A method for determining the test procedure of foreign object damage assessment for aircraft engines

Abstract

The present application provides a method for determining an aircraft engine foreign object damage assessment test program, the method comprising: dividing the aircraft engine foreign object damage assessment test program into four parts, namely, a large state test program, an encounter test program, a key assessment speed section test program, and a step test program; respectively determining the large state test program, the encounter test program, the key assessment speed section test program, and the step test program; combining the large state test program, the key assessment speed section test program, the step test program, and the encounter test program to obtain a complete engine foreign object damage assessment test program. The method for determining an aircraft engine foreign object damage assessment test program provided by the present application can meet the requirements of relevant standards, and the aircraft engine foreign object damage assessment test program formulated can be reasonable and accurate.

Description

Technical Field

[0001] The present application belongs to the field of aero-engine technology, and in particular relates to a method for determining a test procedure for foreign object damage assessment of an aero-engine. Background Art

[0002] During the use of aircraft engines, especially during takeoff and landing taxiing of aircraft equipped with them, small hard foreign objects such as sand, gravel, and small metals will inevitably be inhaled. During the inhalation process, these small hard objects will collide with the engine fan / compressor blades, causing damage to the blades. The damage caused by the impact of small hard foreign objects is called "foreign object damage" (FOD). After the fan / compressor blades are damaged by small hard foreign objects, they are generally not discovered immediately, and they need to continue to work for a period of time until the damage is detected and processed. During this period of time, the blades cannot be broken, which affects the safety of the engine. That is, the fan / compressor blades must have the ability to work safely for a period of time after being damaged by foreign objects, referred to as the ability to resist foreign object damage. GJB241A-2010 requires that the engine fan / compressor blades must have a certain ability to resist foreign object damage. After the blades are damaged by foreign objects with a prefabricated stress concentration coefficient Kt of not less than 3.0, they can continue to work safely for a certain period of time according to the prescribed procedures. It is also stipulated that before the engine is finalized and put into production, a test verification of the blade's ability to resist foreign object damage must be completed, which is called the foreign object damage test. The test requires pre-fabrication of foreign object damage notches with a Kt of not less than 3.0 on three fan / compressor blades. The damaged blades are installed on the engine and run for a period of time according to the prescribed procedures. If there are no signs of blade breakage or fracture, the engine is considered to meet the requirements for resisting foreign object damage.

[0003] In the engine FOD test, the key issue is what test procedure to use for assessment. There is no method for compiling the FOD assessment test procedure for aircraft engines in the existing technology, only the relevant requirements in GJB241A-2010. GJB241A-2010 requires that the engine with damaged blades be operated for at least 6 hours according to the test procedure of 4.4.2.1.3. 4.4.2.1.3 is a requirement for the endurance test procedure, which is a 300-hour endurance test procedure related to the accelerated flight mission, and a 25-hour step / encounter test procedure before and after. However, GJB241A-2010 requires that the test run be carried out in accordance with the endurance test run procedure, but the endurance test run procedure is a test run procedure of at least 300 hours, and the foreign object damage test run time is much less than 300 hours. It is impossible to directly use the endurance test run procedure to compile the foreign object damage assessment test run procedure; the endurance test run procedure includes step test run procedures, encounter test run procedures and test run procedures related to accelerated flight missions. The program types are complex and diverse, and it is impossible to directly compile the foreign object damage assessment test run procedure through time conversion. Summary of the invention

[0004] The purpose of the present application is to provide a method for determining a test procedure for foreign object damage assessment of an aircraft engine, so as to solve or alleviate at least one problem in the background technology.

[0005] The technical solution of the present application is: a method for determining a test program for foreign object damage assessment of an aircraft engine, the method comprising:

[0006] The aircraft engine FOD test procedure is divided into four parts, namely, large-state test procedure, encounter test procedure, key speed test procedure, and step test procedure.

