to its high area-to-volume ratio and intimate impaction-contact with the fluids. To support the design of a first experiment, a mathematical model based on laws of conservation and chemical reaction is established. A surface-reaction efficiency has also been included to consider the possible effect of surface nonwetting in the hydrogen two-phase flow. This model has been demonstrated using the N-Ethyl Carbazole as the liquid carrier and Palladium as the catalyst. Due to the large gas generation rate, the numerical modeling indicates that the system operates at high void fraction with large slip ratio. This leads to an alternative system design of using segmented reactors with a hydrogen separator located in between. This leads to reduced size of the system and less catalyst material used.

Experimental Investigation of the Effect of Surface Tension and the Correlation on Void Fraction and Frictional Pressure Drop of an Air-Liquid Two-Phase Flow in a Horizontal Flat Capillary Rectangular Channel

2003 ◽  
Author(s):  
Hideo Ide ◽  
Tohru Fukano
Keyword(s):  
Surface Tension ◽  
Pressure Drop ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Surfactant Solution ◽  
Phase Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Effect Of Surface

Air-liquid two-phase flow in a horizontal flat capillary rectangular channel has been studied to clarify the effects of concentration of surfactant solution on the flow phenomena, such as flow patterns, pressure drop, void fraction and so on. The concentrations of surfactant solution were 0, 10, 50 and 100 ppm and the surface tension of each solution was reduced to about 34mN/m from that of pure water of about 72mN/m. The dimension of the channel used was 10.0 mm × 1.0 mm. The drag reduction by mixing the surfactant was examined in both the single phase flow and the two-phase flow. The experimental data of two-phase frictional pressure drop and holdup were compared with the respective correlations which were previously proposed by the other researchers and the present authors. Finally, we proposed new correlations of two-phase frictional pressure drop and holdup in which the effect of surface tension and the aspect ratio of cross section of channel were taken into account.

Effect of Void Fraction on Pressure Drop in Upward Vertical Two-Phase Gas-Liquid Pipe Flow

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Clement C. Tang ◽  
Sanjib Tiwari ◽  
Afshin J. Ghajar
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Void Fraction ◽  
Gas Velocity ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Fraction Increase ◽  
Superficial Gas Velocity ◽  
Two Parameters

Experimental data for the void fraction and two-phase frictional pressure drop from various sources has been compiled and analyzed. The experimental data revealed that at the lower range of superficial gas velocity and void fraction, the variations of the two-phase frictional pressure drop with superficial gas velocity and void fraction are relatively flat. However, as the superficial gas velocity and void fraction increase to higher values, the frictional pressure drop became significantly sensitive to the two parameters. In a situation when the two-phase pressure drop is sensitive to the variation of the void fraction, it is then that the proper and accurate characterization of the void fraction becomes significant. From the experimental data, regions where the pressure drop is sensitive to the variation of the void fraction are identified and evaluated.

Experimental Study on the Effect of Surface Tension on Void Fraction and Frictional Pressure Drop of an Air-Liquid Two-Phase Flow in a Horizontal Flat Narrow Rectangular Channel

2003 ◽  
Author(s):  
Hideo Ide ◽  
Tohru Fukano
Keyword(s):  
Surface Tension ◽  
Pressure Drop ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Pure Water ◽  
Rectangular Channel ◽  
Phase Flow ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Effect Of Surface

Air-liquid two-phase flow in a horizontal flat capillary rectangular channel has been studied to clarify the effects of surface tension on the flow phenomena, such as flow patterns, holdup and frictional pressure drop and so on. The concentrations of surfactant solution were 0, 10, 50 and 100 ppm and the surface tension of each solution was reduced to about 34mN/m from that of pure water of about 72mN/m. The dimension of the channel used was 10.0 mm×1.0 mm. The drag reduction by mixing the surfactant was examined in both the single phase flow and the two-phase flow. The experimental data of void fraction and two-phase frictional pressure drop were compared with the respective correlations which were previously proposed by the other researchers. Finally, we proposed new correlations of two-phase frictional pressure drop in which the effect of surface tension and the aspect ratio of cross section of channel were taken into account.

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