Patent Application
20200191383
The present disclosure relates to multipoint injection, and more particularly to multipoint fuel injection, e.g., for gas turbine engines.
Industrial gas turbine engines can employ radial inflow fuel/air mixers and usually use axially mounted fuel injectors. The actual fuel injection is limited to a relatively low number of injection sights, e.g., less than twenty injection sites.
The conventional techniques have been considered satisfactory for their intended purpose. However, there is an ever present need for improved fuel injection, e.g., for industrial gas turbine engines. This disclosure provides a solution for this need.
An injection system includes a radial swirler defining an axis and including a plurality of radial swirl vanes configured to direct a radially inward flow of compressor discharge air entering swirler inlets between the radial swirl vanes in a swirling direction with a circumferential component around the axis. The radial swirler includes an outlet oriented in an axial direction to direct swirling compressor discharge air mixed with fuel in an axial direction. An injector ring is included radially outward from the swirler inlets. The fuel injector ring is aligned with the axis and includes a plurality of injection orifices directed towards the swirler inlets for injecting fuel into the radial swirler.
The injector ring can be a first injector ring and a second injector ring can be included axially adjacent to the first injector ring, the second injector ring being aligned with the axis and including a plurality of injection orifices directed towards the swirler inlets for injecting fuel into the radial swirler, wherein the first and second injector rings are connected to two separate, fluidly isolated fuel circuits for staged fuel injection. A third injector ring can be included axially adjacent to the first and second injector rings, the third injector ring being aligned with the axis and including a plurality of injection orifices directed towards the swirler inlets for injecting fuel into the radial swirler, wherein the first, second, and third injector rings are connected to three separate, fluidly isolated fuel circuits for staged fuel injection.
There can be at least 200 injection orifices total among the first, second, and third injector rings. Each swirl vane can define a curved swirl profile extending from a leading edge of the vane to a trailing edge of the vane, wherein the curved swirl profile at the leading edge is normal to a circumference defined by the leading edges of the swirl vanes. There can be at least one of the injection orifices aligned with each of the swirler inlets, wherein the injection orifices are positioned to inject fuel between circumferentially adjacent swirl vanes without impinging fuel on the swirl vanes. There can be at least two injection orifices aligned with each swirler inlet.
A combustor case can enclose the radial swirler and the injector ring. A converging diverging outer wall can be included in the outlet of the radial swirler. A conical inner wall can be mounted inboard of the swirl vanes. A combustor liner can be included in board of the combustor case defining a combustion volume therein. The combustor liner can have an inlet connected to the radial swirler with the outlet of the radial swirler in fluid communication with the combustion volume. A fuel conduit can pass through a bulkhead of the combustor case and can connect to the injector ring for fluid connection of the injector ring to a source of fuel. Second and third injector rings as described above can be included and an exhaust emission gas sampling sensor can be mounted in an outlet of the combustor liner. A controller can be operatively connected to receive exhaust emission gas feedback from the exhaust emission gas sampling sensor. A plurality of electronic flow divider valves can be included, with one of the valves connected in each respective one of the fuel circuits. The electronic flow divider valves can be operatively connected to the controller for individual control of flow rates to each of the injector rings based on exhaust emission gas feedback.
A method of fuel injection includes issuing fuel through a plurality of axially adjacent injector rings into a radial swirler. The method includes varying flow rate through each of the injector rings individually to control exhaust gas emissions over varying engine operating conditions. The method can include using exhaust emission gas sampling feedback to control the flow rate through each of the injector rings.
A method of injecting includes directing fuel flow from an injector ring to a direction including a circumferential component.
These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of an injection system in accordance with the disclosure is shown in
The injection system 100 includes a radial swirler 102 defining an axis A and including a plurality of radial swirl vanes 104 configured to direct a radially inward flow of compressor discharge air, schematically represented by flow arrows 106, entering swirler inlets 108 (only a few of which are labeled in
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A method of fuel injection includes issuing fuel through a plurality of axially adjacent injector rings, e.g., injector rings 114, 116, 118, into a radial swirler, e.g., swirler 102. The method includes varying flow rate through each of the injector rings individually to control exhaust gas emissions, e.g., by controlling the temperature profiles at the outlet 156, over varying engine operating conditions. The method can include using exhaust emission gas sampling feedback to control the flow rate through each of the injector rings. Controlling fuel flow through each injector ring controls mixing in air zones, air layers with greater flow can receive proportionally greater fuel flow. One or more injector ring can be shut off completely for fuel staging, e.g., for low power operation or for ignition. This controllability of the individual injector rings also allows adaptation, e.g., for changing hardware quality, fuel type, operating point, and the like.
The methods and systems of the present disclosure, as described above and shown in the drawings, provide for fuel injection, e.g., in industrial gas turbine engines, with superior properties including improved control of exhaust gas emissions over a range of engine operating conditions. While the apparatus and methods of the subject disclosure have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the scope of the subject disclosure.
