Patent Description:
Aircraft turbine engines, such as a turbofan gas turbine engine, may be exposed to numerous and varied environmental conditions both on the ground and in flight. For example, the engine may be exposed to supercooled liquid droplets, ice crystals, sand, dust, or volcanic ash. Such exposure may result in accumulation of ice or other particulate at various locations on or within the engine. Not surprisingly, such accumulation can adversely affect engine performance and/or have various other deleterious effects on engine components.

Presently, most aircraft engines are not equipped with systems that can differentiate between different types of particulate, let alone the quantity and size of the particulate. Knowing the type, quantity, and size of the particulate at various locations within the engine could be useful in determining if, and how much, particulate is accumulating at various locations on or within the engine.

Hence, there is a need for a system and method for sensing particulate ingestion and accumulation at one or more locations within a gas turbine engine. The present invention addresses at least this need. Patent Application Publication No. <CIT> describes sensors monitoring environmental conditions and deformation of aircraft surfaces, and generating an alert when necessary. Patent Application Publication No. <CIT> describes analyzing the sounds of impacts of particles on a surface of a gas turbine engine, comparing them to a store of sounds, and adjusting operation of the engine if necessary. Patent Application Publication No. <CIT> describes debris monitoring in a gas turbine engine by continuous sensing of particulates. The time-domain sensor signal is Fourier transformed to a frequency domain signal. Patent Application Publication <CIT> describes an anti-icing system for a gas turbine engine.

According to a first aspect, there is provided a gas turbine engine ice particulate ingestion detection system includes a first particulate sensor, a second particulate sensor, and a processor. The first particulate sensor is mounted at a first position on the gas turbine engine, where the first position is located upstream of a gas turbine engine component. The first particulate sensor is configured to sense particulate at the first position and supply a first sensor signal representative thereof. The second particulate sensor is mounted at a second position on the gas turbine engine, where the second position is located downstream of the gas turbine engine component and the first position. The second particulate sensor is configured to sense ice particles at the second position and supply a second sensor signal representative thereof. The processor is coupled to receive the first sensor signal and the second sensor signal. The processor is configured, upon receipt of the first and second sensors signal, to: (i) determine the quantity and size of the ice particles at the first position, (ii) determine the quantity and size of the ice particles at the second position, and (iii) determine, based at least on the quantity and size of the ice particles at the first and second positions, an amount of ice accumulated on the gas turbine engine component; to compare the amount of ice accumulated on the gas turbine engine component to a threshold value; and to generate a signal when the amount exceeds the threshold value, where the gas turbine engine component is a fan and where the first and second sensors are each optical sensors.

According to a second aspect, there is provided a method for determining particulate accumulation in a gas turbine engine, where the particulate is frozen ice particles. The method includes the steps of sensing ice particles at a first position on the gas turbine engine and supplying a first sensor signal representative thereof, where the first position is located upstream of a gas turbine engine component, and sensing ice particles at a second position on the gas turbine engine and supplying a second sensor signal representative thereof, where the second position is located downstream of the gas turbine engine component and the first position. The first sensor signal is processed to determine the quantity, and size of the ice particles at the first position, and the second sensor signal is processed to determine the quantity, and size of the ice particles at the second position. Based at least on the quantity and size of the ice particles at the first and the second positions, an amount of ice particles accumulated on the gas turbine engine component is determined. The amount of ice accumulated on the gas turbine engine component is compared to a threshold value. A signal is generated when the amount exceeds the threshold value. The first and second sensors are each optical sensors, and the gas turbine engine component is a fan.

Furthermore, other desirable features and characteristics of the particulate ingestion and accumulation system and method will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.

