Method, computer-implemented method and computer program for identifying surge events in turbine engine

Abstract

The invention relates to a method, a computer-implemented method and a computer program for identifying surge events in a turbine engine. More specifically, the invention relates to a method for detecting a surge event based on the temperature of the exhaust gas and its variation over time and based on the rotational speed of the engine before the operation of the turbine engine is hindered, in order to trigger an alarm signal if certain conditions are met, surge of the engine can be expected, detected, and in some cases avoided.

Description

Technical Field

[0001] This invention relates to a method suitable for detecting surge in a turbine engine, a computer-implemented method, and a computer program for implementing this method. In particular, the method relates to detecting surge events in a turbine engine core compressor that supplies compressed air to the turbine engine. Background Technology

[0002] Surge events in turbine engines correspond to disturbances in the gas flow from the intake to the exhaust, a condition that typically occurs within the engine. More specifically, during surge, there may be no gas flow in the compressor or even reverse gas flow. Such events can damage the engine, reducing its availability and increasing maintenance duration and costs. Furthermore, the engine controller may abruptly shut down the engine, impacting its availability to the aircraft.

[0003] This can occur when the engine ingests sand or dust and becomes clogged. The burner may become blocked, and then combustion in the combustion chamber deteriorates. This can lead to surge events in the engine's core compressor.

[0004] Early detection of surge events is beneficial because it allows for engine shutdown and / or planning of minor maintenance operations to restore full functionality before engine deterioration occurs. Consequently, the overall availability of the aircraft can be improved, as it is minimally affected by surge events in the engine. Furthermore, early detection or anticipation of surge events increases aircraft safety because the engine will undergo maintenance operations rather than facing an unexpected automatic shutdown at a later stage.

[0005] This method can be specifically applied to auxiliary power units (APUs) in aircraft.

[0006] Several methods for detecting surge in a loaded compressor already exist and are implemented by the APU's controller. However, these methods typically detect surge in the later stages, when its impact on the engine is stronger and causes the controller to shut down the engine. Summary of the Invention

[0007] The present invention aims to propose a novel method that allows for the detection of surge in the core compressor of an engine.

[0008] The present invention aims to provide a method that allows for the detection of low-severity surge in an engine, thereby enabling the maintenance of engine integrity.

[0009] The present invention aims to provide a method that improves engine availability, and thus improves aircraft availability, and reduces aircraft maintenance costs.

[0010] The present invention also aims to provide a method that improves aircraft safety by notifying the maintenance team in advance of the occurrence or likelihood of a surge event, thereby preventing automatic engine shutdown during continuous flight.

[0011] This invention proposes a method for identifying surge events in a turbine engine, the method comprising:

[0012] a. Obtain the temperature values ​​of the exhaust gases at multiple points in time during engine operation.

[0013] b. Obtain the temperature change index based on the temperature value of the emitted gas.

[0014] c. If, at a given time, both the first and second criteria are met—where the first criterion includes at least one temperature value higher than a predetermined emission temperature threshold and the second criterion includes at least one value of a temperature change index higher than a first predetermined temperature change threshold—then:

[0015] i. Define the monitoring interval, which is:

[0016] • Extended from the moment when both the first and second criteria are met.

[0017] • Extend the duration of continuous compliance with both the first and second criteria for the same length of time.

[0018] ii. During the monitoring interval, obtain a set of values ​​for the rotational speed of the engine shaft, determine the minimum value in the set, and compare the minimum speed value with a first predetermined speed threshold.

[0019] iii. Obtain a set of temperature values ​​for the emitted gas during the monitoring interval, calculate the temperature difference between the highest and lowest temperature values ​​in the set, and compare this temperature difference with a first predetermined temperature difference threshold.

[0020] d. An alarm signal is triggered when the minimum speed value is lower than the first predetermined speed threshold and the temperature difference is higher than the predetermined temperature difference threshold in at least two separate monitoring intervals.

