Ignition methods and apparatus using microwave and laser energy

#This invention is related to the following co-pending and/or issued U.S. Patent applications: Ser. No. 081,732, filed Jun. 3, 1993, U.S. Pat. No. 5,367,869, issued Nov. 29, 1994, entitled "Laser Ignition Methods And Apparatus For Combustors"(1930022); Ser. No. 08/067,652, filed May 26, 1993, U.S. Pat. No. 5,515,681, issued May 14, 1996, entitled "Ignition Methods And Apparatus For Combustors"(1930012); Ser. No. 08/463,614, filed Jun. 5, 1995, U.S. Pat. No. 5,673,554, issued Oct. 7, 1997, entitled "Ignition Methods And Apparatus Using Microwave Energy"(1950012); and Ser. No. 08/463,834, filed Jun. 5, 1995, U.S. Pat. No. 5,689,949,issued Nov. 25 ,1997, entitled "Ignition Methods And Apparatus Using Microwave Energy"(1950013); the entire disclosures of which are all fully incorporated herein by reference.

#The invention relates generally to igniting combustible material in a combustor. More particularly, the invention relates to ignition methods and apparatus for combustors using microwave and laser energy.

#A combustor is a fundamental assembly used to confine combustion of a fuel within an engine. For turbine engines, such as for example gas turbine aircraft engines, the combustor typically includes an open ended can or other annular casing that forms part or all of a combustion chamber for the fuel. A single engine may include a number of can combustors, or a single annular combustor, for example. Engines may also include combustors such as preburners and afterburners. Other engine types of interest include rotary engines, reciprocating engines such as, for example, automotive applications, rocket engines, ram jet engines and pulse jet engines.

#FIG. 1 is a simplified block diagram in schematic form of the basic elements or building blocks of an embodiment of the invention;

#FIG. 2 is a schematic diagram in partial section of a gas turbine engine combustor with the invention incorporated therein;

#FIG. 3 is a detailed schematic of a mounting assembly for a wave guide to a combustor as in FIG. 2;

#With reference to FIG. 1, an embodiment of the invention is illustrated in simplified schematic form for purposes of describing the basic concepts of the invention. In this basic configuration, an ignition apparatus 1 is provided for one or more combustors 2 disposed in a gas turbine engine 3. The general illustration in the various figures should not be construed in a limiting sense as to the physical location of the various elements. For example, all of the elements could be installed as part of the engine, although in FIG. 1 some of the elements are shown diagrammatically outside the engine boundary.

#It is also important to note that while the various embodiments of the invention as described herein are particularly directed to or explained in the context of use with gas turbine engines such as are commonly used for aircraft, such descriptions are intended to be exemplary in nature and should not be construed in a limiting sense. The invention is related to combustion initiation, stabilization and restart processes, rather than being limited to specific engine or combustor designs or applications. Those skilled in the art will readily appreciate that the invention can be used with different types of combustors for many types of engines and applications other than in the aerospace and airborne gas turbine applications. For example, the present invention can be applied to combustors for reciprocating and rotary engines, rocket engines particularly liquid fuel rockets, ram jet and pulse jet, to name just a few examples. A few gas turbine engine applications of interest are: jet engines including preburners, afterburners for engines, turbojets, turboprops, turbofans, large gas turbine, medium gas turbines, small gas turbines, marine gas turbines, stationary and mobile industrial gas turbines. Other combustor systems of interest are: residential and industrial furnace applications, can combustors, can annular combustors, annular combustors and dual annular combustors to name a few. As noted, the invention is also applicable to reciprocating and rotary engine applications, such as, for example, automotive applications, an embodiment of which is illustrated and described with reference to FIGS. 7A and 7B. Thus, various embodiments are provided herein for applying the concepts and teachings of the invention to combustors that have a fixed geometry during a combustion cycle, such as a turbine can or annular combustor, and combustors that have a variable geometry during the combustion cycle. For example, a reciprocating engine cylinder in an automobile has a volume that changes with the piston stroke.

#These examples of combustors and engines are not intended to be an exhaustive list, of course, nor are they to limit the scope and application of the invention.