Aero-engine unit division decision-making method

Abstract

The invention provides an aero-engine unit division decision-making method which comprises the following steps: step 1, according to the independence and interchangeability of unit functions and the realizability of structures, performing hierarchical unit division on an engine main engine, and by permutation and combination of the units of different levels, performing unit division on the units of different levels; determining all selectable unit division schemes; 2, calculating the average fault frequency of each unit body in all the unit body division schemes available for selection in the whole life period; 3, according to the result of the step 2, calculating the average repair time and the spare part cost of all available unit division schemes; step 4, calculating an evaluation index of each alternative unit division scheme according to the average repair time and the spare part cost of all the alternative unit division schemes; and 5, according to the evaluation index of each optional unit body division scheme, selecting an optimal scheme for aero-engine unit body division.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engines, and in particular to a method for making decisions on the division of aero-engine units. Background Art

[0002] Aircraft engines are a highly complex, repairable multi-component system. As the heart of the aircraft, they are the focus of aviation maintenance and support. Advanced aircraft engines generally adopt a unit design, which can achieve fast and economical repair of faults by replacing engine units in the field. If the unit division scheme is unreasonable, it will seriously affect the engine support efficiency, leading to time-consuming and labor-intensive maintenance, high maintenance and support costs, and low aircraft availability.

[0003] At present, the traditional aircraft engine unit design method is dominated by empirical design, and there is a lack of a quantitative decision-making method for unit division based on different usage scenarios to quantify the parameters characterizing the aircraft engine guarantee benefits. Summary of the invention

[0004] In view of this, the present invention provides an aircraft engine unit division decision method to achieve the purpose of quantifying the impact of different unit division schemes on the mean repair time and spare parts cost under different usage scenarios.

[0005] The present invention provides the following technical solution: a method for making decisions on the division of aircraft engine units, comprising the following steps:

[0006] Step 1: Divide the engine main engine into hierarchical units according to the independence, interchangeability and structural feasibility of the unit functions, and determine all available unit division schemes by arranging and combining units at different levels;

[0007] Step 2, calculating the average number of failures of each unit body in all available unit body division schemes during the entire life cycle;

[0008] Step 3: Based on the result of step 2, calculate the average repair time and spare parts cost of all available unit division schemes;

[0009] Step 4: Calculate the evaluation index of each available unit division scheme according to the average repair time and spare parts cost of all available unit division schemes;

[0010] Step 5: Select the optimal plan for the division of the aircraft engine unit body according to the evaluation index of each available unit body division plan.

[0011] Furthermore, step 2 is specifically as follows:

[0012] According to the formula Calculate the average number of failures of each unit in all available unit division schemes during the entire life cycle, where FN ij is the number of failures that occur in the jth unit during its entire life cycle under the i-th partitioning scheme, λ ij is the failure rate of the jth unit under the i-th partitioning scheme, n i is the number of units in the ith partitioning scheme, T is the engine life, and MTBF is the mean time between failures.

[0013] Furthermore, the calculation of the average repair time of all available unit body partitioning schemes in step 3 includes the following steps:

[0014] According to the formula Calculate the average repair time for all available unit partitioning schemes, where MTTR i is the average repair time of the i-th partitioning scheme, MTTR ij is the average repair time of unit j under the i-th partitioning scheme.

[0015] Furthermore, the calculation of the spare parts costs of all available unit body division schemes in step 3 includes the following steps:

[0016] Based on the engine availability index and the average spare parts supply response time, the formula Calculate the spare parts satisfaction rate of all available unit division schemes, where P i is the spare parts satisfaction rate of the i-th partitioning scheme, A o is the engine availability index, T SR is the average supply response time for spare parts.

[0017] Furthermore, the calculation of the spare parts costs of all available unit body division schemes in step 3 further includes the following steps:

[0018] Based on the spare parts satisfaction rate of each optional unit division scheme and the cost of each unit in the corresponding unit division scheme after batch production, the formula Calculate the spare parts cost of each available unit partitioning scheme, where Cost i is the spare parts cost of the i-th partitioning scheme, Cost ij is the cost of batch production of unit j under the i-th partitioning scheme.

[0019] Further, step 4 includes:

[0020] By formula The average repair time of each available unit cell partitioning scheme is normalized, where is the normalized average repair time of the i-th partitioning scheme, minMTTR is the minimum average repair time among all partitioning schemes, and maxMTTR is the maximum average repair time among all partitioning schemes.

