Specification for aircraft gaseous oxygen replenishment connection (inch dimensions)

1986 ◽  
Keyword(s):  
Gaseous Oxygen

DEFLAGRATION-TO-DETONATION TRANSITION IN A STRATIFIED SYSTEM “GASEOUS OXYGEN-LIQUID FILM OF N-DECANE”

2020 ◽  
Author(s):  
S. M. FROLOV ◽  
◽  
V. S. AKSENOV ◽  
I. O. SHAMSHIN ◽  
◽  
...  
Keyword(s):  
Liquid Film ◽  
Ignition Source ◽  
Gaseous Oxygen ◽  
Deflagration To Detonation Transition ◽  
Operation Process ◽  
Continuous Detonation ◽  
Smooth Channel ◽  
Detonation Transition ◽  
Run Up ◽  
X 24

Deflagration-to-detonation transition (DDT) in the system “gaseous oxygen- liquid film of n-decane” ' with a weak ignition source was obtained experimentally. In a series of experiments with ignition by an exploding wire that generates a weak primary shock wave (SW) with a Mach number ranging from 1.03 to 1.4, the DDT with the detonation run-up distances 1 to 4 m from the ignition source and run-up time 3 ms to 1.7 s after ignition was observed in a straight smooth channel of rectangular 54 x 24-millimeter cross section, 3 and 6 m in length with one open end. The DDT is obtained for relatively thick films with a thickness of 0. 3-0.5 mm, which corresponds to very high values of the overall fuel-to-oxygen equivalence ratios of 20-40. The registered velocity of the detonation wave (DW) was 1400-1700 m/s. In a number of experiments, a high-velocity quasi-stationary detonation-like combustion front was recorded running at an average velocity of 700-1100 m/s. Its structure includes the leading SW followed by the reaction zone with a time delay of 90 to 190 s. The obtained results are important for the organization of the operation process in advanced continuous-detonation and pulsed-detonation combustors of rocket and air-breathing engines with the supply of liquid fuel in the form of a wall film.

Preliminary Studies on Non-Reactive Flow Vortex Cooling

2019 ◽  
Vol 12 (3) ◽  
pp. 262-271
Author(s):  
T.N. Rajesh ◽  
T.J.S. Jothi ◽  
T. Jayachandran
Keyword(s):  
Combustion Chamber ◽  
Inner Core ◽  
Rocket Engine ◽  
Injection Pressure ◽  
Chamber Pressure ◽  
Reactive Flow ◽  
Stoichiometric Ratio ◽  
Gaseous Oxygen ◽  
Mixture Ratio ◽  
Vortex Combustion

Background: The impulse for the propulsion of a rocket engine is obtained from the combustion of propellant mixture inside the combustion chamber and as the plume exhausts through a convergent- divergent nozzle. At stoichiometric ratio, the temperature inside the combustion chamber can be as high as 3500K. Thus, effective cooling of the thrust chamber becomes an essential criterion while designing a rocket engine. Objective: A new cooling method of thrust chambers was introduced by Chiaverni, which is termed as Vortex Combustion Cold-Wall Chamber (VCCW). The patent works on cyclone separators and confined vortex flow mechanism for providing high propellant mixing with improved degree of turbulence inside the combustion chamber, providing the required notion for studies on VCCW. The flow inside a VCCW has a complex structure characterised by axial pressure losses, swirl velocities, centrifugal force, flow reversal and strong turbulence. In order to study the flow phenomenon, both the experimental and numerical investigations are carried out. Methods: In this study, non-reactive flow analysis was conducted with real propellants like gaseous oxygen and hydrogen. The test was conducted to analyse the influence of mixture ratio and injection pressure of the propellants on the chamber pressure in a vortex combustion chamber. A vortex combustor was designed in which the oxidiser injected tangentially at the aft end near the nozzle spiraled up to the top plate and formed an inner core inside the chamber. The fuel was injected radially from injectors provided near the top plate and the propellants were mixed in the inner core. This resulted in enhanced mixing and increased residence time for the fuel. More information on the flow behaviour has been obtained by numerical analysis in Fluent. The test also investigated the sensitivity of the tangential injection pressure on the chamber pressure development. Results: All the test cases showed an increase in chamber pressure with the mixture ratio and injection pressure of the propellants. The maximum chamber pressure was found to be 3.8 bar at PC1 and 2.7 bar at PC2 when oxidiser to fuel ratio was 6.87. There was a reduction in chamber pressure of 1.1 bar and 0.7 bar at PC1 and PC2, respectively, in both the cases when hydrogen was injected. A small variation in the pressure of the propellant injected tangentially made a pronounced effect on the chamber pressure and hence vortex combustion chamber was found to be very sensitive to the tangential injection pressure. Conclusion: VCCW mechanism has been to be found to be very effective for keeping the chamber surface within the permissible limit and also reducing the payload of the space vehicle.

Broadening of the Fine-Structure Raman Lines in Gaseous Oxygen

1971 ◽  
Vol 26 (10) ◽  
pp. 1639-1643
Author(s):  
S. Hess ◽  
H. F. P. Knaap
Keyword(s):  
Fine Structure ◽  
Relaxation Frequency ◽  
Collision Term ◽  
60 Ghz ◽  
Pressure Broadening ◽  
Gaseous Oxygen ◽  
Molecular Potential ◽  
Electronic Spin ◽  
Anti Stokes ◽  
Rayleigh Light

Abstract Due to the coupling between the rotational angular momentum and the electronic spin, the depolarized Rayleigh light scattered from gaseous oxygen shows Stokes and anti-Stokes satellites shifted by about 60 GHz. The broadening of these fine-structure Raman lines is investigated theoretically for high and medium pressures where the linewidth is determined by two contributions, one proportional and the other inversely proportional to the pressure, p. The linewidth in the pressure broadening region is given by a relaxation frequency which is obtained from the Waldmann-Snider collision term. The p-1 contribution to the linewidth is determined by the ratio of the second moment of the fine-structure freqencies (with respect to the center of the shifted line) and another relaxation frequency. Both relaxation frequencies are sensitive to the nonspherical part of the inter-molecular potential.

