Influence of the Reference State in the SLW Model for Flows With Strong Temperature and Pressure Gradients

2002 ◽  
Author(s):  
T. Badinand ◽  
T. H. Fransson
Keyword(s):  
Radiative Heat ◽  
Reference Temperature ◽  
Pressure Gradients ◽  
Absorption Coefficients ◽  
Local Conditions ◽  
High Temperature And Pressure ◽  
Small Influence ◽  
Temperature And Pressure ◽  
Reference Pressure ◽  
Pressure Changes

Radiative heat transfer in a real case showing high temperature and pressure gradients is calculated with a global model (SLW) with and without re-scaling of the absorption coefficients to the local conditions. Changes in radiative heat flux to the walls for different reference temperatures and reference pressures are studied. Changes in reference pressure are shown to have a small influence compared to changes in reference temperature, except if the pressure is less than 10 bars for a high-pressure case. The use of the scaling does decrease the dependency on the reference condition. The highest differences obtained with strong reference temperature or pressure changes (800K and 30.105 Pa) are of about 15% and 7% respectively. For smaller changes, an uncertainty of 5% could be assumed.

Pressure Gradients Affecting the Labyrinth during Hypobaric Pressure

1997 ◽  
Vol 106 (6) ◽  
pp. 495-502 ◽  
Author(s):  
Konrád S. Konrádsson ◽  
Björn I. R. Carlborg ◽  
Joseph C. Farmer
Keyword(s):  
Cerebrospinal Fluid ◽  
Eustachian Tube ◽  
Ambient Pressure ◽  
Pressure Gradients ◽  
Cochlear Aqueduct ◽  
Fluid Compartment ◽  
Large Pressure ◽  
Fluid Compartments ◽  
Pressure Changes ◽  
Considerable Pressure

Hypobaric effects on the perilymph pressure were investigated in 18 cats. The perilymph, tympanic cavity, cerebrospinal fluid, and systemic and ambient pressure changes were continuously recorded relative to the atmospheric pressure. The pressure equilibration of the eustachian tube and the cochlear aqueduct was studied, as well as the effects of blocking these channels. During ascent, the physiologic opening of the eustachian tube reduced the pressure gradients across the tympanic membrane. The patent cochlear aqueduct equilibrated perilymph pressure to cerebrospinal fluid compartment levels with a considerable pressure gradient across the oval and round windows. With the aqueduct blocked, the pressure decrease within the labyrinth and tympanic cavities was limited, resulting in large pressure gradients toward the chamber and the cerebrospinal fluid compartments, respectively. We conclude that closed cavities with limited pressure release capacities are the cause of the pressure gradients. The strain exerted by these pressure gradients is potentially harmful to the ear.

scholarly journals Lead Recovery from Solid Residues of Copper Industry Using Triethylenetetramine Solution

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 546
Author(s):  
Mateusz Ciszewski ◽  
Andrzej Chmielarz ◽  
Zbigniew Szołomicki ◽  
Michał Drzazga ◽  
Katarzyna Leszczyńska-Sejda
Keyword(s):  
Lead Extraction ◽  
Pressure Leaching ◽  
Base Metals ◽  
Lead Carbonate ◽  
Pure Lead ◽  
Industrial Processing ◽  
High Temperature And Pressure ◽  
Lead Recovery ◽  
Temperature And Pressure ◽  
Increasing Temperature

Industrial processing of mineral ores and concentrates generates large amounts of solid residues, which can be landfilled or further processed to recover selected elements depending on its economical profitability. Pressure leaching is a technology enabling high recovery of base metals like copper and zinc, transferring others like lead and iron to the solid residue. High temperature and pressure of such leaching leads to formation of sparingly soluble lead jarosite (plumbojarosite). The load of lead landfilled as solid residues resulting from such operation is so big that its recovery is perspective and crucial for waste-limiting technologies. This paper is devoted to lead extraction from pressure leaching residues using triethylenetetramine solution and then its precipitation as a commercial lead carbonate. The highest obtained recovery of lead was 91.3%. Additionally, presented technology allows to manage and recycle amine solution and reuse solid products. Produced pure lead carbonate can be directly added to smelting, not increasing temperature within the furnace.

scholarly journals Assessment of Piezoelectric Sensors for the Acquisition of Steady Melt Pressures in Polymer Extrusion

