Automatic diagnosis method and system for failure of grouped thermocouples of aero-engine

Abstract

The invention discloses an aero-engine group thermocouple failure automatic diagnosis method and system, and belongs to the technical field of aero-engines, the aero-engine group thermocouple failure automatic diagnosis method comprises the steps of numbering each thermocouple in a thermocouple group, and positioning based on the numbered thermocouples. Through the combined judgment of a single thermocouple and a group of thermocouples, the failure condition of the thermocouples can be automatically detected; after the average temperature expression is obtained based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the other numbered thermocouples and the temperature data expression of the reference thermocouple, rapid positioning of the failed thermocouple can be realized based on the change of the average temperature expression.

Description

Technical Field

[0001] The invention belongs to the technical field of aero-engines, and in particular relates to an automatic diagnosis method and system for failure of grouped thermocouples of an aero-engine. Background Art

[0002] A typical aircraft engine consists of an air inlet, compressor, combustion chamber, gas turbine, power turbine and other components. In order to monitor the operating status of the engine, sensors are arranged on different components. Among them, the power turbine inlet temperature is an important parameter that characterizes the operating status of the engine. During flight, in order to ensure the service life and reliability of the engine, the inlet temperature must be maintained within the operating limit range. The pilot will adjust the operating status according to the inlet temperature: if the inlet temperature is close to the limit value, the operating status must be reduced to lower the inlet temperature, keep it at a healthy level, and maintain the service life of the engine; if the inlet temperature is low, the operating status can be increased to meet the pilot's demand for high power.

[0003] Aircraft engines are highly complex machines. The inlet section of the power turbine is a high-temperature, high-pressure, unsteady, non-uniform flow field. The temperature at different positions on the section (45 section) is not consistent. Therefore, in order to objectively grasp the state of the engine and accurately measure the temperature, the power turbine inlet temperature is currently mainly measured by grouped thermocouples, and the average temperature output by the grouped thermocouples is used as the measured temperature. However, since the thermocouples work in high-temperature, high-pressure, unsteady, non-uniform flow fields for a long time, they are subjected to the combined effects of high temperature and alternating stress. Therefore, there is a greater risk of ablation or fracture of a certain T45 thermocouple. When a thermocouple is ablated or fractured, the corresponding output is the average value of the remaining thermocouples as the output temperature. However, once a thermocouple fails, the output average value will inevitably change, such as damaging the thermocouple. The temperature measured by the thermocouple is the maximum value. When it is damaged, the average temperature of the system output decreases, indicating that the pilot's available power increases. However, once the pilot pushes up the engine status, the actual temperature will be higher than the displayed temperature, which may cause the engine to overheat and damage the engine life and flight safety. On the contrary, the measured value of the damaged thermocouple is smaller, and the average output temperature will increase, indicating that the engine status is improved and the pilot's available power is reduced, but the actual temperature will be lower than the displayed temperature. During the process of pushing up the engine status, the limit value will be triggered in advance, limiting the engine's power output, resulting in the need for greater power in some emergency situations but not being available, which also endangers flight safety. Based on this, it is necessary to design a solution that can quickly locate the position of the failed thermocouple when the thermocouple fails and formulate strategies in time. Summary of the invention

[0004] The object of the present invention is to provide an automatic diagnosis method and system for failure of grouped thermocouples of aircraft engines, so as to solve the problem of locating failed thermocouples proposed in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: an automatic diagnosis method for failure of a group of thermocouples in an aircraft engine, comprising:

[0006] Number each thermocouple in the thermocouple group, and obtain temperature data of all numbered thermocouples;

[0007] Calculate a first average value of the temperature data of all numbered thermocouples in the thermocouple group and a second average value of the thermocouple group after removing the temperature data of any numbered thermocouple;

[0008] The failure of the thermocouple group is determined based on the difference between the second average value and the first average value and the rate of change of the first average value. When the thermocouple group fails, the failed thermocouple in the thermocouple group is located and includes:

[0009] Obtain the temperature data expression of each thermocouple based on the thermocouple number;

[0010] Select any numbered thermocouple from the thermocouple group as a reference thermocouple, and obtain a difference expression between the temperature data expression of the remaining numbered thermocouples and the temperature expression of the reference thermocouple;

[0011] The average temperature expression of the thermocouple group is obtained based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature data expression of the reference thermocouple; and the failed thermocouple in the thermocouple group is located based on the average temperature expression.

