Patent Application
20110107763
The present disclosure relates to a self-sustaining co-generator which utilizes a micro gas turbine engine to provide heated air through a heat exchanger, catalyst or direct fire and for generating rotary drive which can power an auxiliary generator, and more particularly to an improved fuel deflector/slinger assembly for the micro gas turbine engine which minimizes particle build-up in the fuel delivery system.
This section provides background information related to the present disclosure which is not necessarily prior art.
Recent efforts have shown that micro gas turbine engines can be useful in co-generation applications to provide heat and auxiliary electrical power. In particular, the small gas turbine has proven to be light, relatively trouble free and extremely efficient such that it makes an excellent heater. Exemplary embodiments of a co-generator utilizing a micro gas turbine engine are the subject of U.S. Pat. No. 6,073,857, U.S. Pat. No. 6,161,768 and U.S. Pat. No. 6,679,433 by Gordon et al.
These embodiments disclosed by Gordon et al. featured fuel entering the rear housing via a fuel delivery tube; where a minor amount of heat is added. The fuel delivered in the rear housing through drilled holes enters a delivery space between two Belleville springs. Hot air is also introduced at this site, and the fuel-air mixture is fed into the bearing, cooling and lubricating the bearing. Some fuel flows around the bearing flooding the spring suspension system, all the while picking up heat. The mixture then enters a slinger plenum chamber defined by a rotating slinger body and a stationary fuel deflector tube. Additional hot air from the combustion chamber is added before the fuel-air mixture enters the slinger impeller which adds more heat and injects it into the combustion chamber.
With this configuration, fuel delivery is adequate and a blue flame or non-visible flame is produced in the combustion chamber with moderately cold ambient temperatures such as those experienced in the northern states of the continental United States. However, extremely cold ambient temperatures such as those experienced in Canada and Alaska changes the stoichiometry of combustion which presents complication factors. It was known that a fuel heater may be employed to thermally condition the fuel and it was known to insulate the annulus between the combustor and the engine housing to maintain a more consistent operating temperature in the combustion chamber.
During prolonged operation in extreme conditions, it has been observed that carbon deposits can form in the fuel deflector, slinger body and slinger assembly and could not be eliminated. Conventional solutions to this problem were ineffective for eliminating these deposits, eventually leading to blockages in the fuel delivery system. Accordingly, there is a need in the art to provide a fuel delivery system in a mirco gas turbine engine that provides adequate fuel flow and thermal condition without developing excessive carbon deposits resulting in fuel blockage build-up.
This section provides a general summary of the disclosure, but is not a comprehensive disclosure of its full scope or all of its features.
An improved micro gas turbine engine, and in particular an improved fuel deflector/slinger assembly are the subject of this patent disclosure. As described above, the mixture entering the fuel deflector, includes air, liquid fuel, and vaporized fuel extending into possibly a fuel plasma which essentially constitutes a complete range of heated partially combusted fuel. In order to minimize particle buildup within the fuel delivery system, the inner surface of the fuel deflector is contoured with an undulation that reduces deposits to near zero. The specific dimensions of the surface contouring is a function of the fuel preparation for which the fuel temperature, velocity and the amount of mechanical mixing which would be similar regardless of the heaters size, and thus is readily scalable to a gas turbine engines having a range of displacement.
An improved slinger impeller is also the subject of this patent disclosure. In particular, the improved slinger impeller features completely round channels eliminating corners and pockets where deposits can readily form. The channels are formed by drilling tapered holes around the impeller diameter. The improved impeller also features less back sweep than previous impellers.
In addition, a radial deflector ring having multiple short triangular blades is positioned upstream of the impeller. The deflector ring facilitates flow from the channel bounded by the fuel deflector tube into the inducer and then into the impeller. The deflector ring also mixes and impacts the fuel, air, and combustion products mixture to a final near uniform product, further reducing the tendency for deposits formation.
Further scope of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings. These example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Various specific details are set forth such as examples of components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
With reference now to
Turbo heater 10 is a diesel fueled self-contained and self-sustaining heating system for supplying heated air and electrical power in remote locations. Gas turbine engine 12 is designed to supply the majority of its energy as heat in the form of exhaust gases, and a minor amount as shaft power used to drive the axial fan 26 and other auxiliary power generation mechanisms.
Turbo heater 10 is designed to feature economical construction and is especially designed for reduced manufacturing cost. The internal aerodynamics, such as the turbine and compressor wheels, use well-developed turbocharger technology. For example, the preferred flow and pressure ratios are nearly optimum for automotive turbocharger components, and are thus near-optimum for use in the turbo heater 10. A peak cycle temperature of 1500° Fahrenheit (° F.) is preferred to allow the use of economical materials for the high temperature components.
With continued reference to
Alternately, an air-to-air heat exchangers, an air-to-liquid heat exchanger, a liquid coil or a combination thereof may be used to generate heated air, heated liquid or both. Similarly, in some applications where human consumption of the heated air is not a requirement, a heat exchanger or catalytic converter may not be required such that the exhaust gas directly from the gas turbine engine 12 is mixed with fresh air from the axial fan 26 to produce a heated mixture of exhaust gases and air.
The turbo heater 10 is self-contained and nearly instantaneously starting, and will operate at a minimum heat output on a reasonable on-off cycle for lower heat requirements. Operation of the turbo heater 10 in this manner can provide an environment of uniform heat, using the minimum fuel necessary. As such, the turbo heater 10 is an ideal source of heated air as it can supply a large quantity of heat at relatively low ambient temperatures. For example, while nominally rated at 500,000 Btu/hr, the turbo heater 10 can be modulated from less than 250,000 Btu/hr to greater than 750,000 Btu/hr at an ambient temperature of minus 50° F.
Further details concerning the components and operation of the turbo heater 10 and the gas turbine engine 12 are set forth in U.S. Pat. No. 6,073,857, U.S. Pat. No. 6,161,768 and U.S. Pat. No. 6,679,433 to Gordon et al. The entire disclosure of each of the above patents is incorporated herein by reference.
Referring now to
With reference to
The fuel-air mixtures passes through the rear bearing assembly 50 and passes into fuel delivery channel 94. The fuel delivery channel 94 is diverging with respect to the longitudinal axis of the center shaft assembly 40 and is defined between fuel slinger assembly 46 and fuel deflector 96. As can be seen in
As best shown in
As previously mentioned, the mixture entering the fuel deflector 96, is air, liquid fuel, vaporized fuel extending into possibly a plasma, essentially a complete range of heated partially combusted fuel which can result in a slow particle build-up over time to the point of creating a blockage in the fuel delivery path. As best shown in
The fuel-air mixture being discharged from the fuel delivery channel 94 enters the slinger assembly 46, along with additional air entrained from the combustor 20. The air-fuel mixture is combusted and exhaust through turbine 22 which in turn drives compressor 18 via shaft assembly 24.
One skilled in the art will recognized that the turbo heater 10 may be provided with an engine controller and various sensors to monitor and control engine operating parameters, an ignition system for initiating combustion, an electric fuel pump that pumps fuel to fuel passageway 78, 86 formed in gas turbine engine 12, and a starting system with a starter motor which is adequately sized to insure adequate power to start the gas turbine engine 12 during very cold weather. The details of these components, as well as operation of the turbo heater 10 are set forth in the patents to Gordon et al. previously incorporated by reference herein.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.
