Permeability and Porosity of Bonded Hollow Sphere Foams for High Intensity Radiant Burners

1994 ◽  
Vol 372 ◽  
Author(s):  
J. E. McEntyre ◽  
J. K. Cochran ◽  
K. J. Lee
Keyword(s):  
Hollow Sphere ◽  
High Intensity ◽  
Gas Flow ◽  
Point Contact ◽  
Operating Characteristics ◽  
Flow Through ◽  
Bonding Phase ◽  
Radiant Burners ◽  
The Relationship

AbstractBonded hollow sphere foams for this study were made from point-contact, slurry-bonded monosized spheres, 2.5 mm in diameter. The permeabilities of these foams are compatible with the diffuser base in radiant burners. For this study, the effect of quantity of bonding phase on interstitial porosity, permeability, and uniformity of gas flow through the foams was investigated. The relationship between permeability and porosity was modeled with the Kozeny-Carman equation. Attempts were made to correlate diffuser base permeability to operating characteristics of these burners.

The Relationship Between Breach Development and the Depressurization Transient During Axial Rupture of a Gas-Pressurized Steel Pipe

1982 ◽  
Vol 104 (1) ◽  
pp. 20-24 ◽  
Author(s):  
M. R. Baum
Keyword(s):  
Rarefaction Wave ◽  
Gas Flow ◽  
Theoretical Models ◽  
Observation Point ◽  
Steel Pipe ◽  
Growth Data ◽  
Flow Through ◽  
The Relationship ◽  
Experimental Pressure ◽  
Good Agreement

Theoretical models are developed to predict the depressurization generated by a propagating axial rupture in a gas-pressurized steel pipe. The pressure transient is composed of a relatively slow depressurization within the rarefaction wave which propagates through the undisturbed gas ahead of the developing breach and a rapid depressurization within the breach zone. The models combine a simplified one-dimensional treatment of the gas flow local to the breach with experimental breach area growth data. An instantaneous steady flow through the developing breach is assumed to determine the boundary condition for the rarefaction wave. The breach zone depressurization is assumed to be dominated by the transverse wave action initiated by the arrival of the breach at the observation point. In both cases the predicted transients are in good agreement with experimental pressure histories.

Pressure-flow behavior of a bronchopleural fistula during mechanical ventilation with positive pressure

1989 ◽  
Vol 66 (4) ◽  
pp. 1789-1799 ◽  
Author(s):  
J. J. Perez Fontan ◽  
A. O. Ray
Keyword(s):  
Gas Flow ◽  
Flow Behavior ◽  
Bronchopleural Fistula ◽  
Transmural Pressure ◽  
Positive Pressure ◽  
Inflation Pressure ◽  
Tracheal Pressure ◽  
Flow Through ◽  
The Difference ◽  
The Relationship

We examined the mechanical behavior of a bronchopleural fistula created by sectioning a small subpleural bronchus in seven anesthetized lambs. The pressure across the fistula was measured as the difference between the pressure recorded by a retrograde bronchial catheter inserted in the vicinity of the fistula and the outflow pressure at the fistula exit. The effective resistance of the fistula (Rf) was computed by dividing this pressure difference by the gas flow through the fistula measured at the outlet of an intrapleural tube adjacent to the fistula. Rf increased by 114 +/- 25% (SE) when we inflated the lungs in a stepwise manner from a tracheal pressure of 2–20 cmH2O. Rf also increased when inflation pressure varied continuously; this increase, however, was less evident when we decreased the inflation time from 1.0 to 0.2 s. The relationship between Rf and lung volume was similar during the stepwise inflations and deflations but showed marked hysteresis during the continuous inflation-deflation maneuvers, when Rf was greater during deflation than inflation. Our results suggest that the fistula behaves as a compliant pathway whose relevant transmural pressure is the transmural pressure at or near the fistula's exit. We attribute the increase in Rf during inflation to decreases in transmural pressure caused by convective and dissipative losses inside the fistula and by the stress applied by the chest wall on the outer surface of the fistula.

INVESTIGATION OF THE TIME OF GAS FLOW THROUGH A HOLE IN LONG PIPELINES UNDER HIGH PRESSURE

2020 ◽  
Vol 58 (1) ◽  
pp. 30-43
Author(s):  
N.D. Yakimov ◽  
◽  
A.I. Khafizova ◽  
N.D. Chichirova ◽  
O.S. Dmitrieva ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Flow ◽  
Flow Through