[0021] Furthermore, step 4 also includes:

[0022] By formula The spare parts cost of each available unit partitioning scheme is normalized, where is the normalized average repair time of the i-th partitioning scheme, minCost is the minimum spare part cost among all partitioning schemes, and maxCost is the maximum spare part cost among all partitioning schemes.

[0023] Furthermore, step 4 also includes:

[0024] By formula Calculate the evaluation index of each available unit body partitioning scheme, where V i is the evaluation index value of scheme i, α1 is the weight of mean repair time, and α2 is the weight of spare parts cost.

[0025] Furthermore, step 5 is specifically as follows:

[0026] Rank the evaluation indicators of all available unit body division schemes;

[0027] The unit body division scheme corresponding to the minimum value of the evaluation index of all available unit body division schemes is selected as the optimal scheme.

[0028] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted by the present invention include at least:

[0029] This decision-making method fully considers the coupling relationship between the structural failure rate, maintenance time, spare parts satisfaction rate, and availability that characterize the replacement efficiency of the field unit, and establishes a mathematical analytical expression for the mean repair time and spare parts cost. Through indicator weighting and normalization, a multi-objective comprehensive evaluation indicator model is established to obtain the comprehensive evaluation results of the maintenance support efficiency of multiple unit division schemes, and realize the decision-making of aircraft engine unit division;

[0030] This identification method uses weighting to achieve a multi-objective comprehensive evaluation of maintainability and cost indicators. The weight coefficient can be assigned according to the product's own characteristics, which can support the unit division decision-making work of serially developed aircraft engines in different usage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The present invention is a flowchart of an implementation method of an aircraft engine unit division decision method in an embodiment of the present invention.

[0033] Figure 2 It is a structural diagram of the unit body division of the engine in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0035] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0036] like Figure 1 As shown, the present invention provides an aircraft engine unit division decision method, comprising the following steps:

[0037] Step 1: Divide the engine main engine into hierarchical units according to the independence, interchangeability and structural feasibility of the unit functions, and determine all available unit division schemes by arranging and combining units at different levels;

[0038] Step 2, calculating the average number of failures of each unit body in all available unit body division schemes during the entire life cycle;

[0039] Step 3: Based on the result of step 2, calculate the average repair time and spare parts cost of all available unit division schemes;

[0040] Step 4: Calculate the evaluation index of each available unit division scheme according to the average repair time and spare parts cost of all available unit division schemes;

[0041] Step 5: Select the optimal plan for the division of the aircraft engine unit body according to the evaluation index of each available unit body division plan.

[0042] Specifically, step 2 is as follows:

[0043] According to the formula Calculate the average number of failures of each unit in all available unit division schemes during the entire life cycle, where FN ij is the number of failures that occur in the jth unit during its entire life cycle under the i-th partitioning scheme, λ ij is the failure rate of the jth unit under the i-th partitioning scheme, n i is the number of units in the ith partitioning scheme, T is the engine life, and MTBF is the mean time between failures.

[0044] Calculating the average repair time of all available unit body partitioning schemes in step 3 includes the following steps:

[0045] According to the formula Calculate the average repair time for all available unit partitioning schemes, where MTTR i is the average repair time of the i-th partitioning scheme, MTTR ij is the average repair time of unit j under the i-th partitioning scheme.

[0046] The calculation of the spare parts cost of all available unit division schemes in step 3 includes the following steps:

[0047] Based on the engine availability index and the average spare parts supply response time, the formula Calculate the spare parts satisfaction rate of all available unit division schemes, where P i is the spare parts satisfaction rate of the i-th partitioning scheme, A o is the engine availability index, T SR is the average supply response time for spare parts.

[0048] The calculation of the spare parts cost of all available unit body division schemes in step 3 also includes the following steps:

[0049] Based on the spare parts satisfaction rate of each optional unit division scheme and the cost of each unit in the corresponding unit division scheme after batch production, the formula Calculate the spare parts cost of each available unit partitioning scheme, where Cost i is the spare parts cost of the i-th partitioning scheme, Cost ij is the cost of batch production of unit j under the i-th partitioning scheme.