Isotope Exchange of Gaseous Oxygen with Oxide LaMno3+δ Nanograins Boundary

2010 ◽  
Vol 297-301 ◽  
pp. 1301-1305
Author(s):  
Anatoly Yakovlevich Fishman ◽  
Tatiana Eugenievna Kurennykh ◽  
Vladimir Borisovich Vykhodets ◽  
V.B. Vykhodets
Keyword(s):  
Activation Energy ◽  
Exchange Rate ◽  
Isotope Exchange ◽  
Shock Wave Loading ◽  
Wave Loading ◽  
Gaseous Oxygen ◽  
Exponential Factor ◽  
Significant Difference ◽  
Exponential Factors ◽  
Arrhenius Expression

Isotope exchange of oxygen 18О2 with the boundary of nanograins of oxide LaMnO3+ obtained by the method of shock-wave loading was investigated in the temperature range of 400 – 500 °C. It was established that the temperature dependence of the isotope exchange rate is described by the Arrhenius expression, the activation energy and the pre-exponential factor being 1.67 eV and 1.8∙102 cm/s, respectively. Comparison with literature data has shown that for oxide LaMnO3+, a significant difference in activation energies and pre-exponential factors is observed for the isotope exchange rate with a ‘defect-free’ surface and the nanograin boundary. In case of the boundary, these parameters were higher: the activation energy about two times, and the pre-exponential factor, by almost 7 orders of magnitude.

scholarly journals Valorization of secondary feedstocks from the agroindustry by selective catalytic oxidation to formic and acetic acid using the OxFA process

2021 ◽  
Author(s):  
Sebastian Ponce ◽  
Stefanie Wesinger ◽  
Daniela Ona ◽  
Daniela Almeida Streitwieser ◽  
Jakob Albert
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Reaction System ◽  
Value Added ◽  
Industrial Wastes ◽  
Raw Material ◽  
Gaseous Oxygen ◽  
Water As Solvent ◽  
Selective Catalytic Oxidation ◽  
Major Interest

AbstractThe selective oxidative conversion of seven representative fully characterized biomasses recovered as secondary feedstocks from the agroindustry is reported. The reaction system, known as the “OxFA process,” involves a homogeneous polyoxometalate catalyst (H8PV5Mo7O40), gaseous oxygen, p-toluene sulfonic acid, and water as solvent. It took place at 20 bar and 90 °C and transformed agro-industrial wastes, such as coffee husks, cocoa husks, palm rachis, fiber and nuts, sugarcane bagasse, and rice husks into biogenic formic acid, acetic acid, and CO2 as sole products. Even though all samples were transformed; remarkably, the reaction obtains up to 64, and 55% combined yield of formic and acetic acid for coffee and cocoa husks as raw material within 24 h, respectively. In addition to the role of the catalysts and additive for promoting the reaction, the influence of biomass components (hemicellulose, cellulose and lignin) into biogenic formic acid formation has been also demonstrated. Thus, these results are of major interest for the application of novel oxidation techniques under real recovered biomass for producing value-added products. Graphical abstract

scholarly journals The catalytic combination of hydrogen and oxygen at the surface of platinum

1936 ◽  
Vol 156 (888) ◽  
pp. 284-306 ◽  
Keyword(s):  
Room Temperature ◽  
Quantitative Measurement ◽  
Silver Oxide ◽  
Catalytic Properties ◽  
Metallic Surface ◽  
Metallic Silver ◽  
Mercury Vapour ◽  
Platinum Surface ◽  
Gaseous Oxygen ◽  
Low Pressures

Research on the catalysis by metals of the combination of hydrogen and oxygen at low pressures was commenced in these laboratories by Cooper in 1923. Investigating the catalytic properties of a short platinum filament subjected to various pre-treatments by heating it electrically in hydrogen or oxygen or in vacuo , he found that the metallic surface thus cleaned became so active at room temperature as to render the quantitative measurement of the catalysed reaction impossible. It was discovered also that mercury vapour is a very potent poison of the surface, the enormously active clean platinum surface being rendered completely inactive by exposure to mercury vapour for a few minutes: a fact noted but apparently insufficiently emphasized in a paper published by Chapman and Hall in 1929. Owing to the difficulties involved in wording with a catalyst of such high activity, the research was discontinued in favour of an investigation of the same reaction using silver instead of platinum, a clean surface of this metal having been found to catalyse the reaction at a convenient rate at room temperature. The following facts were established:— (1) At the temperature of the laboratory a surface of metallic silver adsorbs completely a quantity of gaseous oxygen sufficient to form a complete unimolecular layer of silver oxide. This adsorbed oxygen cannot, of course, be removed by evacuation.

The suboptimal donor: reduction of ischemic injury in fatty livers by gaseous oxygen persufflation

2000 ◽  
Vol 32 (1) ◽  
pp. 10 ◽  
Author(s):  
T Minor ◽  
R Tolba ◽  
S Akbar ◽  
T Dombrowski ◽  
A Müller
Keyword(s):  
Ischemic Injury ◽  
Gaseous Oxygen ◽  
Fatty Livers
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