[0012] Further, based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature data expression of the reference thermocouple, an average temperature expression of the thermocouple group is obtained; and locating the failed thermocouple in the thermocouple group based on the average temperature expression includes:

[0013] Based on the temperature data expression of the reference thermocouple and the difference expression between the temperature expressions of the remaining numbered thermocouples and the temperature data expression of the reference thermocouple, a first expression of the average temperature of the thermocouple group under all numbered thermocouples and a second expression of the average temperature of the thermocouple group after removing any numbered thermocouple are obtained;

[0014] The difference between the first expression and the second expression is obtained to obtain the average temperature change expression of the thermocouple group;

[0015] The failed thermocouple in the thermocouple group is located based on the average temperature change expression.

[0016] Further, the positioning of the failed thermocouples in the thermocouple group based on the average temperature change expression includes:

[0017] Substitute the temperature data of the thermocouple into the average temperature change expression for evaluation. When the evaluation result is greater than the third set value, locate and remove the numbered thermocouple as a failed thermocouple.

[0018] Further, the determining of the failure condition of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value includes:

[0019] The difference is compared with a set value, and when the difference is less than a first set value, it is determined that the thermocouple group is not failed.

[0020] Further, the determining of the failure condition of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value also includes:

[0021] When the difference is greater than the first set value, the absolute value of the change rate of the first average value is compared with the set value, and when the absolute value of the change rate of the first average value is greater than the second set value, it is determined that the thermocouple group has failed.

[0022] Further, the thermocouple with the number corresponding to the minimum value of the temperature data of the thermocouples in the thermocouple group is selected as the reference thermocouple.

[0023] Furthermore, the temperature data of each thermocouple is expressed as T45 -n , where n is the thermocouple number, and n is an integer greater than or equal to 1.

[0024] Furthermore, the third setting value is 4.

[0025] Furthermore, the first set value is 6° C., and the second set value is 20%.

[0026] On the other hand, the present application discloses an automatic diagnosis system for failure of grouped thermocouples of aircraft engines, comprising:

[0027] An acquisition module, which is configured to number each thermocouple in the thermocouple group and obtain temperature data of all numbered thermocouples;

[0028] A calculation module, configured to calculate a first average value of temperature data of all numbered thermocouples in the thermocouple group and a second average value of the thermocouple group after removing temperature data of any numbered thermocouple;

[0029] A positioning module is configured to determine the failure of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value, and when the thermocouple group fails, locate the failed thermocouple number in the thermocouple group and include:

[0030] Obtain the temperature data expression of each thermocouple based on the thermocouple number;

[0031] Select any numbered thermocouple from the thermocouple group as a reference thermocouple, and obtain a difference expression between the temperature data expression of the remaining numbered thermocouples and the temperature expression of the reference thermocouple;

[0032] The average temperature expression of the thermocouple group is obtained based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature expression of the reference thermocouple; and the failed thermocouple number in the thermocouple group is located based on the average temperature expression.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present application can automatically detect the failure of thermocouples through combined judgment of single thermocouples and grouped thermocouples, and when the thermocouple fails, after obtaining the average temperature expression based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature data expression of the reference thermocouple, the failed thermocouple can be quickly located based on the change of the average temperature expression. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of the application method;

[0036] Figure 2 It is a schematic diagram of the engine structure and the power turbine inlet;