[0021] This method is applicable to detecting surge in the core compressor of a turbine engine. The core compressor is the compressor that directly supplies compressed air to the engine. The core compressor has a different function than the load compressor. The load compressor uses the engine's mechanical energy to generate aerodynamic energy for other systems outside the engine itself; for example, in an aircraft, the load compressor generates compressed air for cabin pressurization.

[0022] Advantageously, the temperature of the engine's exhaust gases can be measured throughout the entire operating phase of the engine.

[0023] The minimum duration of the monitoring interval can be the duration between two consecutive temperature measurements. This would be the case where the first and second criteria are met only at a single moment. The temperature change index can be calculated based on the derivative of the difference between two consecutive temperature values ​​divided by the time elapsed between the two measurements.

[0024] Alarm signals can be signals to computers, such as engine controllers, or to autopilot computers, such as autopilot computers. Alarm signals can also be messages to people, such as written messages or indicator lights to pilots, maintenance teams, or maintenance software.

[0025] Alarm signals can be used by the engine controller to trigger technical effects in engine operation, such as modifying engine operating conditions.

[0026] Obtaining values ​​can represent the steps of measuring and / or storing data representing those values. This is especially true if the invention is implemented during engine operation.

[0027] Obtaining values ​​can also refer to the step of retrieving data representing those values ​​from memory. This is especially true if the invention is implemented after the engine's operational phase. For example, in the case of an aircraft, this might be the case if data is analyzed after the aircraft has already landed following flight.

[0028] Substeps i), ii), and iii) of step c) are triggered only if the first criterion and the second criterion are met simultaneously at the same time. Similarly, the monitoring interval defined in substep i) is extended to continuously satisfy multiple consecutive data points that simultaneously meet the first criterion and the second criterion.

[0029] In some embodiments of the invention, an alarm signal is triggered only if the minimum speed value is below the first predetermined speed threshold and the temperature difference is above the predetermined temperature difference threshold in two consecutive extended intervals. Detection of these two conditions in isolated extended intervals may be a false positive in some cases and may be an indication or precondition of surge in the engine in others; however, detection of these two conditions in two consecutive extended intervals represents surge or a precondition of surge in the engine. Therefore, in some embodiments of the invention, it is possible to selectively ignore the detection of these two conditions occurring in two separate, non-consecutive intervals, especially when the two events occur in intervals that are very far apart in time. In these embodiments, an alarm signal is triggered only when both conditions occur in two consecutive extended intervals.

[0030] In some embodiments of the invention, an alarm signal is triggered if the condition is met in two consecutive monitoring intervals. Therefore, in such an embodiment, if the condition is met in three consecutive individual monitoring intervals, two consecutive alarm signals will be triggered.

[0031] In some embodiments of the present invention, step c is performed only if the temperature change index is also below the second predetermined temperature change threshold.

[0032] Therefore, in addition to the first and second criteria, the execution of sub-steps i), ii), and iii) of step c is also conditional upon a third criterion. This third criterion allows for the filtering out of erroneous values ​​in the temperature change index.

[0033] In this implementation, the analysis of the engine shaft rotation speed and temperature difference during the monitoring interval is therefore performed only during the monitoring interval under the following conditions:

[0034] - At least one temperature value is higher than a predetermined emission temperature threshold, and

[0035] - At least one value of the temperature change index is higher than a first predetermined temperature change threshold and lower than a second predetermined temperature change threshold.

[0036] In some embodiments of the present invention, in step c), the monitoring interval is extended to include a time interval that is exactly before the first moment when the first criterion and the second criterion are met.

[0037] The monitoring interval in which time has been added before the first occurrence of the first and second standards and / or after the last consecutive occurrence of the first and second standards is called the extended interval.

[0038] Therefore, the method of the present invention includes the step of defining an extended time interval, referred to as an extended interval, which includes an initial monitoring interval during which a first criterion and a second criterion are continuously met, the extended interval having a duration longer than the duration of the monitoring interval.

