Scaling Relationships for the Total Pressure in Orificed Hollow Cathodes

2019 ◽  
Author(s):  
Pierre-Yves Taunay ◽  
Christopher J. Wordingham ◽  
Edgar Choueiri
Keyword(s):  
Total Pressure ◽  
Hollow Cathodes ◽  
Scaling Relationships

Scaling of Incidence Variations With Inlet Distortion for a Transonic Axial Compressor

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
D. J. Hill ◽  
J. J. Defoe
Keyword(s):  
Total Pressure ◽  
Incidence Angle ◽  
Computational Cost ◽  
Force Model ◽  
Flow Angle ◽  
Total Enthalpy ◽  
Transonic Compressor ◽  
Inlet Distortion ◽  
Scaling Relationships ◽  
The Impact

Abstract This paper numerically explores the manner in which blade row inlet incidence variation scales with various distortion patterns and intensities. The objectives are to (1) identify the most appropriate parameter whose circumferential variation can be used to assess scaling relationships of a transonic compressor and (2) use this parameter to evaluate two types of non-uniform inflow patterns, vertically stratified total pressure distortions and radially stratified total enthalpy and total pressure distortions. A body force model of the blade rows is employed to reduce computational cost; the approach has been shown to capture distortion transfer and to be able to predict upstream flow redistribution with inlet distortion. Diffusion factor is shown to be an inadequate proxy for streamline loss generation in non-uniform flow, leading to the choice of incidence angle variations as the metric for which we assess scaling relationships. Posteriori scaling of circumferential flow angle variation based on the maximum incidence excursion for varying distortion intensity yields an accurate method for prediction of the impact for other distortion intensities; linear regression of the maximum variation in incidence around the annulus as a function of distortion intensity had R2 > 0.97 for all spanwise locations examined in both the rotor and stator for both vertically and radially stratified distortions. However, changes to far upstream distortion shape yield highly non-linear incidence variation scaling; the results suggest that the pitchwise gradients of far upstream total pressure govern the degree of linearity for incidence variation scaling.

Total pressure in thermionic orificed hollow cathodes: Controlling mechanisms and their relative importance

2022 ◽  
Vol 131 (1) ◽  
pp. 013303
Author(s):  
Pierre-Yves C. R. Taunay ◽  
Christopher J. Wordingham ◽  
Edgar Y. Choueiri
Keyword(s):  
Total Pressure ◽  
Relative Importance ◽  
Hollow Cathodes

An empirical scaling relationship for the total pressure in hollow cathodes

2018 ◽  
Author(s):  
Pierre-Yves C. Taunay ◽  
Christopher J. Wordingham ◽  
Edgar Choueiri
Keyword(s):  
Total Pressure ◽  
Hollow Cathodes ◽  
Scaling Relationship

Assessing the Impact of the Inlet Total Pressure Distortion on the Turbofan Thrust

2018 ◽  
pp. 19-30
Author(s):  
Yu. A. Ezrokhi ◽  
E. A. Khoreva
Keyword(s):  
Total Pressure ◽  
External Compression ◽  
Average Value ◽  
Inlet Distortion ◽  
Air Inlet ◽  
Engine Thrust ◽  
Relative Value ◽  
Main Effect ◽  
Pressure Recovery Factor ◽  
The Impact

The paper considers techniques to develop a mathematical model using a method of «parallel compressors». The model is intended to estimate the impact of the air inlet distortion on the primary parameters of the aero-engine.  The paper presents rated estimation results in the context of twin spool turbofan design for two typical cruiser modes of flight of the supersonic passenger jet. In estimation the base values σbase and the average values of the inlet ram recovery σave remained invariable. Thus, parametrical calculations were performed for each chosen relative value of the area of low-pressure region.The paper shows that an impact degree of the inlet distortion on the engine thrust for two modes under consideration is essentially different. In other words, if in the subsonic mode the impact assessment can be confined only to taking into account the influence of decreasing average values of the inlet total pressure, the use of such an assumption in the supersonic cruiser mode may result in considerable errors.With invariable values of the pressure recovery factor at the engine intake, which correspond to the speed of flight for a typical air inlet of external compression σbase, and average value σave, a parameter Δσuneven  has the main effect on the engine thrust, and degree of this effect essentially depends on a difference between σave and σbase values.

Rise of total pressure near the stagnation point on a sphere

AIAA Journal ◽  
2002 ◽  
Vol 40 ◽  
pp. 576-579
Author(s):  
J. C. Williams III
Keyword(s):  
Stagnation Point ◽  
Total Pressure

Volumes and Surface Areas: Geometries and Scaling Relationships between Coarse- Grained and Atomic Structures

2014 ◽  
Vol 20 (8) ◽  
pp. 1208-1222 ◽  
Author(s):  
Daniel Flatow ◽  
Sumudu Leelananda ◽  
Aris Skliros ◽  
Andrzej Kloczkowski ◽  
Robert Jernigan
Keyword(s):  
Coarse Grained ◽  
Atomic Structures ◽  
Scaling Relationships ◽  
Surface Areas

Cw CO2 laser driven oxidation of some perhalogenocycloalkenes

1991 ◽  
Vol 56 (2) ◽  
pp. 398-405 ◽  
Author(s):  
Josef Pola ◽  
Jaroslav Včelák ◽  
Zdeněk Chvátal
Keyword(s):  
Co2 Laser ◽  
Total Pressure ◽  
Diels Alder ◽  
Title Reaction ◽  
Consecutive Reactions ◽  
Cw Co2 Laser

The title reaction of hexafluorocyclobutene, 1,2-dichloro-3,3,4,4-tetrafluorocyclobutene and decafluorocyclohexene studied at total pressure 13.3 and 16 kPa yield oxalyl halides COX.COX (X = F, Cl) and C2F4 that undergo consecutive reactions to COF2, CO and X2. The oxidation of decafluorocyclohexene is preceded by retro-Diels-Alder decomposition affording hexafluorocyclobutene and C2F4. Two alternative mechanisms for the oxidation of the cyclobutenes are presented, one involving a novel cleavage of intermediary bicyclic dioxetanes. The decomposition of oxalyl fluoride into COF2 and CO is favored over its oxidation.

Hydrodesulphurization of thiophene over zirconia and alumina supported Co-Mo catalysts

1989 ◽  
Vol 54 (8) ◽  
pp. 2064-2068 ◽  
Author(s):  
Jiří Sedláček ◽  
Zdeněk Vít
Keyword(s):  
Total Pressure ◽  
Supported Catalysts ◽  
Atomic Concentration ◽  
Commercial Sample ◽  
Sulphur Oxidation ◽  
Como Catalysts ◽  
Zirconia Support ◽  
Como Catalyst ◽  
Concentration Ratios

The zirconia supported CoMo catalysts and the commercial sample CoMo/Al2O3 were characterized by XPS measurements and by testing of activity in the HDS of thiophene at 280 °C and 1 MPa of total pressure. The XPS measurements revealed the better reducibility of molybdenum, higher sulphidability of cobalt and the absence of surface sulphur oxidation in the presence of zirconia support. The surface atomic concentration ratios S/Mo were 1.2 and 2.2 for zirconia and alumina supported catalysts, respectively. The activity of the zirconia supported CoMo catalyst normalized to the overal amounts of active metals was lower than that of the commercial CoMo/Al2O3 catalyst.

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