[0050] Step 4 includes:

[0051] By formula The average repair time of each available unit cell partitioning scheme is normalized, where is the normalized average repair time of the i-th partitioning scheme, minMTTR is the minimum average repair time among all partitioning schemes, and maxMTTR is the maximum average repair time among all partitioning schemes.

[0052] By formula The spare parts cost of each available unit partitioning scheme is normalized, where is the normalized average repair time of the i-th partitioning scheme, minCost is the minimum spare part cost among all partitioning schemes, and maxCost is the maximum spare part cost among all partitioning schemes.

[0053] Step 4 also includes:

[0054] By formula Calculate the evaluation index of each available unit body partitioning scheme, where Vi is the evaluation index value of scheme i, α1 is the weight of the mean repair time, and α2 is the weight of the spare parts cost.

[0055] Step 5 is as follows:

[0056] Rank the evaluation indicators of all available unit body division schemes;

[0057] The unit body division scheme corresponding to the minimum value of the evaluation index of all available unit body division schemes is selected as the optimal scheme.

[0058] It should be noted that the method of the present invention can be widely used to weigh and select various unit division schemes for aircraft engines and gas turbines, and provide technical support for real-time and rapid identification of whether the unit division scheme is reasonable, as well as the overall unit scheme design.

[0059] The following is a specific example for explanation:

[0060] Step 1: Divide the engine main engine into hierarchical units according to the independence, interchangeability and structural feasibility of the unit functions, and determine all available unit division schemes by arranging and combining units at different levels;

[0061] exist Figure 2In the engine structure, the main engine is divided into two levels: the first level contains 7 units, namely: fan, core engine, outer casing, low-pressure turbine, equipment module A, identification module B, and accessory casing; the second level contains 9 units, among which the fan is further divided into air intake casing and fan rotor, the core engine is divided into compressor, combustion chamber and high-pressure turbine, and the low-pressure turbine is divided into low-pressure turbine module A, low-pressure turbine module B, low-pressure turbine module C, and low-pressure turbine module D. Based on Figure 2 The options are shown in Table 1.

[0062] Table 1 Optional solutions

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069] In the table, “,” on the left and right are two different units, and “+” indicates the internal combination relationship of the same unit.

[0070] Step 2: Based on the engine life, mean time between failures, and failure probability of each unit during its life (which can be estimated using the similar product method or the reliability distribution result of the engine), calculate the average number of failures of each unit in all available unit division schemes during the entire life cycle:

[0071] according to Figure 2 The structure of each scheme is divided into units, and the units divided by each scheme are numbered from left to right to facilitate the calculation of unit faults and the display of results. For example, Scheme 1 divides 7 units into units. Figure 2 The structures from left to right are: fan, core engine, outer casing, low-pressure turbine, equipment module A, equipment module B, and accessory casing, which are recorded as unit 1, unit 2, unit 3, unit 4, unit 5, unit 6, and unit 7 respectively; Scheme 3 is divided into 8 units, according to Figure 2 The structures from left to right are: fan, compressor, combustion chamber + high-pressure turbine, outer casing, low-pressure turbine, equipment module A, equipment module B, accessory casing, which are respectively recorded as unit 1, unit 2, unit 3, unit 4, unit 5, unit 6, unit 7, and unit 8.

[0072] Taking the engine life, the mean time between failures of the main engine, and the failure probability of each unit during its life as input, the average number of failures of each unit during its entire life of 64 optional options is calculated. The detailed results are shown in Table 2.

[0073] Table 2 Average failure times of each unit in each scheme

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] Step 3: Based on the results of step 2, calculate the average repair time and spare parts cost of all available unit division schemes:

[0080] Based on the calculation results of the average number of failures of each unit body in each division scheme in Table 2 and the repair time of each unit body (similar product data or maintainability estimation value can be used), the average repair time MTTR of each division scheme is calculated. The detailed results are shown in Table 3.

[0081] Table 3 Average repair time of each solution

[0082]

[0083]

[0084] Based on the engine availability index and the average spare parts supply response time, the spare parts satisfaction rate of each division scheme is calculated. On this basis, combined with the cost estimate of each unit in the batch production stage and the number of unit failures in Table 2, the spare parts cost of each division scheme is obtained. The detailed results are shown in Table 4.