Referring to <FIG>, a simplified functional diagram of an exemplary engine system <NUM> for an aircraft is depicted and includes a turbofan gas turbine engine <NUM> and an engine control <NUM>. In the depicted embodiment, the turbofan gas turbine engine <NUM> is implemented as multi-spool gas turbine engine and, as <FIG> further depicts, each includes an intake section <NUM>, a compressor section <NUM>, a combustion section <NUM>, a propulsion turbine <NUM>, and an exhaust section <NUM>. The intake section <NUM> includes a fan <NUM>, which draws air into the intake section <NUM>. A fraction of the air exhausted from the fan <NUM> is directed through a bypass section <NUM> disposed between a fan case <NUM> and an engine cowl <NUM>, and provides a forward thrust. The remaining fraction of air exhausted from the fan <NUM> is directed into the compressor section <NUM>.

The compressor section <NUM>, which may include one or more compressors, raises the pressure of the air directed into it from the fan <NUM>, and directs the compressed air into the combustion section <NUM>. In the depicted embodiment, only a single compressor <NUM> is shown, though it will be appreciated that one or more additional compressors could be used. In the combustion section <NUM>, which includes a combustor assembly <NUM>, the compressed air is mixed with fuel supplied from a non-illustrated fuel source. The fuel and air mixture is combusted, and the high energy combusted air mixture is then directed into the propulsion turbine <NUM>.

The propulsion turbine <NUM> includes one or more turbines. In the depicted embodiment, the propulsion turbine <NUM> includes two turbines, a high pressure turbine <NUM>, and a low pressure turbine <NUM>. However, it will be appreciated that the propulsion turbine <NUM> could be implemented with more or less than this number of turbines. No matter the particular number, the combusted air mixture from the combustion section <NUM> expands through each turbine <NUM>, <NUM>, causing it to rotate. The combusted air mixture is then exhausted through the exhaust section <NUM> providing additional forward thrust.

As the turbines <NUM> and <NUM> rotate, each drives equipment in the engine <NUM> via concentrically disposed shafts or spools. Specifically, the high pressure turbine <NUM> drives the compressor <NUM>, via a high pressure spool <NUM>, at a rotational speed that is generally referred to as core engine speed (N2). The low pressure turbine <NUM> drives the fan <NUM>, via a low pressure spool <NUM>, at a rotational speed that is generally referred to as fan speed (N1). Though not included in the depicted embodiment, it will be appreciated that in some embodiments the engine <NUM> may include a reduction gearbox between the low pressure turbine <NUM> and the fan <NUM>.

The engine control <NUM> is in operable communication with, and is configured to control the operation of the engine <NUM>. In the depicted embodiment, the engine control <NUM> is configured, in response to a throttle setting <NUM>, to control the flow of fuel to, and thus the power generated by, the engine <NUM>. The engine control <NUM> is also configured to control the positions of one or more variable geometry devices, such as, for example, variable inlet guide vanes <NUM>.

As <FIG> further depicts, the depicted engine system <NUM> also includes a plurality of particulate sensors <NUM> and a processor <NUM>. The sensors <NUM> are each disposed at different positions on (or within) the gas turbine engine <NUM>, and each sensor <NUM> is configured to sense particulate at its disposed position. In the depicted embodiment, the engine system <NUM> includes five particulate sensors disposed at five different locations. It will be appreciated that this is merely exemplary of one embodiment, and that the engine system <NUM> could be implemented with more or less than this number of particulate sensors <NUM>. According to the invention, the particulate sensors <NUM> are implemented using optical sensors. Other examples of particulate sensors <NUM> include capacitive sensors, electrostatic sensors, lidar sensors, and backscatter sensors, just to name a few. It will additionally be appreciated that the type of particulate that each sensor <NUM> is configured to sense may vary. According to the invention, the sensors <NUM> are configured to sense ice particles. Other examples of types of particulate include dust and volcanic ash, just to name a few.

Regardless of the total number and specific type of sensors <NUM> that are used, the engine system <NUM> includes at least a first particulate sensor <NUM>-<NUM> and a second particulate sensor <NUM>-<NUM>. The first particulate sensor <NUM>-<NUM> is mounted at a first position on the gas turbine engine <NUM>, and the second particulate sensor <NUM>-<NUM> is mounted at a second position on the gas turbine engine <NUM>. It is seen that the first position is located at a first side of a gas turbine engine component, and the second position is located at a second side of the gas turbine engine component and downstream of the first position. Thus, the first particulate sensor <NUM>-<NUM> senses particulate at the first position and supplies a first sensor signal representative thereof, and the second particulate sensor <NUM>-<NUM> senses particulate at the second position and supplies a second sensor signal representative thereof. Although the particular gas turbine engine component may vary, in the depicted embodiment it is the fan <NUM>.