[0037] Figure 3 Schematic diagram of the measurement system. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Reference Figure 3 , is a schematic diagram of the measurement system, where the thermocouple sensor is arranged at Figure 2The 45 section position in the figure, and the thermocouple group is arranged in a circular array on the power turbine section (45 section), and the average temperature value output by the thermocouple group is used as the output temperature of the thermocouple group to realize temperature monitoring. However, since the thermocouple group operates in an environment of high temperature, high pressure and non-uniform flow field of non-fixed length for a long time, it is subjected to the combined effect of high temperature and alternating stress. Therefore, the risk of a single thermocouple ablation and fracture is relatively large. When a thermocouple ablates or fractures, the thermocouple fails, and the T45 junction box transmits the average value of the remaining intact thermocouples to the engine test system as the output temperature. However, the failure of a thermocouple is bound to cause a change in the output temperature. In some examples, if the temperature of the area measured by the failed thermocouple is higher, that is, the temperature output by the thermocouple is higher, when the thermocouple is damaged, the average temperature output by the thermocouple group drops. Low. From the parameter display, it seems that the engine status is reduced and the pilot's available power is increased. However, once the pilot pushes up the engine status, the actual temperature will be higher than the displayed temperature, which may cause engine overheating and damage engine life and flight safety. In other examples, if the temperature of the area measured by the faulty thermocouple is low, that is, the temperature output by the thermocouple is low, when the thermocouple is damaged, the average temperature output by the thermocouple group increases, indicating that the engine status is improved and the pilot's available power is reduced. The actual temperature will be lower than the displayed temperature. During the engine status push-up process, the T45 limit value will be triggered in advance, limiting the engine's power output, resulting in the need for greater power in some emergency situations but not being available, which also endangers flight safety. Based on the above problems, the present application provides an automatic diagnosis method for failure of grouped thermocouples of aircraft engines, with reference to Figure 1 , the above method comprises:

[0040] S100: numbering each thermocouple in the thermocouple group, and obtaining temperature data of all numbered thermocouples;

[0041] S200: Calculate a first average value of temperature data of all numbered thermocouples in the thermocouple group and a second average value of the thermocouple group after removing temperature data of any numbered thermocouple;

[0042] S300: Determine the failure of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value. When the thermocouple group fails, locate the number of the failed thermocouple in the thermocouple group and include:

[0043] Obtain the temperature data expression of each thermocouple based on the thermocouple number;

[0044] Select any numbered thermocouple from the thermocouple group as a reference thermocouple, and obtain a difference expression between the temperature data expression of the remaining numbered thermocouples and the temperature expression of the reference thermocouple;

[0045] Obtaining an average temperature expression of the thermocouple group based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature expression of the reference thermocouple; and

[0046] Locate the failed thermocouple number in the thermocouple group based on the average temperature expression.

[0047] In some embodiments, determining the failure status of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value includes:

[0048] The difference is compared with a set value, and when the difference is less than a first set value, it is determined that the thermocouple group is not failed.

[0049] Further, judging the failure condition of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value also includes:

[0050] When the difference is greater than the first set value, the absolute value of the change rate of the first average value is compared with the set value, and when the absolute value of the change rate of the first average value is greater than the second set value, it is determined that the thermocouple group has failed.

[0051] In some embodiments, in step S300, the temperature data expression of each thermocouple is obtained based on the thermocouple, that is, a code is given to the temperature data of each thermocouple. For example, the temperature data of each thermocouple is expressed as T45. -n , where n is the number of the thermocouple, and n is an integer greater than or equal to 1. Correspondingly, taking the thermocouple numbered 1 as the reference thermocouple as an example, the difference expression between the temperature data expression of any other numbered thermocouple and the temperature expression of the reference thermocouple corresponds to T45 -n -T45 -1 , correspondingly, the above expression based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature expression of the reference thermocouple obtains the average temperature expression of the thermocouple group; and

[0052] The method of locating the failed thermocouple number in the thermocouple group based on the average temperature expression specifically includes:

[0053] Locating the failed thermocouple in a thermocouple group based on the average temperature expression includes:

[0054] Based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature expression of the reference thermocouple, a first expression of the average temperature of the thermocouple group under all numbered thermocouples and a second expression of the average temperature of the thermocouple group after removing any numbered thermocouple are obtained;

[0055] The difference between the first expression and the second expression is obtained to obtain the average temperature change expression of the thermocouple group;

[0056] The failed thermocouple in the thermocouple group is located based on the average temperature change expression.

[0057] Furthermore, locating the failed thermocouple in the thermocouple group based on the average temperature change expression includes:

[0058] Substitute the temperature data of the thermocouple into the average temperature change expression for evaluation. When the evaluation result is greater than the third set value, locate and remove the numbered thermocouple as a failed thermocouple.

