Olin Corporation

Mark A Simon

William W Smith

Steve Knowles

Richard Dale Smith

R J Cassady

George W Butler

An arcjet thruster is disclosed which has an electrically conductive anode body having an anode cavity therein which defines a nozzle symmetrical about a central axis. The anode cavity has a tandemly arranged divergent recombination portion and a divergent expansion portion. The expansion portion has a greater rate of divergence than the recombination portion. The anode body further preferably comprises a cylindrical constrictor portion upstream and in tandem with the recombination portion. An electrically conductive cylindrical cathode body is coaxially arranged and spaced from the anode body by a gap. An electrical current source connected to the cathode and the anode produces an electrical arc across the gap. A vortex flow of propellant gas is fed through the gap and through the nozzle to produce thrust. The vortex flow of propellant gas pushes the arc through the constrictor into one of the divergent portions of the nozzle. The recombination and expansion portions merge at a transition being between a divergence of 5 and 15 degrees and within a diameter ratio range of the transition to the constrictor of about 1.5 to 4.0. The divergent recombination portion causes a portion of the ionized and disassociated propellant gas passing therethrough to recombine, recovering frozen flow losses prior to entering the expansion portion and increasing the overall energy conversion efficiency of the thruster.

Arcjet nozzle having improved electrical-to-thrust conversion efficiency

An arcjet thruster has a body defining a constrictor and nozzle constituting an anode and forming an arc chamber. An elongated rod constitutes a cathode spaced from the constrictor by a gap generally coextensive with the arc chamber. An electrical potential is applied to the anode and cathode to generate an electrical arc in the arc chamber from the cathode to the anode. Propellant is supplied to the arc chamber with generation of the arc so as to produce thermal heating and expansion of the propellant through the nozzle. The thruster employs several features which improve its performance. One feature relates to the use of propellant blends with high specific impulse additives. Another feature relates to injection of the high specific impulse additive into the bulk propellant feed at the region of the cathode tip. Still another feature relates to recirculation of a small fraction of propellant from the constrictor region of the arc chamber and injection thereof into the bulk propellant feed at the region of the cathode tip. A final feature relates to regeneration and reaction of the bulk propellant feed within the structure of the anode body and circulation to the region of the cathode tip.

Performance arcjet thruster

An arcjet thruster has an anode body forming a constrictor and a nozzle which define an arc chamber. The thruster also has a cathode in the form of a rod having a tip and being spaced upstream from the constrictor. The thruster employs several features which reduce anode and cathode erosion and increase the operational life of the thruster. One set of features relate to the employment of cathode and anode shaping. Another feature relates to the use of a propellant injector having a series of radially and tangentially arranged passages for providing direct injection of propellant gas into the arc chamber and enhanced convective cooling of the anode.

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Redmond, WA, United States of America

Mark A Simon