Constant thrust hybrid rocket motor

• US 4,424,679 A
• Filed: 09/10/1981
• Issued: 01/10/1984
• Est. Priority Date: 09/10/1981
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Holzman, Allen L.
• Primary Examiner(s): Croyle, Carlton R.
• Assistant Examiner(s): Simenauer, Jeffrey A.
• Application Number:
  US06/300,766
• Time in Patent Office: 852 Days
• Field of Search: 60/251, 60/254, 60/258, 60/240, 137/110, 137/599, 251/117, 251/139, 251/65
• US Class Current: 60/251
• CPC Class Codes: F02K 9/58 Propellant feed valves
• CPC Class Codes: F02K 9/72 using liquid and solid propellants, i.e. hybrid rocket-engine plants

Abstract

A constant thrust hybrid rocket motor having a valve assembly therein which utilizes a fixed diameter orifice in combination with a valve having a variable sized opening therein in order to provide a regulated flow of oxidizer to the combustion chamber of the rocket motor. By selecting the size of the fixed diameter orifice such that it is slightly less than required to yield oxidizer flow at highest density oxidizer conditions (lowest temperature) and selecting the size of the combination of the fixed orifice and the open position of the variable opening such that it is slightly greater than required at lowest density oxidizer conditions (highest temperature), the operation of the rocket motor can be reliably maintained over a wide temperature range and without experiencing wide pressure variations by regulating the size of the variable opening.

Claims

1. A constant thrust hybrid rocket motor comprising:

a combustion chamber at one end thereof;

an oxidizer source at the other end thereof;

means interconnecting said combustion chamber and said oxidizer source for permitting an oxidizer to flow into said combustion chamber;

means operably connected to said flow permitting means for controlling the flow of said oxidizer therethrough, said flow controlling means including means for allowing a constant flow therethrough and means for allowing a variable flow therethrough, said constant flow control means being in the form of a by-pass line circumventing said variable flow control means, said by-pass line having a fixed diameter orifice of predetermined size, said variable flow control means being in the form of a solenoid valve having an opening which is operable from a closed position to an open position of predetermined size, said predetermined size of said fixed diameter orifice being of substantially such size as to yield required oxidizer flow to said combustion chamber at highest density oxidizer conditions and said predetermined size of said open position of said opening of said solenoid valve in combination with said predetermined size of said fixed orifice being of substantially such size as to yield required oxidizer flow to said combustion chamber at lowest density oxidizer conditions; and

means operably connected to said flow permitting means for monitoring said flow therethrough and providing a signal indicative thereof to said flow controlling means for regulating said variable flow control means;

whereby appropriate regulation of said variable flow control means in combination with said constant flow control means enables operation of said hybrid rocket motor to take place over a wide temperature range and without experiencing wide pressure variations.

2. A constant thrust hybrid rocket motor comprising:

a combustion chamber at one end thereof;

an oxidizer source at the other end thereof;

means interconnecting said combustion chamber and said oxidizer source for permitting an oxidizer to flow into said combustion chamber;

means operably connected to said flow permitting means for controlling the flow of said oxidizer therethrough, said flow controlling means including means for allowing a constant flow therethrough and means for allowing a variable flow therethrough, said constant flow control means and said variable control means of said flow controlling means being part of a single valve, said valve including a housing, said housing having a longitudinally extending passageway therein defining an inlet at one end thereof and an outlet at the other end thereof, and means within said passageway for containing said constant flow control means and said variable control means therein, said constant flow control means being in the form of a fixed diameter orifice of predetermined size adjacent said outlet and said variable control means being in the form of at least one opening and means operably associated with said opening for varying the size of said opening from the closed position to an open position of predetermined size, said predetermined size of said fixed diameter orifice being of substantially such size as to yield required oridizer flow to said combustion chamber at highest density oxidizer conditions and said predetermined size of said open position of said opening in combination with said predetermined size of said fixed orifice being of substantially such size as to yield required oxidizer flow to said combustion chamber at lowest density oxidizer conditions; and

means operably connected to said flow permitting means for monitoring said flow therethrough and providing a signal indicative thereof to said flow controlling means for regulating said variable flow control means;

whereby appropriate regulation of said variable flow control means in combination with said constant flow control means enables operation of said hybrid rocket motor to take place over a wide temperature range and without experiencing wide pressure variations.