The processor <NUM> is coupled to receive the first sensor signal and the second sensor signal. The processor <NUM> is configured, upon receipt of the first and second sensor signals, to determine the type, quantity, and size of the particulate at the first and second positions. The processor <NUM> is additionally configured to determine, based at least on the quantity and size of the particulate at the first and second positions, the amount of particulate that has accumulated on the gas turbine engine component (e.g., the fan <NUM>). It will be appreciated that the type of particulate accumulated on the gas turbine engine component may, at least in some embodiments, different from the type of particulate sensed at the first and second positions. Thus, for example, when the sensors <NUM> are configured to sense super-cooled water droplets and/or ice crystals, the processor <NUM> may determine the amount of ice that has accreted on the gas turbine engine component. As an example not according to the present invention, if the sensors <NUM> were to be configured to sense dust or volcanic ash, the processor <NUM> may determine the amount of dust or ash (which may be solidified into glass) that has accumulated on the gas turbine engine component.

In addition to determining the amount of the particulate that has accumulated on the gas turbine engine component, the processor is further configured to compare the amount of accumulated particulate to a threshold value. This threshold value may vary and may depend, for example, on the type of particulate being sensed, on the type of engine, and on the particular engine component. In any case, when the processor <NUM>, based on this comparison, determines that the accumulated amount exceeds the threshold value, the processor <NUM> generates a signal. This signal may be used to generate an alert, to initiate a mitigation or corrective action, or both.

When the signal is used to generate an alert, then the system <NUM> additionally includes an alert generator <NUM>. The alert generator <NUM> may be implemented as a visual alert, an aural alert, a haptic alert, or any one of numerous combination of these types of alerts. No matter how it is implemented, the alert generator <NUM> is coupled to receive the signal from the processor <NUM> and is configured, upon receipt of the signal, to generate an alert. The alert may communicate, for example, the type of particulate accumulated, which may in turn be used to determine a type of mitigation or corrective action to pursue.

When the signal is used to initiate a mitigation or corrective action, the signal may be supplied to one or more of the engine control <NUM>, one or more anti-ice heaters <NUM>, one or more controllable bypass channels (or valves) <NUM>, and one or more display devices <NUM>. The specific mitigation or corrective action, as may be appreciated, may be a function of the particular type of accumulated particulate, and preferably results in preventing or mitigating further particulate accumulation. As noted above, the engine control <NUM> is configured to, among other things, control at least the rotational speed of one or more of the gas turbine engine components. In some embodiments, the engine control <NUM> is further configured, upon receipt of the signal from the processor <NUM>, to increase the rotational speed of one or more of the gas turbine components. This increase in speed will force a shed of the accumulated particulate and/or increase the temperature of the gas turbine engine component. In some embodiments, the engine control <NUM> may also be configured, upon receipt of the signal, to vary the positons of the one or more variable geometry devices (e.g., the variable inlet guide vanes <NUM>). When the signal is supplied to the anti-ice heaters <NUM>, the heaters <NUM>, upon receipt of the signal, will generate heat.

The signal from the processor <NUM> may also be used to open one or more of the controllable bypass channels <NUM>. The signal may be supplied directly to the controllable bypass channels <NUM> or to the engine control <NUM>, which in turn opens the channels. Regardless, opening the bypass channels <NUM> will provide a flow path from the compressor <NUM> to the bypass section <NUM>, which will exhaust particulate along the compressor outer diameter flow path out to the bypass section <NUM>, thereby bypassing the combustor <NUM> and turbines <NUM>, <NUM>. When the signal is supplied to the one or more display devices <NUM>, the display device <NUM> render, for example, a message to change the route or altitude of the vehicle (e.g., aircraft), to thereby exit the particulate source. It will be appreciated that the message may also, or instead, be supplied by the alert generator.

