Solid fuel ducted rocket with gel-oxidizer augmentation propulsion

• US 5,152,136 A
• Filed: 08/05/1991
• Issued: 10/06/1992
• Est. Priority Date: 08/05/1991
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Lilley, Jay S., May, Douglas L., Asaoka, Leo K., Chew, William M.
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): RICHMAN, HOWARD
• Application Number:
  US07/741,296
• Time in Patent Office: 428 Days
• Field of Search: 60/251, 60/252, 60/253, 60/245, 60/270.1
• US Class Current: 60/251
• CPC Class Codes: F02K 7/18 Composite ram-jet/rocket engines
• CPC Class Codes: F02K 9/08 using solid propellants F02K9/72 takes precedence; using semi-solid or pulverulent propellants F02K9/70
• CPC Class Codes: F02K 9/72 using liquid and solid propellants, i.e. hybrid rocket-engine plants

Abstract

A propulsion system is disclosed comprising a glycidyl azide polymer (GAP)olid fuel generator (SFGG) that produces fuel-rich hot gases which are combusted in a combustion zone of a combustion chamber of a solid fuel ducted rocket. A basic embodiment comprises an airbreathing engine wherein a ducted member scoops air in from the atmosphere for hypergolic reaction with the fuel-rich hot gases for propulsion during a sustain stage of a flight. An augmentation of the basic embodiment is achieved by combusting the fuel-rich GAP SFGG effluent with inhibited red fuming nitric acid (IRFNA) gel oxidizer to produce higher thrust during the boost and dash stages of a flight. During the high thrust stages, the air ducts of the ducted member are closed and IRFNA gel is injected into the combustion chamber to react with the fuel-rich hot gases from the GAP SFGG. The resulting higher pressure in the combustion chamber gives the missile a correspondingly greater thrust than during the lower pressure airbreathing sustain stage of flight.

Claims

1. A solid fuel ducted rocket augmented with gel-oxidizer comprising:

(i) a rocket motor case having a head-end and an aft end;

(ii) an exhaust nozzle secured to said rocket motor case at the aft-end thereof;

(iii) a combustion zone of a combustion chamber within said rocket motor case and in communication with said exhaust nozzle, said combustion zone being a zone in the combustion chamber wherein fuel and oxidizer are brought together for hypergolic reaction;

(iv) a glycidyl azide polymer solid fuel gas generator installed within said rocket motor case at the head-end thereof, said glycidyl azide polymer after being ignited performing the function of supplying fuel-rich hot gases for further combustion within said rocket motor case in a combustion zone of a combustion chamber;

(v) an igniter for igniting said glycidyl azide polymer;

(vi) a ducted member extending outwardly from said rocket motor case between said aft-end and said head-end thereof and forming an air scoop having an air inlet for directing air scooped from the atmosphere during a low pressure airbreathing sustain stage of a flight into the interior of said rocket motor case for combustion of said fuel-rich hot gases in a combustion zone of a combustion chamber;

(vii) a moveable intake closure mounted within said combustion chamber, said intake closure capable of being opened during a sustain stage of flight to allow air to be scooped into said combustion chamber and said intake closure capable of being closed during a boost or dash stage of flight to minimize drag and to retain higher combustion pressure within said combustion chamber, as compared with said sustain stage of flight, employing said gel-oxidizer for hypergolic reaction with said fuel-rich hot gases;

(viii) a housing structure in a spaced apart relationship from said glycidyl azide polymer within said rocket motor case and extending toward the aft-end of said rocket motor case, said housing structure in said spaced apart relationship defining a combustion zone and one or more conduits for conducting fuel-rich hot gases into said combustion zone for hypergolic reaction with air scooped in during a lower pressure airbreathing sustain stage of propulsion and said housing structure having a storage capability for storing a gel-oxidizer and means for expelling said gel-oxidizer for hypergolic reaction with said fuel-rich hot gases at a much higher pressure during a boost or dash stage of a flight as compared with said sustain stage of a flight;

(ix) a combustion zone of a combustion chamber within said rocket motor case defined by an outer surface of housing structure extending toward said aft-end of said rocket motor case, said combustion zone being a zone of a combustion chamber for hypergolic reaction during said sustain, boost, and dash stages of flight with said fuel-rich hot gases, to produce combustion gases for exhausting through said exhaust nozzle to produce thrust; and

,

(x) a fuel insulation layer installed on an internal surface of said rocket motor case, said fuel insulating layer performing a dual function of insulating said rocket motor case and supplying gaseous combustible products for combustion within said combustion zone of said combustion chamber.

2. The solid fuel ducted rocket augmented with gel-oxidizer as defined in claim 1 wherein said one or more conduits for said fuel-rich hot gases additionally comprise a high pressure burst disk installed in each of said conduits which after being ruptured by pressure exerted by said fuel-rich hot gases allows said fuel-rich hot gases to be discharged into said combustion zone.

3. The solid fuel ducted rocket augmented with gel-oxidizer as defined in claim 2 wherein said housing structure contains a gel-oxidizer of inhibited red fuming nitric acid and wherein said means for expelling said gel-oxidizer comprises a valve control for opening valve means to achieve flow of said gel-oxidizer through said burst disk which ruptures in response to pressure by said gel-oxidizer, said pressure by said gel-oxidizer in response to pressure exerted by said fuel-rich hot gases in an expulsion diaphragm to subsequently expel said gel-oxidizer through an injector into said combustion zone, said combustion zone of a combustion chamber having said intake closure that is in a closed position to thereby achieve hypergolic reaction between said fuel-rich hot gases and said gel-oxidizer to produce a higher combustion zone pressure and higher thrust values during a boost or dash stage of a flight as compared with said sustain stage of flight.