Effects of Variable Chamber Pressure on Swirl Coaxial Injection: A Cold Flow Study

2010 ◽  
Author(s):  
Chad Eberhart ◽  
David Lineberry ◽  
Marlow Moser
Keyword(s):  
Chamber Pressure ◽  
Cold Flow ◽  
Flow Study

Experimental Investigation of Solid Attitude Control System Using Proportional Pintle Thrusters

2015 ◽  
Vol 723 ◽  
pp. 131-135
Author(s):  
Heng Chang ◽  
Yi Bai Wang ◽  
Yu Liu ◽  
Jin Qing Wu
Keyword(s):  
Control System ◽  
Attitude Control ◽  
Collaborative Work ◽  
Chamber Pressure ◽  
Attitude Control System ◽  
Thrust Chamber ◽  
Cold Flow ◽  
Flow Test ◽  
Thrust Control ◽  
Control Principle

In order to investigate the characteristics of solid attitude control system (SACS) using proportional pintle thrusters, an ACS comprised of dual collaborative thrusters was designed and studied by theory and cold-flow test. Experiments were conducted to ascertain thrust variation at different pintle locations. With the purpose of studying thrust control principle, the thrust, chamber pressure and pintle displacement of two thrusters were measured, which worked differentially in the process. Results show that a nearly linear relationship is found between the thrust and valve pintle position and the two thrusters can work synchronous to produce a resultant force, whose direction and value can vary continuously. Besides, collaborative work mode of dual thrusters is conducive to the stabilization of chamber pressure which is beneficial to the choice of propellant.

The effect of gravity on turbulent, premixed flame propagation - A preliminary cold flow study

1997 ◽  
Author(s):  
M. Disseau ◽  
S. Menon ◽  
J. Jagoda ◽  
R. Sujith ◽  
M. Disseau ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Premixed Flame ◽  
Turbulent Premixed Flame ◽  
Cold Flow ◽  
Flow Study ◽  
Turbulent Premixed

Cold flow studies in a vortex thrust chamber

2018 ◽  
Vol 91 (1) ◽  
pp. 69-77
Author(s):  
Rajesh T.N. ◽  
T.J. Sarvoththama Jothi ◽  
Jayachandran T.
Keyword(s):  
Design Methodology ◽  
Practical Implication ◽  
Chamber Pressure ◽  
Flow Conditions ◽  
Mixture Ratio ◽  
Content Type ◽  
Thrust Chamber ◽  
Cold Flow ◽  
Practical Implications ◽  
Key Parameter

Purpose The purpose of this paper is to estimate the chamber pressure and flow behaviour in a vortex thrust chamber (VTC) during the cold flow with hydrogen and oxygen as propellants. Design/methodology/approach Experiments are carried out in a VTC with a different mixture ratio of hydrogen and oxygen. The pressures developed inside the VTC are measured. Numerical simulations are carried out to understand the flow patterns of fuel and oxidizer inside the VTC. Findings The chamber pressure is influenced by the type of injection of propellant and mixture ratio. Tangential injection of propellant is the key parameter for an increase of the chamber pressure of the VTC. Research limitations/implications The pressure measurements are carried out in cold flow conditions without combustion happening in the VTC. Practical implications The practical implication is that when the combustion in the VTC ceases, the thrust generated due to the propellants in cold flow conditions can be assessed. Originality/value The VTC with the tangential injection of propellant generates higher chamber pressure.

scholarly journals Vacuum Chamber Pressure Maps of a Hall Thruster Cold-Flow Expansion

2004 ◽  
Vol 20 (6) ◽  
pp. 1127-1132 ◽  
Author(s):  
Mitchell L. R. Walker ◽  
Alec D. Gallimore ◽  
Iain D. Boyd ◽  
Chunpei Cai
Keyword(s):  
Vacuum Chamber ◽  
Hall Thruster ◽  
Chamber Pressure ◽  
Cold Flow

