Power plants – Combustion products used as motive fluid – Combustion products generator
Reexamination Certificate
2000-03-02
2002-08-13
Koczo, Michael (Department: 3746)
Power plants
Combustion products used as motive fluid
Combustion products generator
C060S247000, C060S746000
Reexamination Certificate
active
06430919
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to pulsed hypersonic compression waves and more particularly to shaped charge devices using pulsed hypersonic compression waves to create thrust.
BACKGROUND OF THE INVENTION
In propulsion devices such as jet engines and rocket engines, propulsion thrust is obtained by high-speed exhaust flows. Conventional jet engines obtain the high-speed exhaust by combustion products of fuel and air, while rocket engines obtain the high-speed exhaust by internal combustion products of fuel and oxidizer. The high pressure combustion products are forced through a restrictive orifice, or nozzle, to obtain the high-speed exhaust flow.
Several problems are inherent in the conventional systems. The combustion in both jet and rocket engines must contain extremely high internal pressures and are therefore limited by construction material strength. As the internal combustion pressure increases, the combustion chamber wall must increase in thickness to contain the pressure, increasing the combustion chamber weight proportionally and limiting the design. Also, as the exhaust nozzle diameter is reduced to increase exhaust speed, cooling the engine and nozzle becomes increasingly more difficult. In addition, pulsed engines are unable to evacuate the combustion products in a short time moment, thus limiting the firing speed.
Furthermore, as internal pressure in the combustion chamber increases, higher fuel and oxidizer inlet pressures are required to introduce fuel and oxidizer into the combustion chamber, requiring heavier weight pumps that operate at higher horsepower. One example of such limitations on present engines is seen in the phase two main space shuttle engine. The engine requires 108,400 horsepower to drive the fuel and oxidizer pumps alone. Inlet pressures exceed 6,800 psi in order to obtain an internal combustion chamber pressure to only 3,260 psi with a combustion chamber to nozzle ratio of 77 to 1.
The huge plume of fire trailing the shuttle and other rockets is caused by incomplete combustion of the fuel and oxidizer prior to exiting the exhaust nozzle. The fuel and oxidizer igniting outside the engine provide virtually no thrust and are thus wasted. The above space shuttle engine example requires 2,000 pounds of fuel and oxidizer per second to obtain 418,000 pounds thrust at sea level. Furthermore, the continuous ignition of present engines causes high heat transfer to engine parts, particularly the nozzle orifice, and the high heat transfer requires the use of costly exotic materials and intricate cooling schemes to preserve the engine structure.
Prior efforts to improve the engine design focus on various components, including the nozzle. For example, U.S. Pat. No. 6,003,301 to Bratkovich et al., entitled “Exhaust Nozzle for Multi-Tube Detonative Engines” teaches the use of a nozzle in an engine having multiple combustor tubes and a common plenum communicating with the combustor tubes. Accordingly, Bratkovich et al. teach that the common plenum and a compound flow throat cooperate to maintain a predetermined upstream combustor pressure regardless of downstream pressure exiting the expansion section.
While the prior art addresses many aspects of propulsion devices, it does not teach the use of a shaped charge in a jet or rocket engine. A shaped charge is generally defined as a charge that is shaped in a manner that concentrates its explosive force in a particular direction. While the general theory behind shaped charges has been known for many years, the prior art has restricted the use of shaped charges to warheads and certain other expendable detonation devices. In a typical warhead, the shaped charge directs its explosive forces forwardly, in the direction the warhead is traveling, by igniting moments before or substantially simultaneously with impact. The highly concentrated force can be used to create a cheap, lightweight armor-piercing device. Examples of shaped charge devices are described in U.S. Pat. No. 5,275,355 to Grosswendt, et al., entitled “Antitank Weapon For Combating a Tank From The Top,” and U.S. Pat. No. 5,363,766 to Brandon, et al., entitled, “Ramjet Powered, Armor Piercing, High Explosive Projectile.” Shaped charges in such devices are not used to provide propulsion.
Similarly, current engines configured to drive a turbine do not employ shaped charge engines. One example of a pulsed turbine engine is disclosed in U.S. Pat. No. 6,000,214 to Scragg, entitled “Detonation Cycle Gas Turbine Engine System Having Intermittent Fuel and Air Delivery.” Scragg teaches a detonation cycle gas turbine engine including a turbine rotor within a housing. Valveless combustion chambers are positioned on either side of the rotor to direct combustion gases toward the turbine blades. The two combustion chambers alternately ignite the mixture of fuel and oxidizer to cyclically drive the turbine. While Scragg discloses a useful engine, efficiency, horsepower per unit of engine weight, and other performance parameters could be greatly improved. For example, the Scragg device constructed to deliver 200 hp would require a 560 cubic inch combustion chamber and would weigh 262 pounds, while a 200 hp engine using a shaped charge as in the present invention would require a combustion chamber of only 18 cubic inches and would weigh only 70 lbs.
There is therefore a need for a shaped charge propulsion device that provides substantially improved performance than prior art devices.
SUMMARY OF THE INVENTION
The present invention provides a shaped charge engine that overcomes many limitations of the prior art. The apparatus includes a blast-forming chamber comprising an inner annular charge forming housing having a conical convex projection that forms the inner walls of the blast-forming chamber. A central through hole is provided to allow exhaust gases to exit. An outer housing comprises a generally round disk with an inner conical concave depression and through holes for the insertion of fuel and ignition. The two housings are joined by conventional means such as welding or bolts. The resulting chamber formed by joining the two housings is taper-conical in shape, wider at the base, and gradually decreasing in cross-sectional area as it rises to the apex. This construction forms a circular pinch point or throat toward the apex that forms the primary or first stage compression area. A secondary compression zone is created at the apex of the outer housing, just beyond the throat. Hypersonic gases exit the through hole in the inner housing.
In accordance with further aspects of the invention, a directed thrust is formed in a pulsed manner using a contained burn that starts at a peripheral base area and is directed in a tapered-conical shape that forms a primary compression area adjacent the apex of the conical shape. The compressed burn thereafter continues to the apex of the tapered-conical shape, creating a high-speed convergence or secondary compression zone before being exhausted. This construction provides a more complete ignition within the chamber, enhancing efficiency by capturing more of the energy before it leaves the engine. It also allows for the combustion products to exit the primary combustion chamber more rapidly, thus allowing a higher pulse rate of firing while maintaining the high compression exhaust flows by not compressing exhaust products to final velocity internally.
In accordance with other aspects of the invention, the engine includes a sensor to determine the ambient air density, allowing the engine to selectively consume air or oxidizers, as appropriate.
In accordance with still further aspects of the invention, inexpensive conventional fuels, such as gasoline, acetylene, butane, propane, natural gas, and diesel oil are mixed with air or an oxidizer into a combustible mixture and infused under positive pressure into the hollow blast-forming chamber in a manner that permits positive shutoff between a series of induction cycles to accommodate ignition cycles.
In accordance with yet other aspects of the invention, an igniter i
Black Lowe & Graham PLLC
Direct Propulsion Devices, Inc.
Koczo Michael
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