[0085] Table 4 Spare parts cost of each solution

[0086] plan Spare parts cost / 10,000 yuan plan Spare parts cost / 10,000 yuan plan Spare parts cost / 10,000 yuan Solution 1 1011.60 Solution 23 967.66 Scheme 45 888.82 Solution 2 932.76 Solution 24 682.56 Scheme 46 603.72 Solution 3 708.49 Solution 25 668.11 Scheme 47 589.27 Solution 4 724.72 Scheme 26 666.84 Scheme 48 588.00 Solution 5 971.52 Scheme 27 698.79 Scheme 49 619.95 Solution 6 987.66 Scheme 28 684.34 Scheme 50 605.50 Solution 7 1004.50 Scheme 29 683.07 Scheme 51 604.23 Solution 8 985.66 Scheme 30 906.82 Scheme 52 603.22 Solution 9 969.92 Scheme 31 891.08 Scheme 53 588.77 Solution 10 968.66 Scheme 32 889.82 Scheme 54 587.50 Solution 11 742.03 Scheme 33 590.87 Scheme 55 511.53 Solution 12 756.88 Scheme 34 604.72 Scheme 56 525.38 Solution 13 773.71 Scheme 35 622.55 Scheme 57 543.21 Solution 14 669.71 Scheme 36 594.46 Scheme 58 586.50 Solution 15 683.56 Scheme 37 608.31 Scheme 59 587.00 Scheme 16 701.39 Scheme 38 694.87 Scheme 60 603.23 Solution 17 892.68 Scheme 39 590.37 Scheme 61 524.38 Scheme 18 907.82 Scheme 40 604.22 Scheme 62 509.93 Solution 19 925.66 Scheme 41 622.05 Scheme 63 508.66 Solution 20 627.80 Scheme 42 550.31 Scheme 64 507.66 Solution 21 645.88 Scheme 43 665.84 - - Solution 22 629.15 Scheme 44 682.07 - -

[0087] Step 4: Calculate the evaluation index of each available unit division scheme based on the average repair time and spare parts cost of all available unit division schemes:

[0088] The average repair time and spare parts cost of the 64 solutions in Tables 3 and 4 are normalized, and the importance of the average repair time and spare parts cost is weighted according to the engine type and usage scenario. In this embodiment, the weighted values ​​of the average repair time and spare parts cost are both taken as 0.5. The evaluation index of each solution is calculated, and the specific results are shown in Table 5.

[0089] Table 5 Evaluation indicators of each scheme

[0090] plan Evaluation indicators plan Evaluation indicators plan Evaluation indicators Solution 1 0.5627 Solution 23 0.6324 Scheme 45 0.4915 Solution 2 0.4218 Solution 24 0.6615 Scheme 46 0.5206 Solution 3 0.5708 Solution 25 0.6529 Scheme 47 0.5032 Solution 4 0.5462 Scheme 26 0.6485 Scheme 48 0.5077 Solution 5 0.6451 Scheme 27 0.6369 Scheme 49 0.4960 Solution 6 0.7081 Scheme 28 0.6283 Scheme 50 0.4874 Solution 7 0.6778 Solution 29 0.6239 Scheme 51 0.4773 Solution 8 0.6534 Scheme 30 0.5125 Scheme 52 0.5671 Solution 9 0.6435 Scheme 31 0.5026 Scheme 53 0.5585 Solution 10 0.6334 Scheme 32 0.4982 Scheme 54 0.5515 Solution 11 0.6855 Scheme 33 0.5136 Scheme 55 0.4193 Solution 12 0.7473 Scheme 34 0.5274 Scheme 56 0.4330 Solution 13 0.7170 Scheme 35 0.5451 Scheme 57 0.4507 Solution 14 0.6013 Scheme 36 0.4765 Scheme 58 0.5474 Solution 15 0.6150 Scheme 37 0.4902 Scheme 59 0.5009 Scheme 16 0.6327 Scheme 38 0.5761 Scheme 60 0.4763 Solution 17 0.5042 Scheme 39 0.5601 Scheme 61 0.4263 Scheme 18 0.5192 Scheme 40 0.5739 Scheme 62 0.4177 Solution 19 0.5369 Scheme 41 0.5916 Scheme 63 0.4133 Solution 20 0.4281 Scheme 42 0.3356 Scheme 64 0.4065 Solution 21 0.4053 Scheme 43 0.6418 - - Solution 22 0.4764 Scheme 44 0.6172 - -

[0091] Step 5: Select the optimal solution for the division of the aircraft engine unit body according to the evaluation index of each available unit body division solution:

[0092] In the decision-making process, we hope that the average repair time and spare parts cost are as small as possible, so the solution that minimizes the evaluation index is the optimal solution. In this embodiment, the evaluation index value of solution 42 is 0.3356, which is the smallest among the 64 optional solutions and is the optimal solution. The engine is finally divided into 10 units, with 5 first-level units, namely the outer casing, low-pressure turbine, equipment module A, equipment module B, and accessory casing; and 5 second-level units, namely: air intake casing, fan rotor, compressor, combustion chamber, and high-pressure turbine.