Residual Gas Reaction in the Electron Microscope: II The Design of a Gas-Control Chamber for Quantitative Observations

1969 ◽  
Vol 27 ◽  
pp. 82-83
Author(s):  
Chester J. Calbick ◽  
Richard E. Hartman
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Local Environment ◽  
Chamber Pressure ◽  
Objective Lens ◽  
Ion Pump ◽  
Quantitative Studies ◽  
Precise Knowledge ◽  
Differential Pumping ◽  
And Control

Quantitative studies of the phenomenon associated with reactions induced by the electron beam between specimens and gases present in the electron microscope require precise knowledge and control of the local environment experienced by the portion of the specimen in the electron beam. Because of outgassing phenomena, the environment at the irradiated portion of the specimen is very different from that in any place where gas pressures and compositions can be measured. We have found that differential pumping of the specimen chamber by a 4" Orb-Ion pump, following roughing by a zeolite sorption pump, can produce a specimen-chamber pressure 100- to 1000-fold less than that in the region below the objective lens.

Studies of the scanning ion beam sputter-cleaned MgO crystal surface by scanning reflection electron microscopy

1987 ◽  
Vol 45 ◽  
pp. 144-145
Author(s):  
H.-J. Ou ◽  
J. M. Cowley ◽  
A. A. Higgs
Keyword(s):  
Crystal Surface ◽  
Ion Beam ◽  
Carbon Film ◽  
Surface Region ◽  
Bulk Sample ◽  
Chamber Pressure ◽  
Specimen Preparation ◽  
Detailed Surface ◽  
Gate Control ◽  
Reflection Electron Microscopy

A scanning ion gun system has been installed on the specimen preparation chamber (pressure ∼5xl0-8 torr) of the VG-HB5 STEM microscope. By using the specimen current imaging technique, it is possible to use an ion beam to sputter-clean the preferred surface region on a bulk sample. As shown in figure 1, the X-Y raster-gate control of the scanning unit for the Krato Mini-Beam I is used to minimize the beam raster area down to a 800μm x800μm square region. With beam energy of 2.5KeV, the MgO cleavage surface has been ion sputter-cleaned for less than 1 minute. The carbon film or other contaminant, introduced during the cleavage process in air, is mostly removed from the MgO crystal surfaces.The immediate SREM inspection of this as-cleaned MgO surface, within the adjacent STEM microscope, has revealed the detailed surface structures of atomic steps, which were difficult to observe on the as-cleaved MgO surfaces in the previous studies.

Electron behavior in the gaseous environment of the ESEM chamber

1996 ◽  
Vol 54 ◽  
pp. 838-839 ◽  
Author(s):  
S.A. Wight
Keyword(s):  
Secondary Electron ◽  
High Vacuum ◽  
Beam Current ◽  
Chamber Pressure ◽  
Environmental Scanning ◽  
Carbon Block ◽  
Faraday Cup ◽  
X Ray ◽  
Gaseous Environment ◽  
Working Distance

Measurements of electrons striking the sample in the Environmental Scanning Electron Microscope (ESEM) are needed to begin to understand the effect of the presence of the gas on analytical measurements. Accurate beam current is important to x-ray microanalysis and it is typically measured with a faraday cup. A faraday cup (Figure 1) was constructed from a carbon block embedded in non-conductive epoxy with a 45 micrometer bore platinum aperture over the hole. Currents were measured with an electrometer and recorded as instrument parameters were varied.Instrument parameters investigated included working distance, chamber pressure, condenser percentage, and accelerating voltage. The conditions studied were low vacuum with gaseous secondary electron detector (GSED) voltage on; low vacuum with GSED voltage off; and high vacuum (GSED off). The base conditions were 30 kV, 667 Pa (5 Torr) water vapor, 100,000x magnification with the beam centered inside aperture, GSED voltage at 370 VDC, condenser at 50%, and working distance at 19.5 mm. All modifications of instrument parameters were made from these conditions.

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