Power plants – Reaction motor – Rotating or cyclic movement during axial thrust
Reexamination Certificate
1999-05-14
2001-04-10
Freay, Charles G. (Department: 3746)
Power plants
Reaction motor
Rotating or cyclic movement during axial thrust
C060S211000
Reexamination Certificate
active
06212876
ABSTRACT:
FIELD
The present invention relates to high-efficiency, low complexity, chemical, liquid-fueled rocket propulsion systems.
BACKGROUND
One characterization of the efficiency of a rocket propelled vehicle, particularly one having a chemical propulsion system, is the mass ratio MR of the vehicle defined as the final mass of the vehicle (after propellants are consumed) over the initial mass of the vehicle (before propellants are consumed). The higher the MR, the more total vehicle and payload mass are carried by a unit of propellant, and the less propellant is used merely to carry later-consumed propellant. For a given MR, the proportion of the final vehicle mass available for payload may be increased by weight reduction techniques in the non-payload components, such as use of composite materials and the like.
MR itself can be improved by staging, which allows portions of the system no longer useful to be discarded so that later stages accelerate a smaller total mass. Staging adds significantly to the complexity of a propulsion system, however.
MR may also be improved by increasing the specific impulse (I
SP
) of a propulsion system, with I
SP
defined as the pounds of thrust divided by the mass flow rate in pounds per second of propellant exhaust flowing from the engine of the system, or as the seconds of pounds of thrust per pound of propellant materials. MR increases exponentially as a function of I
SP
. Simply put, the longer and larger the thrust provided from a given weight of propellant, the more propellant energy is available to accelerate the payload and other system components. The lsp of a system can be improved in various ways, including increasing the exhaust velocity of the system such as by increasing the reaction temperature and/or pressure, and increasing the completeness of the reaction of the propellant substance(s). All such improvements should be achieved with minimum added weight, however, or even with weight reduction, if possible.
Liquid fueled rocket propulsion systems generally require some means of delivering propellant to a thrust chamber under pressure. Stored pressurized gas may be used to drive propellant to the thrust chamber (known as a “blowdown system”), but the storage and handling systems for the gas take up valuable space and weight allotments. The required mass of the propellant tankage is proportional to the pressure applied to the propellant, which must exceed the chamber pressure of the engine. Since high chamber pressures are required for maximum I
SP
, such systems are penalized by the increased tankage mass. One or more pumps may be used to pressurize the propellant, but weight must be minimized and efficiency maximized. Such pumps require energy, in most advanced engines this is provided by turbines powered by the fuel and oxidizer, through combustion or as a byproduct of heating through regenerative cooling.
Rocket propulsion systems that are intended to operate continuously for significant lengths of time further require cooling of the combustion chamber and thrust nozzle. Such cooling should be performed as efficiently as possible with a minimum consumption of energy and/or propellant.
SUMMARY
The present invention provides a greatly simplified, efficient liquid-fueled rocket propulsion system. The system includes a rocket engine having a rotor assembly with an ultracentrifugal (over 200 meters/second tangential velocity) liquid pump arranged around a combustion chamber so as to provide both forced convective and Coriolis-effect and centripetal-acceleration enhanced free convective regenerative cooling to the combustion chamber while pressurizing the liquid propellant. Both fuel and oxidizer may be stored at cryogenic temperatures and pumped around the combustion chamber for regenerative cooling. The combustion chamber may be structured to rotate together with the pump to provide Coriolis-effect and centripetal-acceleration enhanced combustion. The rotor assembly is driven directly by a tangential component of the primary thrust vector by means of tilted nozzles or by vanes, flutes or other reaction surfaces. Liquid oxygen and liquid propane, liquid methane or another thermally compatible fuel, maintained at about the same temperature and pressure, may be used as both propellant and coolant, and may be stored in polyethylene terephthalate (PET) or other polymer tankage. The rotor assembly may be the only moving part of the engine, and may comprise the combined functionality of combustion chamber, turbine, pump, and cooling channels, and may desirably be rotated at the highest possible speed to obtain the highest feasible pressures.
This engine is desirably of the plug or aerospike variety, and can be combined with a conventional bell nozzle of various geometries to give proper expansion ratios for the exhaust gasses.
REFERENCES:
patent: 2516462 (1950-07-01), Goddard
patent: 2519878 (1950-08-01), Bjork et al.
patent: 2523011 (1950-09-01), Goddard
patent: 2536599 (1951-01-01), Goddard
patent: 3553964 (1971-01-01), Hircher III
Bowery James Allen
Gregory Roger Everett
Freay Charles G.
Klarquist Sparkman Campbell & Leigh & Whinston, LLP
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