As was previously noted, the engine system <NUM> may include additional sensors. Indeed, in the depicted embodiment, the engine system <NUM> includes three additional particulate sensors <NUM> disposed at three different additional locations. More specifically, in addition to the first and second particulate sensors <NUM>-<NUM>, <NUM>-<NUM>, the depicted system <NUM> includes a third particulate sensor <NUM>-<NUM>, a fourth particulate sensor <NUM>-<NUM>, and a fifth particulate sensor <NUM>-<NUM>.

The third particulate sensor <NUM>-<NUM> is mounted at a third position on the gas turbine engine <NUM>, the fourth particulate sensor <NUM>-<NUM> is mounted at a fourth position on the gas turbine engine <NUM>, and the fifth particulate sensor <NUM>-<NUM> is mounted at a fifth position on the gas turbine engine <NUM>. Here, the third position is located at a first side of a second gas turbine engine component and downstream of the second position, and the fourth position is located at a second side of the second gas turbine engine component and downstream of the third position. In this embodiment, the second side of the second gas turbine engine component corresponds to the first side of a third gas turbine engine component, and the fifth position is located at the second side of the third gas turbine engine component and downstream of the fourth position. Although the second and third gas turbine engine components may vary, in the depicted embodiment each is a different stage (e.g., the first and second stages) of the compressor <NUM>.

The third particulate sensor <NUM>-<NUM> senses particulate at the third position and supplies a third sensor signal representative thereof to the processor <NUM>, the fourth particulate sensor <NUM>-<NUM> senses particulate at the fourth position and supplies a fourth sensor signal representative thereof to the processor <NUM>, and the fifth particulate sensor senses particulate at the fifth position and supplies a fifth sensor signal representative thereof to the processor <NUM>.

The processor <NUM>, upon receipt of the additional sensor signals, determines the type, quantity, and size of particulate at the different positions. The processor <NUM> additionally determines, based at least on the quantity and size of particulate at each of the different positions, the amount of particulate accumulated on one or more additional gas turbine engine components (e.g., the first and second compressor stages).

One embodiment of a process for determining particulate accumulation in the gas turbine engine <NUM> that the system <NUM> implements is depicted, in flowchart form, in <FIG>, and will now be described. Before proceeding, it is noted that the depicted process <NUM> is when the system <NUM> includes only two particulate sensors <NUM> (e.g., the first and second particulate sensors), but could readily be expanded for a system that includes three or more sensors <NUM>.

The process begins by sensing particulate at a first position on the gas turbine engine and supplying a first sensor signal representative thereof (<NUM>), and sensing particulate at a second position on the gas turbine engine and supplying a second sensor signal representative thereof (<NUM>). As noted above, the first position is located at a first side of a gas turbine engine component, and the second position is located at a second side of the gas turbine engine component and downstream of the first position. The first sensor signal is processed to determine the type, quantity, and size of the particulate at the first position (<NUM>), and the second sensor signal is processed to determine type, quantity, and size of the particulate at the second position (<NUM>).

After the type, quantity, and size of the particulate at the first and second locations are determined, the amount of particulate accumulated on the gas turbine engine component is then determined (<NUM>). As previously noted, this determination is based at least on the quantity and size of particulate at the first and the second positions. The amount of particulate accumulated on the gas turbine engine component is then compared to a threshold value (<NUM>). If the amount exceeds the threshold value, then an alert is generated (<NUM>). If not, then the process <NUM> repeats. Though not depicted in <FIG>, it will be appreciated that the process <NUM> may be further expanded to include, for example, communicating the type of particulate accumulated on the gas turbine engine component, and/or initiating one or more mitigation or corrective actions.

The systems and methods described herein differentiate between different types, quantities, and sizes of particulate at various locations within a gas turbine engine, which allows determining if, and how much, particulate is accumulating at various locations on or within the engine.

