The present disclosure relates to injectors and nozzles, and more particularly to fuel injection such as in gas turbine engines.
Typical fuel injectors that contain flow scheduling valves are passive, where the flow response is fully based on the input pressure. A resistive spring provides the force balance to limit the rate at which the schedule valve opens. These valves can be used to divide flow as well, providing multiple flow paths that can be sequenced/schedule based on inlet fuel pressure, valve open area, and any downstream flow devices such as atomizers.
At relatively low flow conditions, the flow schedule valve is largely responsible for most of the metering and therefore consumes and/or requires the majority of the fuel pressure. At relatively high flow conditions, there is a transition of pressure drop from the valve to other components downstream of the valve.
There are occasions in higher performance combustors where a cooling flow circuit may be required for portions of the flight cycle where certain fuel circuits may be significantly reduced or shut off in flow. The cooling circuit acts to cool by thermal conduction of those circuits.
The conventional techniques have been considered satisfactory for their intended purpose. However, there is an ever present need for improved systems and methods for adjusting cooling flow in passive injection valves. This disclosure provides a solution for this need.
A system includes an injector including a scheduling valve assembly and a nozzle in fluid communication with the scheduling valve assembly. The scheduling valve assembly is configured for regulation of flow from an inlet of the injector to the nozzle. The injector includes two fluid circuits between the inlet of the injector and two respective outlets for staged flow output. A first one of the two fluid circuits is a primary circuit, and a second one of the two fluid circuits is a secondary circuit. A cooling circuit is in fluid communication with the inlet of the injector. The cooling circuit is in thermal communication with the secondary circuit for selectively cooling the secondary circuit at low flow and no flow conditions of the secondary circuit. A separate valve is connected in fluid communication in the cooling circuit for controlling flow through the cooling circuit. The separate valve is configured for active control regardless of pressure at the inlet of the injector. The scheduling valve assembly is configured for passive control of the primary and secondary circuits based on pressure at the inlet of the injector.
A valve spool of the scheduling valve assembly can be biased to a closed position by one or more biasing members of the scheduling valve assembly. The valve spool can be configured to regulate flow from the inlet of the injector to each of the primary and secondary circuits. The valve spool can include a scheduling surface configured to vary flow area through the secondary circuit based on position of the valve spool within the scheduling valve assembly.
The separate valve can be a solenoid valve that has an inlet, an outlet, and a solenoid valve member configured to control flow through the solenoid valve from the inlet to the outlet based on electrical power applied to an armature of the solenoid valve. The inlet of the solenoid valve can be connected in fluid communication with the inlet of the injector. The outlet of the solenoid valve can be connected in fluid communication with the cooling circuit. The outlet of the solenoid valve can connect to the cooling circuit. The cooling circuit can be in thermal communication with the secondary circuit. The cooling circuit can be connected in fluid communication to empty into the primary circuit at a position in the primary circuit that is downstream of the scheduling valve assembly.
The solenoid valve cab be a binary valve configured for binary operation either allowing or disallowing flow through the cooling circuit without an intermediate flow condition between allowing or disallowing flow. The solenoid valve can be a modulating valve configured to vary flow between fully allowing and fully disallowing flow through the cooling circuit with intermediate flow conditions between allowing and disallowing flow.
A check valve can be in fluid communication upstream of where the primary, secondary, and cooling circuits connect to the inlet of the injector. A pressure matching orifice can be included in the primary circuit downstream of the inlet of the injector and upstream of a point where the cooling circuit empties into the primary circuit. Loss of electrical power to the separate valve need not prevent the valve spool positioning itself at a position determined by mechanical components and regulating fuel flow as per a scheduling surface.
The injector can be a first injector in a plurality of injectors each connected in fluid communication with a single manifold for supplying fuel to each injector in the plurality of injectors including the primary, secondary, and cooling circuits of the first injector. The cooling circuit can empty into another injector in the plurality of injectors different from the first injector for issuance into a combustor. The secondary circuit can outlet to a spray outlet of the first injector. The secondary circuit can outlet to a spray outlet of another injector in the plurality of injectors different from the first injector. Each injector in the plurality of injectors can be as described above including a respective separate valve as described above connected thereto. A controller can be electrically connected to the separate valves for individual and/or ganged control thereof.
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 embodiment of a system in accordance with the disclosure is shown in
The system 100 includes an injector 102 having a scheduling valve assembly 104 and a nozzle 106 (labeled in
A cooling circuit 113 is in fluid communication with the inlet 108 of the injector. The cooling circuit 113 is in thermal communication with the secondary circuit 112 for selectively cooling the secondary circuit 112 at low flow and no flow conditions of the secondary circuit 112. A separate valve 114 is connected in fluid communication in the cooling circuit 113 for controlling flow through the cooling circuit 113. The separate valve 114 is configured for active control regardless of pressure at the inlet 108 of the injector 102. The scheduling valve assembly 104 is configured for passive control of the primary and secondary circuits 110, 112 based on pressure at the inlet 108 of the injector 102.
With continued reference to
With reference now to
The solenoid valve 114 is a binary valve configured for binary operation either allowing or disallowing flow through the cooling circuit 113 without an intermediate flow condition between allowing or disallowing flow. It is also contemplated that the solenoid valve 114 can be a modulating valve configured to vary flow between fully allowing and fully disallowing flow through the cooling circuit 113 with intermediate flow conditions between allowing and disallowing flow. For example, the solenoid valve 114 can operate exclusively between restricted flow and fully open flow for the cooling circuit 113. Any other suitable type of valve can be used such as a motorized valve, e.g. separate from the scheduling valve.
With reference now to
With reference now to
With reference now to
A controller 154 is electrically connected to the solenoid valves 114 for individual control thereof (in
Those skilled in the art will readily appreciate that this circumferential arrangement can be modified as needed for a given engine application, that control of the injectors 102 as described herein allows for finely tuned control of fuel circuit cooling and that the solenoid controlled and passive injectors described here are an example and this disclosure applies to any other suitable combination of passive/active injectors. The control can be based on sensor feedback from one or more sensors 156 in the system 100.
Systems and methods as disclosed herein provide potential benefits as explained below. Systems and methods as disclosed herein are fail-safe since failure of the solenoid results in the injector simply reverting to state of art function. Systems and methods as disclosed herein can provide independent control of auxiliary circuits (e.g. to nozzle 106c as shown in
The methods and systems of the present disclosure, as described above and shown in the drawings, provide for adjustment of otherwise passive valves, e.g. to provide actively controlled cooling in fuel injectors for gas turbine engines, e.g. wherein the fuel injection is passively controlled based on input pressure. 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.