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US 4,907,407 AGranted
Lifetime arcjet thruster
AssigneeOlin Corporation
InventorsMark A. Simon, Steve Knowles, William Smith
Life of this patent
Estimating the term…
Abstract
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.
Claims27
In an arcjet thruster, the combination comprising:
- (a) an electrically-conductive anode body having oppositely-tapered upstream and downstream interior conical surfaces about a common axis, said downstream interior conical surface defining a nozzle having tandemly-arranged upstream throat and downstream expansion regions which together define an arc chamber of generally nonparallel supersonic configuration, said upstream and downstream interior conical surfaces merging at a location of minimum diameter which defines said upstream throat of said nozzle;
- (b) an elongated electrically-conductive cathode member having a tip disposed adjacent to said upstream interior conical surface of said anode body and spaced upstream from said nozzle throat region by a gap;
- (c) means for applying an electrical potential to said anode body and cathode member so as to generate an electrical arc in said arc chamber extending from said cathode member tip to said anode body which due to location of said nozzle throat region and supersonic configuration of said nozzle attaches to said anode body at a location downstream of said nozzle throat region;
- and
- (d) means for supplying a flowing propellant gas radially and tangentially into said arc chamber through said nozzle throat region at about sonic velocity concurrently with the generation of said arc so as to cause said arc to attach to said anode at a location downstream of said nozzle throat region and produce thermal heating of said flowing gas in said chamber and expansion thereof through said nozzle expansion region.
2 more elements
In an arcjet thruster, the combination comprising:
- (a) an electrically-conductive anode body having an upstream end portion and a downstream portion, said anode body forming a nozzle having tandemly-arranged upstream throat and downstream expansion regions together defining an arc chamber, said throat region being a location of minimum diameter;
- (b) an elongated electrically-conductive cathode member having a tip disposed adjacent to and spaced upstream from said throat region of said nozzle by a gap;
- (c) means for applying an electrical potential to said anode body and cathode member so as to generate an electrical arc in said arc chamber extending from said cathode member tip to said anode body which in steady state attaches to said anode body at a location downstream of said nozzle throat region;
- (d) said tip of said cathode member having an indented region within which steady state attachment of said arc resides so as to reduce erosion of said cathode tip;
- and
- (e) means for supplying a flowing propellant gas radially and tangentially into and through said nozzle throat region at about sonic velocity concurrently with the generation of said arc so as to produce thermal heating of said flowing gas in said chamber and expansion thereof through said nozzle expansion region, said gas having a subsonic velocity upstream of said throat region and a supersonic velocity in at least a portion of said expansion region.
3 more elements
In an arcjet thruster, the combination comprising:
- (a) an electrically-conductive anode body including a nozzle having tandemly-arranged upstream throat and downstream expansion regions and defining an arc chamber, said upstream throat region being a location of minimum diameter;
- (b) an elongated electrically-conductive cathode member having a tip disposed adjacent to and spaced upstream from said throat region of said nozzle by a gap;
- (c) means for applying an electrical potential to said anode body and cathode member so as to generate an electrical arc in said arc chamber extending from said cathode member tip to said anode body which in steady state attaches to said anode body at a location downstream of said nozzle throat region;
- and
- (d) means for supplying a flowing propellant gas directly into said arc chamber radially and tangentially into and through said nozzle throat region at about sonic velocity concurrently with the generation of said arc without first passing said flowing gas along the length of said cathode member so as to produce thermal heating of said flowing gas in said chamber and expansion thereof through said nozzle expansion region.
2 more elements
Dependencies are inferred from the claim text.