[0059] The following is an explanation of the above method using a measurement system including four thermocouples, and the measured temperatures of the four thermocouples are recorded as T45-1, T45-2, T45-3, and T45-4, respectively, that is, T45-1, T45-2, T45-3, and T45-4 correspond to the temperatures measured by thermocouples No. 1 to 4, respectively, and T45-1 is the minimum value, and satisfies T45-1<T45-2<T45-3<T45-4, and the differences between T45-2, T45-3, and T45-4 and T45-1 are calculated accordingly:

[0060] Δ 2-1 =T45 -2 -T45 -1

[0061] Δ 3-1 =T45 -3 -T45 -1

[0062] Δ 4-1 =T45 -4 -T45 -1

[0063] When a thermocouple fails, the remaining three of the four thermocouples will automatically average and output signals. At this time, T45 has the characteristics of sudden jump and maintenance. Assuming that under normal conditions, the average value of the four thermocouples is T45AVG,

[0064]

[0065] After one thermocouple fails, the average value of the remaining three thermocouples is T45 (AVG). Taking the failure of T45-1 as an example, at this time

[0066]

[0067] At this time, the thermocouple failure judgment logic includes two types: T45 absolute value change and slope change. The thermocouple failure is determined only when both are met. The details are as follows:

[0068] when At this time, no matter how the slope of T45AVG changes, the system will judge that the T45 thermocouple is normal and will not take any action.

[0069] when And T45 AVG When the absolute value of the slope change is greater than 20%, it is determined that the thermocouple group is damaged, and the subsequent failed thermocouple positioning step is entered accordingly.

[0070] The steps to locate a failed thermocouple are as follows:

[0071] First, based on the difference between T45-2, T45-3, T45-4 and T45-1 obtained from the above calculation, the calculation formula of the average temperature TAVG of the above thermocouple group is rewritten. At this time, T45-1+T45-2+T45-3+T45-4=Δ2-1+Δ3-1+Δ4-1+3T45-1. Substituting the above formula into the calculation formula of T45AVG, the new calculation formula of T45AVG is obtained as follows:

[0072]

[0073] At this time, the failure judgment logic of thermocouple No. 1 is as follows:

[0074] Assume that thermocouple No. 1 fails.

[0075] At this time, when the absolute value of the change in T45(AVG) compared to T45AVG is less than the set value (for example, 4°C) and lasts for the set time (for example, 2s), that is, And if it lasts for 2s, it can be determined that thermocouple No. 1 has failed.

[0076] The failure judgment logic of thermocouple No. 2 is similar to that of thermocouple No. 1:

[0077] When the No. 2 thermocouple fails, T45 (AVG) Compared with T4 5AVG The change is At this time And if it lasts for 2s, it can be determined that thermocouple No. 2 has failed.

[0078] The failure judgment logic of thermocouple No. 3 is similar to that of thermocouple No. 1:

[0079] When the No. 3 thermocouple fails, T45 (AVG) Compared with T45 AVG The change is At this time And if it lasts for 2s, it can be determined that thermocouple No. 3 has failed.

[0080] The failure judgment logic of thermocouple No. 4 is similar to that of thermocouple No. 1:

[0081] When the No. 4 thermocouple fails, T45 (AVG) Compared with T45 AVG The change is At this time And if it lasts for 2s, it can be determined that thermocouple No. 3 has failed.

[0082] On the other hand, the present application discloses an automatic diagnosis system for failure of grouped thermocouples of aircraft engines, comprising:

[0083] An acquisition module, which is configured to number each thermocouple in the thermocouple group and obtain temperature data of all numbered thermocouples;

[0084] A calculation module, configured to calculate a first average value of temperature data of all numbered thermocouples in the thermocouple group and a second average value of the thermocouple group after removing temperature data of any numbered thermocouple;

[0085] A positioning module is configured to determine the failure of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value, and when the thermocouple group fails, locate the failed thermocouple number in the thermocouple group and include:

[0086] Obtain the temperature data expression of each thermocouple based on the thermocouple number;

[0087] Select any numbered thermocouple from the thermocouple group as a reference thermocouple, and obtain a difference expression between the temperature data expression of the remaining numbered thermocouples and the temperature expression of the reference thermocouple;

[0088] Obtaining an average temperature expression of the thermocouple group based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature expression of the reference thermocouple; and

[0089] Locate the failed thermocouple number in the thermocouple group based on the average temperature expression.

