Accession Number:

ADA429661

Title:

Meso and Micro Scale Propulsion Concepts for Small Spacecraft

Descriptive Note:

Final technical rept. Jun 2001-Feb 2004

Corporate Author:

PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MECHANICAL AND NUCLEAR ENGINEERING

Report Date:

2004-12-24

Pagination or Media Count:

50.0

Abstract:

A mesomicro-scale liquid propellant thruster was designed and developed for small spacecraft. Gas-phase combustion was stabilized in small combustion chambers approx. 10-200 cu mm using vortex flows. For liquid propellant steady-state operation, the propellant was injected directly into the chamber tangentially along the combustor wall. Heat feedback from the flame, once ignited, decomposed and gasified the liquid propellant. Although the propellant of interest was a HAN-based liquid propellant, initial studies were conducted with liquid nitromethane. Operation of the combustion chamber with pure nitromethane at a chamber pressure of 8 atm was achieved. To gasify and initially ignite a HAN-based propellant, techniques that make use of the electrolytic character of the propellant were investigated. In particular, exposure of small liquid droplets to voltage drops of approx. 10 volts were shown to initiate electrochemical reactions and eventually thermal reactions that gasify and, in some instances, ignite the droplet. Implementation of this concept into the microthruster was estimated to reduce power requirements and improve thermal management during ignition. Combustion chambers and nozzles were fabricated from ceramics alumina because of the required high-flame temperatures required to sustain gas-phase reaction. Operation of thrusters on hydrogen-air-oxygen mixtures at combustion chamber pressures as high as 8 atm was demonstrated to produce characteristic velocity efficiencies of approximately 90.

Subject Categories:

  • Physical Chemistry
  • Manufacturing and Industrial Engineering and Control of Production Systems
  • Fluid Mechanics
  • Combustion and Ignition
  • Liquid Rocket Propellants

Distribution Statement:

APPROVED FOR PUBLIC RELEASE