Arcjet rocket

About: Arcjet rocket is a research topic. Over the lifetime, 1121 publications have been published within this topic receiving 9687 citations. The topic is also known as: Arcjet.

Comparison of Electron-Ion Recombination and Gas-Dynamic Expansion Rates in Freely Expanding Helium and Argon Plasmas

Abstract: : Equations coupling the collisional-radiative recombination and gas- dynamic phenomena for the centerline of the freely expanding plume of an argon and helium arcjet are developed and solved for the free electron density. The results of these calculations are used to ascertain the time rates of change of the free electron density attributable to the recombination and gas-dynamic processes separately. Experimental data are presented which support the conclusions drawn from the analytical results. Therefore, based on these results, a more detailed approach than the collisional-radiative recombination model is necessary for the correct description of recombination mechanisms in the rapidly changing environment of the expanding arcjet plume.

Development of Electromagnetic Acceleration Plasma Arcjet Generators for Titanium Nitride Reactive Spray Coatings.

Abstract: An electromagnetic acceleration plasma arcjet generator, which is called Magneto-Plasma-Dynamics (MPD) arcjet generator, has a coaxial electrode structure similar to those of conventional thermal arcjet generators. However, their acceleration mechanisms are different ; that is, in MPD arcjet generator, plasma is accelerated by the electromagnetic interaction between the discharge current and the magnetic field induced by it in MW-class input power operations during the discharge, although in thermal arcjet generators the working gas is accelerated aerodynamically through a straight or convergent-divergent nozzle. As a result, the MPD arcjet generator can produce higher-velocity, higher-temperature, higher-energy-density, and larger-area plasma than those of other conventional plasma torches can. These MPD plasma properties are effective for various material processes.This paper deals with a development of MPD arcjet generator for titanium nitride (TiN) reactive coatings. The MPD arcjet generator is equipped with a titanium cathode, and its working gas is nitrogen. The coatings were deposited onto steel substrate. The phase structure and the composition of the coatings were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD), and their Vickers hardnesses were measured. In addition, titanium particles that were generated by MPD arcjet generator ablation process were observed by means of SEM and electron probe micro analysis (EPMA). These analyses showed that the MPD spray process could successfully form dense and uniform titanium nitride coatings. The properties of the titanium nitride coatings were highly sensitive to the titanium cathode diameter and discharge current.

Preliminary investigation of a low power pulsed arcjet thruster

Abstract: A type of pulsed arcjet is examined which operates with gaseous helium propellant at powers from 100 to 1500 W and pulse rats from 360 to 6000 pulses per second. During the pulse, peak power is 50 to 250 kW generating chamber pressures of 10 to 50 atmospheres. The high operating pressure substantially reduces ionization in the 2.5 mm diameter x 12.5 mm long capillary and lowers frozen flow losses in the nozzle. The thruster thermal efficiency, measured calorimetrically, is 43 percent at 440 W and 8 mg/sec helium mass flow rate. Thruster performance trends are predicted by a time-dependent lumped-parameter model which includes heat exchange between the propellant and the wall. The model substantially underpredicts the experimental thermal efficiency values. Alternative thruster configurations yielding significant improvements in thrust efficiency and specific impulse are discussed.