[0007] Determine the large-state test run procedure, the encounter test run procedure, the key speed range test run procedure, and the step test run procedure respectively;

[0008] The large-state test program, the key assessment speed range test program, the step test program and the encounter test program are combined to obtain a complete engine foreign object damage assessment test program.

[0009] Furthermore, the process of determining the large-scale test run procedure includes:

[0010] a) Determine the time for the major state assessment in the engine FOD assessment test according to the major state working ratio required by the engine endurance test procedure and the engine FOD assessment test time;

[0011] b) According to the average relative proportion of the working time of each percentage speed segment within the working speed range of all engines, extract the distribution ratio of the working time of each percentage speed segment in the large-state speed segment, calculate the proportion of the working time of each percentage speed segment in the large-state speed segment relative to the entire large-state speed segment, and according to the large-state assessment time determined in step b above, obtain the working time of each percentage speed segment in the large-speed segment and determine the large-state test procedure.

[0012] Further, the process of determining the encounter test procedure includes:

[0013] According to the types and frequency of encounter tests required by the engine endurance test procedure, the types and frequency of each encounter test are converted according to the ratio of the endurance test assessment time and the foreign object damage assessment time, so as to determine the types and frequency of encounter tests in the foreign object damage test and determine the encounter test procedure.

[0014] Furthermore, when calculating the types and times of each encountered test run, a time less than 1 time shall be counted as 1 time.

[0015] Furthermore, the key assessment speed section is a working speed section where the vibration stress of the blade leading edge is relatively large, which is determined when the foreign object damage notch of the blade leading edge is prefabricated, and the test run procedure corresponding to the key assessment speed section is a foreign object damage key assessment speed section test run procedure;

[0016] The process of determining the key speed range test procedure is as follows:

[0017] a) First, compare the working time proportion of each engine in the key speed range, select the engine with the longest working time, and obtain the working time proportion of the key speed range of the engine and the speed proportion of each percentage in the key speed range;

[0018] b) Determine the assessment time of the key speed section in the engine FOD assessment test run according to the working time proportion of the key assessment speed section determined in step a and the engine FOD assessment test run time;

[0019] c) According to the proportion of each percentage speed in the key assessment speed section determined in step a, extract the working time distribution ratio of each percentage speed section in the key assessment speed section, calculate the working time ratio of each percentage speed section in the key assessment speed section relative to the entire key assessment speed section, and according to the assessment time of the key assessment speed section determined in step b, obtain the working time of each percentage speed section in the key assessment speed section, and determine the test run procedure for the key assessment speed section.

[0020] Furthermore, the process of determining the step-by-step commissioning procedure is as follows:

[0021] a) Based on the engine FOD assessment test time, remove the major status assessment time and the key speed section assessment time to obtain the step test assessment time;

[0022] b) For the average relative proportion of the working time of each percentage speed segment within the working speed range of all engines, eliminate the large-state speed segment and the key assessment speed segment, obtain the distribution ratio of the working time of each percentage speed segment in the remaining speed segment, calculate the distribution ratio of the working time of each percentage speed segment in the remaining speed segment, and obtain the assessment time of the remaining speed segment according to the step test assessment time determined in step a, and determine the step test procedure.

[0023] Furthermore, the percentage is 1%.

[0024] The method for determining the aircraft engine foreign object damage assessment test run procedure provided in this application can meet the requirements of GJB241A-2010, and the aircraft engine foreign object damage assessment test run procedure developed can be reasonable and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0026] Figure 1 The present invention is a flow chart of a method for determining the test procedure for foreign object damage assessment of an aircraft engine of the present application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0028] According to the requirements of the endurance test procedure in GJB241A-2010, the endurance test procedure consists of a step test procedure, an encounter test procedure and a test procedure related to the accelerated flight mission. The test procedure related to the accelerated mission also includes the test requirements for the intermediate thrust state and the state above the intermediate thrust (referred to as the large state).