[0039] "Exactly before" refers to a time period that is before and continuous with the monitoring interval, such that the extended interval is a continuous time interval that includes the time before the monitoring interval and the monitoring interval itself.

[0040] In practice, in the method of this invention, only exhaust temperature and temperature changes are actively monitored throughout the entire operation of the engine. However, when outliers of these variables are detected over a short period of time, these and other variables are further investigated at the time before and / or after the first indication of possible surge in order to confirm whether surge has indeed occurred.

[0041] In some embodiments of the invention, in step c), the monitoring interval is extended to include a time interval that occurs exactly after the last consecutive occurrence of the condition that satisfies the first and second criteria within the monitoring interval.

[0042] "Exactly after" refers to a period that is after and continuous with the monitoring interval, such that the extended interval is a non-discontinuous time interval, which includes the time after the monitoring interval and the monitoring interval itself.

[0043] In other embodiments, the extension interval may include a time interval that is exactly before and exactly after the monitoring interval, such that the extension interval represents the amount by which the monitoring interval is extended before and after the initial monitoring interval.

[0044] The monitoring interval can be extended between 2 and 30 seconds, for example, by 10 seconds.

[0045] The extended interval can include, for example, 5 seconds before the monitoring interval and 5 seconds after the monitoring interval.

[0046] In some embodiments of the present invention, in step d), an alarm signal is triggered only if the minimum speed value is also higher than a second predetermined speed threshold.

[0047] Therefore, in order to trigger the alarm signal in step d), the following condition must be met:

[0048] - The minimum speed value is lower than a first predetermined speed threshold and higher than a second predetermined speed threshold, and

[0049] - The temperature difference is higher than the predetermined temperature difference threshold.

[0050] This third condition allows for the filtering out of erroneous values ​​for the minimum engine speed.

[0051] The method according to the invention can be implemented as a computer-based method. In particular, the method can be implemented by a computer, a controller, or any equivalent device.

[0052] Specifically, the present invention extends to a computer-implemented method for identifying surge events in a turbine engine, the method comprising:

[0053] a. Obtain the temperature values ​​of the exhaust gases at multiple points in time during engine operation.

[0054] b. Obtain the temperature change index based on the temperature value of the emitted gas.

[0055] c. If at a given time, both the first and second criteria are met—the first criterion includes at least one temperature value higher than a predetermined emission temperature threshold and the second criterion includes at least one value of a temperature change index higher than a first predetermined temperature change threshold—then:

[0056] i. Define the monitoring interval, which is:

[0057] • Extended from the moment when both the first and second criteria are met.

[0058] • Extend the duration of continuous compliance with both the first and second criteria for the same length of time.

[0059] ii. During the monitoring interval, obtain a set of values ​​for the rotational speed of the engine shaft, determine the minimum value in the set, and compare the minimum speed value with a first predetermined speed threshold.

[0060] iii. Obtain a set of temperature values ​​for the emitted gas during the monitoring interval, calculate the temperature difference between the highest and lowest temperature values ​​in the set, and compare this temperature difference with a first predetermined temperature difference threshold.

[0061] d. An alarm signal is triggered when the minimum speed value is lower than the first predetermined speed threshold and the temperature difference is higher than the predetermined temperature difference threshold in at least two separate monitoring intervals.

[0062] Specifically, obtaining a set of values ​​for the rotational speed of the engine shaft and a set of values ​​for the temperature of the engine exhaust gases may include retrieving values ​​from memory.

[0063] In this invention, values ​​can be retrieved from any memory accessible to a computer.

[0064] Specifically, when the method is implemented during engine operation and the extension interval is extended before the monitoring interval, the values ​​stored in the memory must be retrieved. When the extension interval is extended after the monitoring interval, values ​​can be collected directly from the measurements and used for processing and / or stored in the memory.

[0065] Furthermore, in some implementations, whenever the minimum speed value is lower than the predetermined speed threshold and the temperature difference is higher than the predetermined temperature difference threshold, if the value of the counter is lower than 2, the counter is incremented, and when the value of the counter reaches 2, an alarm signal is triggered and the counter is reset to zero.