[0093] 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 decision-making on the division of aircraft engine units, characterized in that: The following steps are involved: Step 1: Divide the engine main engine into hierarchical units according to the independence, interchangeability and structural feasibility of the unit functions, and determine all available unit division schemes by arranging and combining units at different levels; Step 2, calculating the average number of failures of each unit body in all available unit body division schemes during the entire life cycle; Step 3: Based on the result of step 2, calculate the average repair time and spare parts cost of all available unit division schemes; Step 4: Calculate the evaluation index of each available unit division scheme according to the average repair time and spare parts cost of all available unit division schemes; Step 5: Select the optimal plan for the division of the aircraft engine unit body according to the evaluation index of each available unit body division plan.

2. The aircraft engine unit division decision method according to claim 1, characterized in that: Step 2 is as follows: According to the formula Calculate the average number of failures of each unit in all available unit division schemes during the entire life cycle, where FN ij is the number of failures that occur in the jth unit during its entire life cycle under the i-th partitioning scheme, λ ij is the failure rate of the jth unit under the i-th partitioning scheme, n i is the number of units in the ith partitioning scheme, T is the engine life, and MTBF is the mean time between failures.

3. The aircraft engine unit division decision method according to claim 2, characterized in that: Calculating the average repair time of all available unit body partitioning schemes in step 3 includes the following steps: According to the formula Calculate the average repair time for all available unit partitioning schemes, where MTTR i is the average repair time of the i-th partitioning scheme, MTTR ij is the average repair time of unit j under the i-th partitioning scheme.

4. The aircraft engine unit division decision method according to claim 3, characterized in that: The calculation of the spare parts cost of all available unit division schemes in step 3 includes the following steps: Based on the engine availability index and the average spare parts supply response time, the formula Calculate the spare parts satisfaction rate of all available unit division schemes, where P i is the spare parts satisfaction rate of the i-th partitioning scheme, A o is the engine availability index, T SR is the average supply response time for spare parts.

5. The aircraft engine unit division decision method according to claim 4, characterized in that: The calculation of the spare parts cost of all available unit body division schemes in step 3 also includes the following steps: Based on the spare parts satisfaction rate of each optional unit division scheme and the cost of each unit in the corresponding unit division scheme after batch production, the formula Calculate the spare parts cost of each available unit partitioning scheme, where Cost i is the spare parts cost of the i-th partitioning scheme, Cost ij is the cost of batch production of unit j under the i-th partitioning scheme.

6. The aircraft engine unit division decision method according to claim 5, characterized in that: Step 4 includes: By formula The average repair time of each available unit cell partitioning scheme is normalized, where is the normalized average repair time of the i-th partitioning scheme, minMTTR is the minimum average repair time among all partitioning schemes, and maxMTTR is the maximum average repair time among all partitioning schemes.

7. The aircraft engine unit division decision method according to claim 6, characterized in that: Step 4 also includes: By formula The spare parts cost of each available unit partitioning scheme is normalized, where is the normalized average repair time of the i-th partitioning scheme, minCost is the minimum spare part cost among all partitioning schemes, and maxCost is the maximum spare part cost among all partitioning schemes.

8. The aircraft engine unit division decision method according to claim 7, characterized in that: Step 4 also includes: By formula Calculate the evaluation index of each available unit body partitioning scheme, where V i is the evaluation index value of scheme i, α1 is the weight of mean repair time, and α2 is the weight of spare parts cost.

9. The aircraft engine unit division decision method according to claim 8, characterized in that: Step 5 is as follows: Rank the evaluation indicators of all available unit body division schemes; The unit body division scheme corresponding to the minimum value of the evaluation index of all available unit body division schemes is selected as the optimal scheme.

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