[0029] This application is based on the formation and reasonable merger of endurance test procedures, and considers the key assessment speed section of the foreign object damage test, and divides the aircraft engine foreign object damage assessment test procedures into four parts, namely, large-state test procedures, encounter test procedures, key assessment speed section test procedures, and step test procedures. Among them, the step test procedure is composed of the step test procedures of the endurance test and the test procedures below the large state in the test procedures related to the accelerated flight mission, and is mainly determined by the test procedures below the large state in the test procedures related to the accelerated flight mission.

[0030] like Figure 1 As shown, the method for determining the aircraft engine foreign object damage assessment test program provided by the present application specifically includes the following process:

[0031] 1) Collect the working load spectra of each engine in field use, and count the working time of the load spectra according to a certain percentage of low-pressure speed, so as to obtain the relative proportion of the working time of each certain percentage of speed segment within the working speed range of each engine, and the average relative proportion of the working time of each certain percentage of speed segment within the working speed range of all engines;

[0032] In this embodiment of the present application, the percentage is 1%. In the following description, 1% is directly used for description.

[0033] 2) Determine the large-scale test run procedure, which includes:

[0034] 2.1) Determine the time for the major state assessment in the engine FOD assessment test according to the major state working ratio required by the engine endurance test procedure and the engine FOD assessment test time;

[0035] 2.2) According to the average relative proportion of the working time of each 1% speed segment within the working speed range of all engines, extract the distribution ratio of the working time of each 1% speed segment in the large-state speed segment, calculate the proportion of the working time of each 1% speed segment in the large-state speed segment relative to the entire large-state speed segment, and according to the large-state assessment time determined in step 2.1, obtain the working time of each 1% speed segment in the large-speed segment and determine the large-state test procedure.

[0036] 3) Determine the encounter test procedure

[0037] For the types and frequencies of encounter tests required by the engine endurance test procedure, the types and frequencies of encounter tests are converted according to the ratio of the endurance test assessment time and the foreign object damage assessment time. If the number is less than 1, it will be calculated as 1. In this way, the types and frequencies of encounter tests in the foreign object damage test and the encounter test procedure are determined.

[0038] 4) Determine the test procedure for the speed range that is the focus of the assessment

[0039] In the design of the foreign object damage test plan, there is a key assessment speed section. This speed section is the working speed section with greater vibration stress on the leading edge of the blade, which is determined when the foreign object damage notch on the leading edge of the blade is prefabricated. This speed section is the key assessment procedure for foreign object damage.

[0040] 4.1) First, compare the working time proportion of each engine in the key speed range, select the engine with the longest working time, and obtain the working time proportion of the key speed range of the engine and the 1% speed proportion in the key speed range;

[0041] 4.2) According to the working time proportion of the key speed section determined in 4.1) and the engine foreign object damage assessment test time, determine the assessment time of the key speed section in the engine foreign object damage assessment test;

[0042] 4.3) According to the proportion of each 1% speed in the key assessment speed section determined in 4.1), extract the working time distribution ratio of each 1% speed section in the key assessment speed section, calculate the working time ratio of each 1% speed section in the key assessment speed section relative to the entire key assessment speed section, and according to the assessment time of the key assessment speed section determined in step 4.2, obtain the working time of each 1% speed section in the key assessment speed section, and determine the test run procedure for the key assessment speed section.

[0043] 5) Determine the step-by-step commissioning procedure

[0044] 5.1) Based on the engine foreign object damage assessment test time, remove the large state assessment time and the key assessment speed section assessment time to obtain the step test assessment time;

[0045] 5.2) For the average relative proportion of the working time of each 1% speed segment within the working speed range of all engines, eliminate the large-state speed segment and the key assessment speed segment, obtain the distribution ratio of the working time of each 1% speed segment in the remaining speed segment, calculate the distribution ratio of the working time of each 1% speed segment in the remaining speed segment, and according to the step test assessment time determined in 5.1), obtain the assessment time of the remaining speed segment and determine the step test procedure.