[0090] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatic diagnosis method for failure of grouped thermocouples of aircraft engines, characterized in that: include: Number each thermocouple in the thermocouple group, and obtain temperature data of all numbered thermocouples; Calculate a first average value of the temperature data of all numbered thermocouples in the thermocouple group and a second average value of the thermocouple group after removing the temperature data of any numbered thermocouple; The failure of the thermocouple group is determined based on the difference between the second average value and the first average value and the rate of change of the first average value. When the thermocouple group fails, the failed thermocouple in the thermocouple group is located and includes: Obtain the temperature data expression of each thermocouple based on the thermocouple number; Select any numbered thermocouple from the thermocouple group as a reference thermocouple, and obtain a difference expression between the temperature data expression of the remaining numbered thermocouples and the temperature expression of the reference thermocouple; Based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature data expression of the reference thermocouple, the average temperature expression of the thermocouple group is obtained, and the failed thermocouple in the thermocouple group is located based on the average temperature expression.

2. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 1, characterized in that: Based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature data expression of the reference thermocouple, the average temperature expression of the thermocouple group is obtained, and the failed thermocouple in the thermocouple group is located based on the average temperature expression, including: Based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature expression of the reference thermocouple, a first expression of the average temperature of the thermocouple group under all numbered thermocouples and a second expression of the average temperature of the thermocouple group after removing any numbered thermocouple are obtained; The difference between the first expression and the second expression is obtained to obtain the average temperature change expression of the thermocouple group; The failed thermocouple in the thermocouple group is located based on the average temperature change expression.

3. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 2, characterized in that: The method of locating the failed thermocouple in the thermocouple group based on the average temperature change expression includes: Substitute the temperature data of the thermocouple into the average temperature change expression for evaluation. When the evaluation result is greater than the third set value, locate and remove the numbered thermocouple as a failed thermocouple.

4. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 1, characterized in that: The determining of the failure condition of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value comprises: The difference is compared with a set value, and when the difference is less than a first set value, it is determined that the thermocouple group is not failed.

5. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 4, characterized in that: The determining of the failure condition of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value further includes: When the difference is greater than the first set value, the absolute value of the change rate of the first average value is compared with the set value, and when the absolute value of the change rate of the first average value is greater than the second set value, it is determined that the thermocouple group has failed.

6. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 1, characterized in that: The thermocouple with the minimum value of the temperature data of the thermocouples in the thermocouple group is selected as the reference thermocouple.

7. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 1, characterized in that: The temperature data of each thermocouple is expressed as T45 -n , where n is the thermocouple number, and n is an integer greater than or equal to 1.

8. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 3, characterized in that: The third setting value is 4.

9. The method for automatically diagnosing failure of a group of thermocouples in an aircraft engine according to claim 5, characterized in that: The first setting value is 6° C., and the second setting value is 20%.

10. An automatic diagnosis system for failure of grouped thermocouples of aircraft engines, characterized by: include: An acquisition module, which is configured to number each thermocouple in the thermocouple group and obtain temperature data of all numbered thermocouples; A calculation module, configured to calculate a first average value of temperature data of all numbered thermocouples in the thermocouple group and a second average value of the thermocouple group after removing temperature data of any numbered thermocouple; A positioning module is configured to determine the failure of the thermocouple group based on the difference between the second average value and the first average value and the change rate of the first average value, and when the thermocouple group fails, locate the number of the failed thermocouple in the thermocouple group and include: Obtain the temperature data expression of each thermocouple based on the thermocouple number; Select any numbered thermocouple from the thermocouple group as a reference thermocouple, and obtain a difference expression between the temperature data expression of the remaining numbered thermocouples and the temperature expression of the reference thermocouple; The average temperature expression of the thermocouple group is obtained based on the temperature data expression of the reference thermocouple and the difference expression between the temperature data expressions of the remaining numbered thermocouples and the temperature expression of the reference thermocouple; and the failed thermocouple number in the thermocouple group is located based on the average temperature expression.

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