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 66
Author(s):  
Sónia Costa ◽  
Paulo Teixeira ◽  
José Covas ◽  
Loic Hilliou
Keyword(s):  
Polymer Processing ◽  
Piezoelectric Transducers ◽  
Piezoelectric Sensors ◽  
Flow Curves ◽  
Signal Drift ◽  
Temperature And Pressure ◽  
Pressure Independent ◽  
Pressure Changes ◽  
Different Levels ◽  
Slit Die

Piezoelectric sensors have made their way into polymer processing and rheometry applications, in particular when small pressure changes with very fast dynamics are to be measured. However, no validation of their use for steady shear rheometry is available in the literature. Here, a rheological slit die was designed and constructed to allow for the direct comparison of pressure data measured with conventional and piezoelectric transducers. The calibration of piezoelectric sensors is presented together with a methodology to correct the data from the inherent signal drift, which is shown to be temperature and pressure independent. Flow curves are measured for polymers showing different levels of viscoelasticity. Piezoelectric slit rheometry is validated and its advantage for the rheology of thermodegradable materials with viscosity below 100 Pa·s is highlighted.

scholarly journals Compensation of phase drifts caused by ambient humidity, temperature and pressure changes for continuously operating interferometers

2019 ◽  
Vol 14 (11) ◽  
pp. P11016-P11016
Author(s):  
K.J. Brunner ◽  
J. Knauer ◽  
J. Meineke ◽  
M. Stern ◽  
M. Hirsch ◽  
...  
Keyword(s):  
Ambient Humidity ◽  
Temperature And Pressure ◽  
Pressure Changes

scholarly journals Fatigue simulation of a short fiber re-inforced oil-filter under high temperature and pressure load

2018 ◽  
Vol 213 ◽  
pp. 207-214 ◽  
Author(s):  
Michael Hack ◽  
Wolfgang Korte ◽  
Stefan Sträßer ◽  
Matthias Teschner
Keyword(s):  
High Temperature ◽  
Short Fiber ◽  
Pressure Load ◽  
High Temperature And Pressure ◽  
Temperature And Pressure

DECOMPOSITION PRESSURES OF FERRIC SULPHATE AND ALUMINUM SULPHATE

1960 ◽  
Vol 38 (11) ◽  
pp. 2196-2202 ◽  
Author(s):  
N. A. Warner ◽  
T. R. Ingraham
Keyword(s):  
Gas Phase ◽  
Static System ◽  
Ferric Sulphate ◽  
Kcal Mole ◽  
Aluminum Sulphate ◽  
Temperature And Pressure ◽  
Pressure Changes ◽  
Mercury Manometer ◽  
Decomposition Pressure ◽  
Gas Pressures

The gas pressures over samples of anhydrous ferric sulphate and anhydrous aluminum sulphate have been measured in a static system, using a mercury manometer in which the exposed surface was covered with a flexible Pyrex bellows. The calculated ΔH for the decomposition of Fe2(SO4)3 was +135.4 kcal/mole. It was not possible to calculate the ΔH for the Al2(SO4)3 decomposition, because a discrete aluminum oxide with singular thermodynamic properties was not obtained.In the Fe2(SO4)3 system, the fraction of SO3 in the gas phase was found to be almost constant over the range of temperature and pressure changes used in the study.At any given temperature, the decomposition pressure over a ferric sulphate sample is greater than that over an aluminum sulphate sample, thus indicating that preferential decomposition of ferric sulphate should be thermodynamically feasible in mixtures of ferric sulphate and aluminum sulphate.

Creep Modeling of Welded Joints Using the Theta Projection Concept and Finite Element Analysis

1999 ◽  
Vol 122 (1) ◽  
pp. 22-26 ◽  
Author(s):  
M. Law ◽  
W. Payten ◽  
K. Snowden
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Welded Joints ◽  
Creep Model ◽  
Projection Data ◽  
Predictive Capability ◽  
Element Analysis ◽  
High Temperature And Pressure ◽  
Temperature And Pressure

Modeling of welded joints under creep conditions with finite element analysis was undertaken using the theta projection method. The results were compared to modeling based on a simple Norton law. Theta projection data extends the accuracy and predictive capability of finite element modeling of critical structures operating at high temperature and pressure. In some cases analyzed, it was found that the results diverged from those gained using a Norton law creep model. [S0094-9930(00)00601-6]

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