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

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.

scholarly journals Neutral density map of Hall thruster plume expansion in a vacuum chamber

2005 ◽  
Vol 76 (5) ◽  
pp. 053509 ◽  
Author(s):  
Mitchell L. R. Walker ◽  
Alec D. Gallimore
Keyword(s):  
Vacuum Chamber ◽  
Hall Thruster ◽  
Neutral Density ◽  
Plume Expansion ◽  
Density Map

scholarly journals Vacuum chamber pressure effects on thrust measurements of low Reynolds number nozzles

1986 ◽  
Vol 2 (5) ◽  
pp. 385-389 ◽  
Author(s):  
James S. Sovey ◽  
Paul F. Penko ◽  
Stanley P. Grisnik ◽  
Margaret V. Whalen
Keyword(s):  
Reynolds Number ◽  
Vacuum Chamber ◽  
Low Reynolds Number ◽  
Pressure Effects ◽  
Chamber Pressure ◽  
Low Reynolds

Design and Testing of a Punching-on-Film Precision Hole Seeder for Peanuts

2020 ◽  
Vol 63 (6) ◽  
pp. 1685-1696
Author(s):  
Jianming Kang ◽  
Qiangji Peng ◽  
Chunyan Zhang ◽  
Ningning Zhang ◽  
Huimin Fang
Keyword(s):  
Vacuum Chamber ◽  
Field Experiments ◽  
Operating Principle ◽  
Chamber Pressure ◽  
List Type ◽  
Study Results ◽  
Irrigation Pipes ◽  
Precision Hole ◽  
Seed Metering Device ◽  
Design And Testing

HighlightsThe designed precision seeder meets the agronomic requirements for on-film hole seeding.Influencing factors were found by studying the operating principle and key parameters.A response model was successfully built and verified by experiments.This study provides technical support for punching-on-film hole seeding technology.Abstract. To satisfy the agronomic requirements for punching-on-film precision seeding of peanuts, a precision hole seeder was designed in this study. The seeder can perform simultaneous functions of film mulching, film punching, pipe laying, precision hole seeding, and seed covering. The overall structure and operating principle of the device were analyzed, and its major components, including a seed-metering device, soil-covering roller, and drip irrigation pipes, were theoretically studied. To optimize the operating parameters and achieve favorable performance, a three-factor quadratic orthogonal test was performed to test the effects of the vacuum chamber pressure, advancing speed of the seeder, and height of the type hole boss on the seeding performance; the variance and range of the test results were analyzed accordingly. Through the field experiments, when the vacuum chamber pressure, advancing speed of the seeder, and height of the type hole boss were optimized to 7.5 kPa, 4.2 km h-1, 5.3 mm, respectively, the qualification index, re-seeding index, and miss-seeding index of the seeder were 92.7%, 3.8%, and 3.5%, respectively. Thus, the developed seeder satisfies the agronomic requirements, and the study results provide a technical reference for the punching-on-film precision seeding of peanuts. Keywords: Model, Peanut, Precision seeding of peanut, Punching-on-film hole, Seeder.

The Seal System in Aerostatic Journal Bearings for High Vacuum Chambers

2004 ◽  
Vol 126 (2) ◽  
pp. 310-315 ◽  
Author(s):  
S. Yoshimoto ◽  
Y. Yoshida ◽  
K. Yagi
Keyword(s):  
Pressure Distribution ◽  
Vacuum Chamber ◽  
Journal Bearing ◽  
High Vacuum ◽  
Journal Bearings ◽  
Vacuum Pump ◽  
Chamber Pressure ◽  
Design Parameters ◽  
Vacuum Chambers ◽  
High Vacuum Chamber

This paper investigates the performance of a seal system for an aerostatic journal bearing used in a high vacuum chamber. The seal system consists of axially spaced viscous seals and annular exhaust grooves that are located between the viscous seals. Each exhaust groove is coupled to a separate vacuum pump in order to achieve a vacuum chamber pressure of less than 10−3 Pa. The vacuum chamber pressure is affected by design parameters such as the number of viscous seal stages, seal length, seal gap, and exhaust tube conductance. The influence of these design parameters on the pressure distribution across seal regions and the vacuum chamber pressure are discussed theoretically. It is subsequently shown that an aerostatic journal bearing with three-stage seal system installed can obtain a reduction in the vacuum chamber pressure almost to the ultimate pressure of a vacuum pump, providing there is no leak or outgassing from materials.

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.

Sign in / Sign up

Export Citation Format

Share Document