Free area for gas flow through sieve plates with a bubbled bed

1975 ◽  
Vol 40 (11) ◽  
pp. 3315-3318 ◽  
Author(s):  
M. Rylek ◽  
F. Kaštánek ◽  
L. Nývlt ◽  
J. Kratochvíl
Keyword(s):  
Gas Flow ◽  
Flow Through ◽  
Sieve Plates ◽  
Free Area

scholarly journals A Study on Liquid Leak Rates in Packing Seals

2021 ◽  
Vol 11 (4) ◽  
pp. 1936
Author(s):  
Abdel-Hakim Bouzid
Keyword(s):  
Environmental Protection ◽  
Liquid Flow ◽  
Environmental Protection Agency ◽  
Gas Flow ◽  
Outer Boundary ◽  
Health And Safety ◽  
Toxic Substances ◽  
Packing Materials ◽  
Thickness Change ◽  
Flow Through

The accurate prediction of liquid leak rates in packing seals is an important step in the design of stuffing boxes, in order to comply with environmental protection laws and health and safety regulations regarding the release of toxic substances or fugitive emissions, such as those implemented by the Environmental Protection Agency (EPA) and the Technische Anleitung zur Reinhaltung der Luft (TA Luft). Most recent studies conducted on seals have concentrated on the prediction of gas flow, with little to no effort put toward predicting liquid flow. As a result, there is a need to simulate liquid flow through sealing materials in order to predict leakage into the outer boundary. Modelling of liquid flow through porous packing materials was addressed in this work. Characterization of their porous structure was determined to be a key parameter in the prediction of liquid flow through packing materials; the relationship between gland stress and leak rate was also acknowledged. The proposed methodology started by conducting experimental leak measurements with helium gas to characterize the number and size of capillaries. Liquid leak tests with water and kerosene were then conducted in order to validate the predictions. This study showed that liquid leak rates in packed stuffing boxes could be predicted with reasonable accuracy for low gland stresses. It was found that internal pressure and compression stress had an effect on leakage, as did the thickness change and the type of fluid. The measured leak rates were in the range of 0.062 to 5.7 mg/s for gases and 0.0013 and 5.5 mg/s for liquids.

Comparing the Effects of Immersed Versus Land-Based High-Intensity Interval Cycling on Energy Intake, Appetite Sensations and Perceived Exertion Among Healthy Men

2021 ◽  
pp. 003151252110073
Author(s):  
Lore Metz ◽  
Laurie Isacco ◽  
Maud Miguet ◽  
Pauline Genin ◽  
David Thivel ◽  
...  
Keyword(s):  
Energy Intake ◽  
High Intensity ◽  
Perceived Exertion ◽  
Area Under The Curve ◽  
Macronutrient Intake ◽  
Healthy Men ◽  
High Intensity Interval ◽  
Interval Cycling ◽  
Desire To Eat ◽  
The Relationship

Immersed exercise has been shown to induce higher energy expenditure and no difference or increase in food intake compared with similar exercise on land. In this study, we compared the effects of acute high-intensity cycling performed on land versus when immersed on subsequent energy intake (EI), appetite sensations and perceived exertion (RPE) in healthy men. Ten participants in a postprandial condition completed three experimental visits in a randomized order: a control condition (CONT); a high-intensity interval cycling exercise performed on land (HIIE-L) and the same exercise while immersed in water (HIIE-A) with a similar targeted heart rate. We observed no difference in energy and macronutrient intake and in area under the curve (AUC) for appetite sensations between sessions. The RPE at the end of HIIE-L was negatively correlated with EI (r=–0.67; p < 0.05), AUC for hunger (r=–0.86, p < 0.01), desire to eat (r=–0.78, p < 0.05) and prospective food consumption (r=–0.86, p < 0.01). Conversely, the RPE at the end of HIIE-L was positively correlated with AUC for fullness (r = 0.76 , p < 0.05). No such correlations were observed for HIIE-A. The present study was the first to observe that immersion did not influence EI after HIIE cycling, but immersion blunted the relationship between session RPE and subsequent energy intake and appetite sensations relative to HIIE on land.

Observation of Pressure Drop Behavior in an Operating Fuel Cell Stack

2005 ◽  
Author(s):  
Frano Barbir ◽  
Haluk Gorgun ◽  
Xinting Wang
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Proton Exchange Membrane ◽  
Proton Exchange ◽  
Cathode Side ◽  
Fuel Cell Stack ◽  
Flow Through ◽  
Drying Conditions ◽  
Exchange Membrane ◽  
The Relationship

Pressure drop on the cathode side of a PEM (Proton Exchange Membrane) fuel cell stack has been studied and used as a diagnostic tool. Since the Reynolds number at the beginning of the flow field channel was <250, the flow through the channel is laminar, and the relationship between the pressure drop and the flow rate is linear. Some departure from linearity was observed when water was either introduced in the stack or produced inside the stack in the electrochemical reaction. By monitoring the pressure drop in conjunction with the cell resistance in an operational fuel cell stack, it was possible to diagnose either flooding or drying conditions inside the stack.

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