[0046] 6) Combine the large-state test procedure, the key speed range test procedure, the step test procedure and the encounter test procedure to obtain a complete engine foreign object damage assessment test procedure.

[0047] The method for determining the aircraft engine foreign object damage assessment test run procedure provided in this application can meet the requirements of GJB241A-2010, and the aircraft engine foreign object damage assessment test run procedure developed can be reasonable and accurate.

[0048] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining a test run procedure for foreign object damage assessment of an aircraft engine, characterized in that: The method comprises: The aircraft engine FOD test procedure is divided into four parts, namely, large-state test procedure, encounter test procedure, key speed test procedure, and step test procedure. Determine the large-state test procedure, encounter test procedure, key speed range test procedure, and step test procedure respectively, among which: The process of the large-scale commissioning program includes: a) Determine the time for the major state assessment in the engine FOD assessment test according to the major state working ratio required by the engine endurance test procedure and the engine FOD assessment test time; b) According to the average relative proportion of the working time of each percentage speed segment within the working speed range of all engines, extract the distribution ratio of the working time of each percentage speed segment in the large-state speed segment, calculate the proportion of the working time of each percentage speed segment in the large-state speed segment relative to the entire large-state speed segment, obtain the working time of each percentage speed segment in the large-state speed segment according to the large-state assessment time determined in step b, and determine the large-state test program; The process of the encounter test run procedure includes: For the encounter test types and times required by the engine endurance test procedure, calculate the encounter test types and times according to the ratio of the endurance test assessment time to the foreign object damage assessment time, so as to determine the encounter test types and times in the foreign object damage test and determine the encounter test procedure; The key assessment speed section is a working speed section where the vibration stress of the blade leading edge is relatively large when the notch of foreign object damage at the leading edge of the blade is prefabricated. The test procedure corresponding to the key assessment speed section is the foreign object damage key assessment speed section test procedure. The process of the key assessment speed section test procedure is as follows: c) First, compare the working time proportion of each engine in the key speed range, select the engine with the longest working time, and obtain the working time proportion of the key speed range of the engine and the speed proportion of each percentage in the key speed range; d) Determine the assessment time of the key assessment speed section in the engine foreign object damage assessment test run according to the working time proportion of the key assessment speed section determined in step c and the engine foreign object damage assessment test run time; e) According to the proportion of each percentage speed in the key assessment speed section determined in step c, extract the distribution ratio of the working time of each percentage speed section in the key assessment speed section, calculate the working time ratio of each percentage speed section in the key assessment speed section relative to the entire key assessment speed section, obtain the working time of each percentage speed section in the key assessment speed section according to the assessment time of the key assessment speed section determined in step d, and determine the test run procedure for the key assessment speed section; The process of the step-by-step commissioning procedure is as follows: f) Based on the engine foreign object damage assessment test time, remove the large state assessment time and the key assessment speed section assessment time to obtain the step test assessment time; g) For the average relative proportion of the working time of each percentage speed segment within the working speed range of all engines, remove the large state speed segment and the key assessment speed segment, obtain the distribution ratio of the working time of each percentage speed segment in the remaining speed segment, calculate the distribution ratio of the working time of each percentage speed segment in the remaining speed segment, and obtain the assessment time of the remaining speed segment according to the step test assessment time determined in step f, and determine the step test procedure; The large-state test program, the key assessment speed range test program, the step test program and the encounter test program are combined to obtain a complete engine foreign object damage assessment test program.

2. The method for determining the aircraft engine foreign object damage assessment test program according to claim 1, characterized in that: When calculating the types and times of each test run, any test run less than one time will be counted as one time.

3. The method for determining the aircraft engine foreign object damage assessment test program according to claim 2, characterized in that: The percentage is 1%.

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