[0066] Whenever there is an extended interval where neither of these two conditions is met, the counter can be reset to zero so that an alarm is triggered only if both conditions are met in two consecutive extended intervals.

[0067] Therefore, during the entire monitoring interval, whenever the minimum speed value is higher than the predetermined speed threshold or the temperature difference is lower than the predetermined temperature gap threshold, the counter is reset to zero.

[0068] The invention also extends to a computer program that includes instructions for implementing the method of the invention when the program is run on a computer.

[0069] The invention also extends to other possible combinations of the features described above and in the following description with reference to the accompanying drawings. In particular, the invention extends to methods including the features described with respect to computer-implemented methods and / or computer programs; the invention extends to computer programs including the features described with respect to methods and / or computer programs; and the invention extends to computer-implemented methods including the features described with respect to methods and / or computer programs. Attached Figure Description

[0070] Some specific exemplary embodiments and aspects of the invention are described in the following description with reference to the accompanying drawings.

[0071] Figure 1 This is a schematic diagram of an embodiment of the method according to the present invention. Detailed Implementation

[0072] exist Figure 1 The logical steps of the method according to the present invention are described in the text.

[0073] In step 10, the temperature of the exhaust gases from the combustion turbine engine is continuously measured to obtain exhaust gas temperature values. The temperature values ​​can be obtained by measuring the temperature at a single location, or by calculating the average of various temperature values ​​obtained at different locations on the engine and / or the engine exhaust system. These temperature values ​​are stored in a memory during engine operation and are retrieved from the memory to perform the following steps according to the method of the invention.

[0074] The rotational speed of the engine shaft is also continuously measured and its value is stored in memory. The shaft is the main shaft of the engine. In particular, the shaft is the low-pressure shaft (or low-pressure valve spindle) of the engine. The value of the shaft rotational speed is stored in memory during engine operation and is retrieved from the memory to perform the steps of the method according to the invention.

[0075] In the first step 20, a temperature change index is calculated based on the temperature value of the exhaust gas. Specifically, the calculation can be the simple difference between two consecutive temperature values. Advantageously, the calculation is performed on two consecutive measured temperature values. Considering that temperature measurements are typically performed frequently, the temperature change index can be likened to the derivative of the exhaust gas temperature.

[0076] In the second step 21, the measured temperature value is compared with a predetermined emission temperature threshold. For example, in an aircraft APU, the temperature value can be compared with a threshold greater than 400 degrees Celsius.

[0077] In this second step 21, a temperature change index calculated from the temperature values ​​compared in the same step 21 is also compared with a first predetermined temperature change threshold and a second predetermined temperature change threshold to determine whether the temperature change index falls between these two thresholds. This allows filtering out any monitoring intervals where the temperature change index is very low or very high, thus indicating measurement error.

[0078] Other steps of the method according to the invention are performed only when both the first criterion (at least one temperature value is above a predetermined threshold) and the second criterion (the derivative of the temperature is within a predetermined range) are met at least at least one moment.

[0079] Once a pair of values ​​for the temperature and temperature change index at the same moment meet the first and second criteria respectively, proceed to step 22.

[0080] In step 22, a monitoring interval is defined. In this embodiment, the monitoring interval is an extended interval, which includes the time interval exactly before the first moment when the first and second criteria are met, and the time interval exactly after the last consecutive moment when the criteria and second criteria are met. In some cases, there may only be one moment when a pair of temperature and temperature change indicators respectively meet the first and second criteria, making the monitoring interval very short. In other cases, such conditions will be met at multiple consecutive moments (or measurement points), thus defining the duration of the monitoring interval and defining the duration of the monitoring interval by the amount of extension of the extended interval.

[0081] Extended intervals can include some seconds before and some seconds after the monitoring interval.

[0082] The program for implementing the method of the present invention includes a defined precursor variable. The precursor variable can take two values, such as, for example, a "true" value or a "false" value.