In one embodiment, a gas turbine engine particulate ingestion detection system includes a first particulate sensor, a second particulate sensor, and a processor. The first particulate sensor is mounted at a first position on the gas turbine engine, where the first position is located upstream of a gas turbine engine component. The first particulate sensor is configured to sense particulate at the first position and supply a first sensor signal representative thereof. The second particulate sensor is mounted at a second position on the gas turbine engine, where the second position is located downstream of the gas turbine engine component and downstream of the first position. The second particulate sensor is configured to sense particulate at the second position and supply a second sensor signal representative thereof. The processor is coupled to receive the first sensor signal and the second sensor signal. The processor is configured, upon receipt of the first and second sensors signal, to: (i) determine the type, quantity, and size of the particulate at the first position, (ii) determine the type, quantity, and size of the particulate at the second position, and (iii) determine, based at least on the quantity and size of the particulate at the first and second positions, an amount of particulate accumulated on the gas turbine engine component.

These aspects and other embodiments may include one or more of the following features. The processor may be further configured to compare the amount of the particulate accumulated on the gas turbine engine component to a threshold value, and generate a signal when the amount exceeds the threshold value. The threshold value may depend on one or more of: the one or more types of particulate being sensed, the type of engine, and the particular engine component. An alert generator may coupled to receive the signal from the processor and configured, upon receipt of the signal, to generate an alert. The alert may communicate the type of particulate accumulated on the gas turbine engine component. The signal may initiate one or more actions to prevent or mitigate further particulate accumulation. The one or more actions may include one or more of: increasing the rotational speed of one or more gas turbine engine components; varying positons of one or more variable geometry devices; energizing one or more heaters; opening one or more compressor bypass channels; and displaying one or more messages to exit a source of the particulate. The particulate may comprise one or more of super-cooled water droplets, ice crystals, dust, and volcanic ash. The first and second sensors may each be selected from the group consisting of an optical sensor, a capacitive sensor, an electrostatic sensor, a lidar sensor, and a backscatter sensor. The system may further include a plurality of additional particulate sensors, where each additional particulate sensor is mounted at different positions on the gas turbine engine that are each different from the first and second positions, and each additional particulate sensor is configured to sense particulate at its position and supply an additional sensor signal representative thereof, and the processor may be further coupled to receive each of the additional sensor signals, and further configured, upon receipt of the additional sensors signal, to: determine type, quantity, and size of particulate at the different positions, and determine, based at least on the quantity and size of particulate at each of the different positions, an amount of the particulate accumulated on one or more additional gas turbine engine components. T\he first turbine engine component may be a fan, and the additional turbine engine components may include a first compressor stage and a second compressor stage.

In another embodiment, a method for determining particulate accumulation in a gas turbine engine includes sensing particulate at a first position on the gas turbine engine and supplying a first sensor signal representative thereof, where the first position is located upstream of a gas turbine engine component, and sensing particulate at a second position on the gas turbine engine and supplying a second sensor signal representative thereof, where the second position is located downstream of the gas turbine engine component and downstream of the first position. The first sensor signal is processed to determine the type, quantity, and size of the particulate at the first position, and the second sensor signal is processed to determine the type, quantity, and size of the particulate at the second position. Based at least on the quantity and size of the particulate at the first and the second positions, an amount of the particulate accumulated on the gas turbine engine component is determined.

These aspects and other embodiments may include one or more of the following features. Comparing the amount of the particulate accumulated on the gas turbine engine component to a threshold value, and generating an alert when the amount exceeds the threshold value. The threshold value may depend on one or more of: the one or more types of particulate being sensed, the type of engine, and the particular engine component. The alert may communicate the type of particulate accumulated on the gas turbine engine component. One or more actions to prevent or mitigate further particulate accumulation may be initiated. The one or more actions may include one or more of: increasing the rotational speed of one or more gas turbine engine components; varying positons of one or more variable geometry devices; energizing one or more heaters; opening one or more compressor bypass channels; and displaying one or more messages to exit a source of the particulate. The particulate may comprise one or more of super-cooled water droplets, ice crystals, dust, and volcanic ash. Sensing particulate at a plurality of positions in the gas turbine engine that are each different from the first and second positions, and supplying a plurality of additional sensor signals. Processing each of the additional sensor signals to determine type, quantity, and size of particulate at the different positions, and determining, based at least on the quantity and size of particulate at each of the different positions, an amount of the particulate accumulated on one or more additional gas turbine engine components.

