Investigation of a pulsed electrothermal thruster
Exhaust velocity and thrust measurements are performed on a pulsed electrothermal thruster using polyethylene and Teflon propellants. The results verify theoretical predictions of equilibrium flow in the nozzle, resulting in substantial recovery of the energy of dissociation and ionization. The thruster is tested in an unsteady mode (15 micro sec current pulse and 15 cm discharge length) and in a quasi-steady mode (48 micro sec current pulse and 5 cm discharge length). All tests are run at 2 kJ. The exhaust velocity of the propellant mass exiting during the current pulse is measured with two types of time of flight probes, and the impulse bit is measured on a thrust stand. It is inferred from both theory and experiment that an additional amount of mass is exhausted after the pulse. The measured thrust to power ratio for polyethylene is T/P 0.10 NkW at 21 km/sec in the unsteady mode, and T/P .053 N/kW at 27 km/sec in the quasi-steady mode, where the velocities are measured by the time-of-flight probes. For Teflon propellant, T/P .20 N/kW at 15 km/sec (unsteady mode) and 0.090 N/kW at 20 km/sec (quasi-steady mode). The discharge pressure and temperature predicted by a computational model for polyethylene are consistent with the measured thrust and discharge resistance.
- Research Organization:
- GT-Devices, Alexandria, VA (USA)
- OSTI ID:
- 6619086
- Report Number(s):
- N-84-12227; NASA-CR-168266
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
330000* -- Advanced Propulsion Systems
EXHAUST GASES
FLUIDS
FLUORINATED ALIPHATIC HYDROCARBONS
GASEOUS WASTES
GASES
HALOGENATED ALIPHATIC HYDROCARBONS
MATERIALS
MEASURING INSTRUMENTS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYETHYLENES
POLYMERS
POLYOLEFINS
POLYTETRAFLUOROETHYLENE
PROPELLANTS
PROPULSION
ROCKETS
SPECTROMETERS
SYNTHETIC MATERIALS
TEFLON
THRUSTERS
TIME-OF-FLIGHT SPECTROMETERS
VELOCITY
WASTES