[0083] In step 23, the temperatures measured during the extended interval are processed to calculate the temperature difference between the highest and lowest temperature values ​​in the set. Before calculating this temperature difference, a filter can be applied to the temperature values ​​to exclude very extreme temperature values ​​that might simply result in errors in the temperature measurement.

[0084] Similarly, in step 23, the rotational speed values ​​of the engine shaft measured during the extended interval are processed to determine the minimum value among the set of rotational speed values.

[0085] In the subsequent step 24, the minimum speed value is compared with a first predetermined speed threshold and a second predetermined speed threshold to determine whether the minimum speed is within the range of values ​​determined by the first predetermined speed threshold and the second predetermined speed threshold.

[0086] Similarly, in step 24, the temperature difference is compared with a first predetermined temperature difference threshold.

[0087] If in step 24:

[0088] The minimum speed value is not between the first predetermined speed threshold and the second predetermined speed threshold, or

[0089] The temperature difference is below the temperature difference threshold.

[0090] The method then proceeds to step 25.

[0091] In step 25, the event counter is set to zero. The precursor variable is also set to "false".

[0092] Conversely, if in step 24:

[0093] The minimum speed value is between a first predetermined speed threshold and a second predetermined speed threshold, and

[0094] The temperature difference is higher than the temperature difference threshold.

[0095] The method then proceeds to step 26.

[0096] In step 26, the stored precursor value of the previous extended interval is retrieved. The stored value represents the previous occurrence (e.g., "true") (or absence—e.g., "false") of the dual condition observed in step 24 in the immediately preceding extended interval. More specifically, in a specific embodiment of the invention, the stored precursor value of the immediately preceding extended interval is retrieved.

[0097] If, in step 26, the stored precursor value indicates that the condition for triggering step 24 in the previous extended interval did not occur (in this embodiment, the precursor has the value "false"), then step 27 is executed.

[0098] In step 27, the precursor value of the current extended interval being analyzed is set to indicate that the condition for triggering step 24 of step 26 occurs in that extended interval; for example, it can be set to "true".

[0099] Similarly, in step 27, the event counter is set to 1.

[0100] If, in step 26, the stored precursor value indicates that the condition for step 24, which triggered step 26 in the previous extended interval, has occurred (e.g., "true"), then step 28 is executed.

[0101] In step 28, the event counter is set to a value higher than a predetermined threshold, for example, the event counter can be set to a value of 2.

[0102] After step 27 or step 28, step 29 is executed. In step 29, the value of the event counter is compared with the event threshold. For example, the event threshold could be 2. If the event counter is equal to or greater than the event threshold, step 30 is executed.

[0103] Step 30 corresponds to the triggering of an alarm signal. An alarm signal can be a signal to a computer, such as the engine controller. An alarm signal can also be a message to a person, such as a written message or indicator light to a pilot, maintenance team, or maintenance software. An alarm signal can indicate a deterioration in combustion conditions within a turbine engine. Alarm signals and the times they occur can be stored, allowing for the creation of an alarm signal history for further analysis of the number and frequency of occurrences during engine operation or even over multiple operating periods.

[0104] This invention is not limited to the specific embodiments disclosed herein as examples. The invention also includes other embodiments not explicitly described herein, which may include various combinations of the features described herein.