In yet another embodiment, a gas turbine engine particulate ingestion detection system, wherein the particulate is one or both of super cooled liquid droplets and frozen ice particles, includes a first particulate sensor, a second particulate sensor, and a processor. The first particulate sensor is mounted at a first position on the gas turbine engine, where the first position located at a first side upstream of a gas turbine engine component. The first particulate sensor is configured to sense particulate at the first position and supply a first sensor signal representative thereof. The second particulate sensor is mounted at a second position on the gas turbine engine, where the second position located downstream of the gas turbine engine component and downstream of the first position. The second particulate sensor is configured to sense particulate at the second position and supply a second sensor signal representative thereof. The processor is coupled to receive the first sensor signal and the second sensor signal, and is configured, upon receipt of the first and second sensors signal, to: (i) determine the type, quantity, and size of the particulate at the first position, (ii) determine the type, quantity, and size of the particulate at the second position, (iii) determine, based at least on the quantity and size of the particulate at the first and second positions, an amount of ice accreted on the gas turbine engine component, (iv) compare the amount of ice accreted on the gas turbine engine component to a threshold value, and (v) generate a signal when the amount exceeds the threshold value.

Techniques and technologies may be described herein in terms of functional and/or logical block components, and with reference to symbolic representations of operations, processing tasks, and functions that may be performed by various computing components or devices. Such operations, tasks, and functions are sometimes referred to as being computer-executed, computerized, software-implemented, or computer-implemented. In practice, one or more processor devices can carry out the described operations, tasks, and functions by manipulating electrical signals representing data bits at memory locations in the system memory, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to the data bits. It should be appreciated that the various block components shown in the figures may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions.

When implemented in software or firmware, various elements of the systems described herein are essentially the code segments or instructions that perform the various tasks. The program or code segments can be stored in a processor-readable medium or transmitted by a computer data signal embodied in a carrier wave over a transmission medium or communication path. The "computer-readable medium", "processor-readable medium", or "machine-readable medium" may include any medium that can store or transfer information. Examples of the processor-readable medium include an electronic circuit, a semiconductor memory device, a ROM, a flash memory, an erasable ROM (EROM), a floppy diskette, a CD-ROM, an optical disk, a hard disk, a fiber optic medium, a radio frequency (RF) link, or the like. The computer data signal may include any signal that can propagate over a transmission medium such as electronic network channels, optical fibers, air, electromagnetic paths, or RF links. The code segments may be downloaded via computer networks such as the Internet, an intranet, a LAN, or the like.

Claim 1:
A gas turbine engine particulate ingestion detection system (<NUM>), wherein the particulate is frozen ice particles, comprising:
a first particulate sensor (<NUM>-<NUM>) mounted at a first position on the gas turbine engine (<NUM>), the first position located upstream of a gas turbine engine component (<NUM>), the first particulate sensor configured to sense ice particles at the first position and supply a first sensor signal representative thereof;
a second particulate sensor (<NUM>-<NUM>) mounted at a second position on the gas turbine engine, the second position located downstream of the gas turbine engine component (<NUM>) and the first position, the second particulate sensor configured to sense ice particles at the second position and supply a second sensor signal representative thereof; and
a processor (<NUM>) coupled to receive the first sensor signal and the second sensor signal, the processor configured, upon receipt of the first and second sensors signal, to:
determine quantity and size of the ice particles at the first position;
determine quantity and size of the ice particles at the second position;
determine, based at least on the quantity and size of the ice particles at the first and second positions, an amount of ice accumulated on the gas turbine engine component;
compare (<NUM>) the amount of ice accumulated on the gas turbine engine component to a threshold value; and
generate (<NUM>) a signal when the amount exceeds the threshold value;
wherein the gas turbine engine component is a fan (<NUM>); and
wherein the first and second sensors are each optical sensors.