Power plants – Combustion products used as motive fluid – Rotating combustion products generator and turbine
Reexamination Certificate
1997-12-16
2002-01-01
Kim, Ted (Department: 3746)
Power plants
Combustion products used as motive fluid
Rotating combustion products generator and turbine
C060S039340
Reexamination Certificate
active
06334299
ABSTRACT:
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
This invention uses ramjet technology for power generation. The fundamentals the technology were set forth in detail in my prior application Ser. No. 07/945,228, filed Sep. 14, 1992, now U.S. Pat. No. 5,372,005, issued Dec. 13, 1994. Certain embodiments were also provided in U.S. patent application Ser. No. 08/480,663, filed Jun. 7, 1995 now U.S. Pat. No. 5,709,076. Specific embodiments were also earlier disclosed in my U.S. Provisional patent application, Ser. No. 60/028,311, filed Dec. 16, 1996. The disclosures of such patent applications, and the issued U.S. patent, all as just identified in this paragraph, are incorporated herein by this reference.
TECHNICAL FIELD OF THE INVENTION
My invention relates to a high efficiency, novel ramjet driven rotary engine, and to a method for the generation of electrical and mechanical power with the engine, while minimizing emission rates of nitrogen oxides. More particularly, my invention relates to a power plant driven by a ramjet engine, and to structures which are designed to withstand the extremely high tensile stress encountered in a rotating device with distally mounted ramjets operating at supersonic speeds. Power plants of that character are particularly useful for generation of electrical and mechanical power.
BACKGROUND OF THE INVENTION
A continuing demand exists for a simple, highly efficient and inexpensive thermal power plant which can reliably provide low cost electrical and mechanical power. This is because many electrical and/or mechanical power plants could substantially benefit from a prime mover that offered a significant improvement over currently practiced cycle efficiencies in power generation. This is particularly true in medium size power plants—largely in the 10 to 100 megawatt range which are used in many industrial applications, including stationary electric power generating units, rail locomotives, marine power systems, and aircraft engines.
Medium sized power plants are also well suited for use in industrial and utility cogeneration facilities. Such facilities are increasingly employed to service thermal power needs while simultaneously generating electrical power at somewhat reduced overall costs. Power plant designs which are now commonly utilized in co-generation applications include (a) gas turbines, driven by the combustion of natural gas, fuel oil, or other fuels, which capture the thermal and kinetic energy from the combustion gases, (b) steam turbines, driven by the steam which is generated in boilers from the combustion of coal, fuel oil, natural gas, solid waste, or other fuels, and (c) large scale reciprocating engines, usually diesel cycle and typically fired with fuel oils.
Of the currently available power plant technologies, diesel fueled reciprocating and advanced aeroderivative turbine engines have the highest efficiency levels. Unfortunately, with respect to the reciprocating engines, at power output levels greater than approximately 1 megawatt, the size of the individual engine components required become almost unmanageably large, and as a result, widespread commercial use of single unit reciprocating engine systems in larger sizes has not been developed. Gas turbines perform more reliably than reciprocating engines, and are therefore frequently employed in plants which have higher power output levels. However, because gas turbines are only moderately efficient in converting fuel to electrical energy, gas turbine powered plants are most effectively employed in co-generation systems where both electrical and thermal energy can be utilized. In that way, the moderate efficiency of a gas turbine can in part be counterbalanced by using the thermal energy to increase the overall cycle efficiency.
Fossil fueled steam turbine electrical power generation systems are also of fairly low efficiency, often in the range of 30% to 40% on an overall net power output to raw fuel value basis. Still, such systems are commonly employed in both utility and industrial applications for base load electrical power generation. This is primarily due to the high reliability of such systems.
In any event, particularly in view of reduced governmental regulation in the sale of electrical power, it can be appreciated that it would be desirable to attain significant cost reduction in electrical power generation. Fundamentally, particularly in view of long term fuel costs, this would be most effectively accomplished by generating electrical power at a higher overall cycle efficiency than is currently known or practiced.
SUMMARY OF THE INVENTION
I have now invented an improved power plant based on the use of a supersonic ramjet thrust module as the prime mover to rotate a power shaft. In using this method to generate electrical power, the supersonic ramjet thrust module is directly or indirectly coupled with an electrical generator. By use of a secondary fuel feed arrangement, the power output of the ramjet thrust module can be turned down as necessary to maintain constant rotating velocity, such as is necessary in synchronous power generation apparatus, at minimal output loads. Throughout its operating range, the supersonic ramjet power plant has greatly increased efficiencies when compared to those heretofore used power plants of which I am aware.
The designs incorporated into my power plant overcomes four significant and serious problems which have plagued earlier attempts at ramjet utilization for efficient electrical power production:
First, at the moderate mach number tip speeds at which my device operates (preferably, Mach 2.5 to about Mach 4.0), the design minimizes aerodynamic drag. This is accomplished by both reducing the effective atmospheric density that the rotor encounters, and by use of a boundary layer control and cooling technique. Thus, the design minimizes parasitic losses to the power plant due to the drag resulting simply from rotational movement of the rotor. This is important commercially because it enables a power plant to avoid large parasitic losses that undesirably consume fuel and reduce overall efficiency.
Second, the selection of materials and the mechanical design of rotating components avoids use of excessive quantities or weights of materials (a vast improvement over large rotating mass designs), and provides the necessary strength, particularly tensile strength where needed in the rotor, to prevent internal separation of the rotor by virtue of the centrifugal forces acting due to the extremely high speed rotor.
Third, the design provides for effective mechanical separation of the cool entering fuel and oxidizer gases from the exiting hot combustion gases, while allowing ramjet operation along a circumferential pathway.
Fourth, the design provides for effective film cooling of rotor rim components, including rim segments, rim strakes, and ramjet thrust modules. This novel design enables the use of lightweight components in the ramjet combustor and in the ramjet hot combustion exhaust gas environment, including potentially combustible components such as titanium.
To solve the above mentioned problems, I have now developed novel rotor designs which overcome the problems inherent in the heretofore known apparatus and methods known to me which have been proposed for the application of ramjet technology to stationary power generation equipment. Of primary importance, I have now developed a low drag rotor which has one or more unshrouded ramjet thrust modules mounted on the distal edge thereof. A number N of peripherially, preferably partially helically extending strakes S partition the entering gas flow sequentially to the inlet to a first one of one or more ramjets, and then to a second one of one or more ramjets, and so on to an Nth one of one
Kim Ted
R. Reams Goodloe, Jr.
Ramgen Power Systems, Inc.
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