Batteries: thermoelectric and photoelectric – Photoelectric – Cells
Reexamination Certificate
2000-01-13
2001-03-06
Diamond, Alan (Department: 1753)
Batteries: thermoelectric and photoelectric
Photoelectric
Cells
C136S291000, C136S205000, C431S100000, C431S115000, C431S116000
Reexamination Certificate
active
06198038
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to logistic-fueled direct energy conversion power sources, such as thermophotovoltaic (TPV), thermoelectric (TE), and alkali-metal-thermal-to-electric-conversion (AMTEC) devices, and is directed more particularly to a burner and a bumer/emitter/recuperator (BER) assembly for use in such power sources.
2. Description of the Prior Art
Two major components of a direct energy conversion power source are (1) a burner/emitter recuperator (BER) assembly, and (2) a power converter assembly (PCA). The objective of the BER is to burn fuel cleanly with the lowest amount of parasitic power consumption and to convert the highest fraction of combustion energy in the fuel to radiant thermal energy. Logistic fuels, as defined by the U.S. military, include diesel (DF-2) and JP-8, and have been preferred inasmuch as they provide the advantages of high energy density and transportability. The PCA converts the radiant thermal energy directly into electrical power through thermophotovoltaics (TPV), thermoelectric (TE), or alkali-metal-thermal-to-electric-conversion (AMTEC).
For small power sources with high system efficiencies, the fuel-firing rate is very low. For instance, a 250 W
e
power source with a system efficiency of 10% (fuel to electric power) has a fuel firing rate of only 0.07 gallons per hour. To achieve 10% or higher efficiency, the combustion air has to be preheated to a temperature of at least 2000° F. The combination of logistic fuel, very low fuel firing rate, and very high air preheat temperature makes the burner design extremely challenging. The conventional pressure-atomized retention head burners cannot be used for such low fuel firing rates because of the extremely small orifice size involved. Other advanced burner designs for low fuel firing rates, such as ultrasonic atomization burners, electrostatic atomization burners, air atomized burners, vaporizing burners, and Babington atomizers have their own unique problems for this application, mostly resulting from extremely high air preheat temperature (about 2000° F.), super high flame temperature (about 4000° F.), or very high combustion chamber temperature (about 3000° F.). For example, the very high temperature of the combustion air causes “coking” of the burner nozzle outlet, i.e. accumulation of fuel residues which, because the orifices are extremely small, leads to blockage of orifices, malfunctioning of the burner, and breakdown of the power assembly.
There is thus a need for a burner and a burner/emitter/recuperator (BER) assembly for power converters, which burner and assembly uses logistic fuel with very high temperature combustion air, produces a high flame temperature, maintains a high combustion temperature, and has the following features:
Does not suffer from fuel coking;
Has smooth ignition without smoke or unburned hydrocarbon emissions;
Provides precise fuel flow regulation;
Can operate at very low ambient temperatures; and
Has low parasitic power requirements.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to provide a burner and BER assembly for direct power conversion devices, which meets the above described requirements.
With the above and other objects in view, as will hereinafter appear, a feature of the present invention is the provision of a burner assembly for supporting a flame in a combustion chamber, the assembly comprising an elongated fuel pipe in communication with a fuel source and extending toward the combustion chamber, and adapted to flow fuel from the fuel source to a nozzle end of the fuel pipe proximate the combustion chamber. The invention further includes a primary air pipe disposed around the fuel pipe and in communication with a relatively cool primary air source, a nozzle end of the primary air pipe being substantially coincident with the nozzle end of the fuel pipe, and a preheated air manifold disposed around a distal portion of the primary air pipe and in communication with a secondary air source. The relatively cool air from the primary air source and fuel from the fuel source flow through the primary air pipe and fuel pipe, respectively, and mix with the hot air from the manifold, exterior to the fuel pipe nozzle end and the primary air pipe nozzle end, to maintain a relatively cool fuel pipe nozzle end, and a relatively hot flame in the combustion chamber.
In accordance with a further feature of the invention, there is provided a burner assembly for supporting a flame in a combustion chamber, the assembly comprising an elongated fuel pipe for flowing fuel from a fuel source to a nozzle end of the fuel pipe proximate the combustion chamber. The assembly further includes a primary air pipe disposed around the fuel pipe and in communication with a relatively cool primary air source, a nozzle end of the primary air pipe being substantially coincident with the nozzle end of the fuel pipe, and a recuperator for preheating secondary air disposed around a distal portion of the primary air pipe and in communication with a secondary air source. The relatively cool air from the primary air source and fuel from the fuel source flow through the primary air pipe and fuel pipe, respectively, and mix with the hot air from the recuperator, exterior to the fuel pipe nozzle end and the primary air pipe nozzle end, to maintain a relatively cool fuel pipe nozzle end, and a relatively hot flame in the combustion chamber.
In accordance with a still further feature of the invention, there is provided a burner/emitter/recuperator (BER) assembly for a direct energy conversion power source, the assembly comprising a burner assembly for supporting a flame in a combustion chamber, the burner assembly comprising a fuel pipe for flowing fuel from a fuel source and extending toward the combustion chamber, a primary air pipe disposed around the fuel pipe and in communication with a relatively cool primary air source, a nozzle end of the primary air pipe being substantially coincident with a nozzle end of the fuel pipe, and a secondary air manifold disposed around the primary air pipe and in communication with a secondary air source, the secondary air manifold being adapted to flow secondary air to the nozzle ends. The BER further comprises a recuperator assembly comprising an annular channel extending from the combustion chamber and defined in part by the manifold, and adapted to flow combustion gases along a surface of the manifold to impart heat thereto and to the secondary air therein, and an emitter disposed around the combustion chamber, the emitter being adapted to be heated by a flame in the combustion chamber and to radiate thermal heat for conversion to electrical power.
The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.
REFERENCES:
patent: 2224544 (1940-12-01), Keller
patent: 4023921 (1977-05-01), Anson
patent: 4707560 (1987-11-01), Hotteletal
patent: 5312521 (1994-05-01), Fraas et al.
patent: 5439532 (1995-08-01), Fraas
patent: 5512109 (1996-04-01), Fraas et al.
patent: 5651838 (1997-07-01), Fraas et al.
patent: 5711661 (1998-01-01), Kushch et al.
patent: 5932885 (1999-08-01), DeBellis et al.
Kittl et al, 25th Annual Proceedings Power Sources Conference, May 1972.
Doyle Edward F.
Metcalfe Christopher I.
Shukla Kailash C.
Diamond Alan
Pandiscio & Pandiscio
Thermo Power Corporation
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