Claims

1. A method for identifying surge events in a turbine engine, the method comprising: a. Obtaining the temperature values ​​of the exhaust gases from the engine at multiple points in time during engine operation. b. Obtain the value of the temperature change index based on the temperature value of the emitted gas. c. When a first criterion and a second criterion are met at a given time, wherein the first criterion includes at least one temperature value higher than a predetermined emission temperature threshold and the second criterion includes at least one value of the temperature change index higher than a first predetermined temperature change threshold, then: i. Define the monitoring interval, wherein the monitoring interval is: The extension begins from the moment when both the first and second criteria are met. Extend the duration of continuous satisfaction of both the first and second criteria to the same length. ii. During the monitoring interval, a set of rotational speed values ​​of the engine shaft are obtained, the minimum value in the set of values ​​is determined, and the minimum speed value is compared with a first predetermined speed threshold. iii. During the monitoring interval, a set of temperature values ​​for the emitted gas are obtained; the temperature difference between the highest and lowest temperature values ​​in the set of values ​​is calculated; and the temperature difference is compared with a first predetermined temperature difference threshold. d. An alarm signal is triggered when the minimum speed value is lower than the first predetermined speed threshold and the temperature difference is higher than the predetermined temperature difference threshold in at least two separate monitoring intervals.

2. The method according to claim 1, characterized in that, An alarm signal is triggered only if the minimum speed value is lower than the first predetermined speed threshold and the temperature difference is higher than the predetermined temperature difference threshold in two consecutive extended intervals.

3. The method according to any one of claims 1 or 2, characterized in that, Step c is executed only if the temperature change index is also below the second predetermined temperature change threshold.

4. The method according to any one of claims 1 to 3, characterized in that, In step c, the monitoring interval is extended to include a time interval that is exactly before the first moment when the first criterion and the second criterion are satisfied.

5. The method according to any one of claims 1 to 4, characterized in that, In step c, the monitoring interval is extended to include a time interval that occurs exactly after the last consecutive occurrence of the condition that satisfies the first criterion and the second criterion within the monitoring interval.

6. The method according to any one of claims 4 or 5, characterized in that, The monitoring interval is extended between 2 and 30 seconds, for example, by 10 seconds.

7. The method according to any one of claims 1 to 6, characterized in that, In step d, the alarm signal is triggered only if the minimum speed value is also higher than the second predetermined speed threshold.

8. A computer-implemented method for identifying surge events in a turbine engine, the computer-implemented method comprising: a. Obtaining the temperature values ​​of the exhaust gases from the engine at multiple points in time during engine operation. b. Obtain the value of the temperature change index based on the temperature value of the emitted gas. c. When a first criterion and a second criterion are met at a given time, wherein the first criterion includes at least one temperature value higher than a predetermined emission temperature threshold and the second criterion includes at least one value of the temperature change index higher than a first predetermined temperature change threshold, then: i. Define the monitoring interval, wherein the monitoring interval is: The extension begins from the moment when both the first and second criteria are met. Extend the duration of continuous satisfaction of both the first and second criteria to the same length. ii. During the monitoring interval, a set of rotational speed values ​​of the engine shaft are obtained, the minimum value in the set of values ​​is determined, and the minimum speed value is compared with a first predetermined speed threshold. iii. During the monitoring interval, a set of temperature values ​​for the emitted gas are obtained; the temperature difference between the highest and lowest temperature values ​​in the set of values ​​is calculated; and the temperature difference is compared with a first predetermined temperature difference threshold. d. An alarm signal is triggered when the minimum speed value is lower than the first predetermined speed threshold and the temperature difference is higher than the predetermined temperature difference threshold in at least two separate monitoring intervals.

9. The computer implementation method according to claim 8, further characterized in that, Obtaining a set of values ​​for the rotational speed of the engine shaft and a set of values ​​for the temperature of the engine's exhaust gases includes retrieving values ​​from memory.

10. The computer implementation method according to any one of claims 8 or 9, characterized in that, Whenever the minimum speed value is lower than the predetermined speed threshold and the temperature difference is higher than the predetermined temperature difference threshold, the counter increments when the counter value is lower than 2, and when the counter value reaches 2, an alarm signal is triggered and the counter is reset to zero.

11. The computer implementation method according to claim 10, characterized in that, During the entire monitoring interval, whenever the minimum speed value is higher than the predetermined speed threshold or the temperature difference is lower than the predetermined temperature difference threshold, the counter is reset to zero.

12. A computer program comprising instructions for implementing the method according to any one of claims 1 to 11 when the program is run on a computer.

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