A method for controlling afterburner fuel supply of an aviation turbofan engine

Abstract

The present application belongs to the technical field of afterburner fuel design for aircraft engines, and specifically relates to an afterburner fuel control method for an aircraft turbofan engine. A non-reference nozzle throat area afterburner fuel correction coefficient is designed to correct the fuel supply amount of the afterburner combustion chamber under the reference nozzle throat area based on the reference afterburner fuel law, so as to obtain the real-time fuel supply amount of the afterburner combustion chamber, so that the fuel supply to the afterburner combustion chamber can be made consistent with the changing trend of the nozzle throat area, thereby avoiding the problems of rich fuel combustion, ablation of afterburner components, increased fuel consumption rate, lean fuel combustion, and thrust not achieving the optimal design.

Description

Technical Field

[0001] The present application belongs to the technical field of afterburner fuel supply design for aircraft engines, and specifically relates to a method for controlling afterburner fuel supply for aircraft turbofan engines. Background Art

[0002] The afterburner fuel supply law of aviation turbofan engines is usually designed according to the equal excess air coefficient within the full envelope. The air flow rate at the engine inlet is divided by the excess air coefficient to get the air flow rate used for combustion. The total fuel flow rate available for combustion is calculated according to the air flow rate required for each kilogram of fuel burned. The fuel flow rate required by the main combustion chamber is subtracted to get the fuel supply to the afterburner combustion chamber.

[0003] However, in the actual operation of aviation turbofan engines, since the engine inlet air flow cannot be obtained directly, the relationship between the fuel supply to the afterburner and the engine inlet temperature and the compressor outlet pressure is usually given based on the correspondence between the engine inlet air flow and the engine inlet temperature and the compressor outlet pressure, and then the afterburner is supplied with fuel according to the engine inlet temperature and the compressor outlet pressure.

[0004] The design of the fuel supply to the afterburner according to the engine inlet temperature and the compressor outlet pressure is well suited for the case where the nozzle throat area of ​​the aviation turbofan engine remains unchanged. When the nozzle throat area changes, there will be deviations, for example:

[0005] When the nozzle throat area becomes smaller, under the same low-pressure conversion speed conditions, the engine inlet air flow will decrease, and the amount of fuel required for the afterburner combustion chamber should be reduced, but the compressor outlet pressure increases. Based on the afterburner fuel supply law of aviation turbofan engines, the fuel supply to the afterburner combustion chamber is increased according to the engine inlet temperature and compressor outlet pressure, resulting in problems such as rich fuel combustion, afterburner component ablation, and increased fuel consumption rate.

[0006] When the nozzle throat area becomes larger, under the same low-pressure converted speed conditions, the engine inlet air flow will increase, and the amount of fuel required for the afterburner combustion chamber should increase, but the compressor outlet pressure decreases. Based on the afterburner fuel supply law of aviation turbofan engines, the fuel supply to the afterburner combustion chamber is reduced according to the engine inlet temperature and compressor outlet pressure, resulting in problems such as lean combustion and thrust not achieving the optimal design.

[0007] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0008] The purpose of the present application is to provide an aviation turbofan engine afterburner fuel supply control method to overcome or alleviate at least one of the known technical deficiencies.

[0009] The technical solution of this application is:

[0010] A method for controlling afterburner fuel supply of an aviation turbofan engine, comprising:

[0011] Step 1: Calculate the engine inlet air flow rate and its compressor outlet pressure as the engine inlet temperature changes under the reference nozzle throat area;

[0012] Step 2: Under the reference nozzle throat area, design according to the equal residual gas coefficient to obtain the fuel supply amount of the afterburner combustion chamber under the reference nozzle throat area as the reference afterburner fuel supply law;

[0013] Step 3: Divide the fuel supply amount of the afterburner under the reference nozzle throat area by the corresponding compressor outlet pressure to obtain the ratio of the fuel supply amount of the afterburner under the reference nozzle throat area to the compressor outlet pressure;

[0014] Step 4: within the engine design range, adjust the nozzle throat area to a non-reference nozzle throat area, and calculate the engine inlet air flow and its compressor outlet pressure as the engine inlet temperature changes under the non-reference nozzle throat area;

[0015] Step 5: Under the non-standard nozzle throat area, design according to the equal residual gas coefficient to obtain the fuel supply of the afterburner under the non-standard nozzle throat area;

[0016] Step 6: Divide the fuel supply amount of the afterburner under the non-reference nozzle throat area by the corresponding compressor outlet pressure to obtain the ratio of the fuel supply amount of the afterburner under the non-reference nozzle throat area to the compressor outlet pressure;

[0017] Step 7, dividing the ratio of the fuel supply amount of the afterburner combustion chamber under the non-reference nozzle throat area to the compressor outlet pressure by the ratio of the fuel supply amount of the afterburner combustion chamber under the reference nozzle throat area to the compressor outlet pressure, to obtain the non-reference nozzle throat area afterburner fuel supply correction coefficient at different engine inlet temperatures;

[0018] Step 8. Based on the benchmark afterburner fuel supply law and the engine inlet temperature and compressor outlet pressure, the fuel supply amount of the afterburner combustion chamber under the benchmark nozzle throat area is obtained, and then the afterburner fuel supply correction coefficient of the corresponding non-benchmark nozzle throat area is used for correction to obtain the real-time fuel supply amount of the afterburner combustion chamber.

[0019] Optionally, in the above-mentioned aviation turbofan engine afterburner fuel control method, in step one, the engine overall performance calculation model is used for calculation.

[0020] Optionally, in the above-mentioned aviation turbofan engine afterburner fuel supply control method, in step 2, the design is performed according to an equal residual gas coefficient, wherein the residual gas coefficient is 1.1 to 1.15.

[0021] Optionally, in the above-mentioned aviation turbofan engine afterburner fuel control method, in step four, the engine overall performance calculation model is used for calculation.

[0022] Optionally, in the above-mentioned aviation turbofan engine afterburner fuel supply control method, in step four, the difference between adjacent different non-reference nozzle throat areas is 1%.

[0023] Optionally, in the above-mentioned aviation turbofan engine afterburner fuel supply control method, in step five, the design is performed according to an equal residual gas coefficient, wherein the residual gas coefficient is 1.1 to 1.15.

[0024] This application has at least the following beneficial technical effects:

[0025] Provided is an aviation turbofan engine afterburner fuel supply control method, which designs an afterburner fuel supply correction coefficient based on a non-reference nozzle throat area, corrects the fuel supply amount of an afterburner combustion chamber under a reference nozzle throat area based on a reference afterburner fuel supply law, and obtains a real-time fuel supply amount of the afterburner combustion chamber, so that the fuel supply to the afterburner combustion chamber can be made consistent with the change trend of the nozzle throat area, thereby avoiding the problems of rich fuel combustion, afterburner component ablation, increased fuel consumption rate, lean fuel combustion, and thrust not achieving optimal design. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of an aviation turbofan engine afterburner fuel supply control method provided in an embodiment of the present application;

[0027] Figure 2 It is a schematic diagram of a curve of the ratio of the fuel supply volume of the afterburner to the compressor outlet pressure Wfa / P3 under the reference nozzle throat area provided in an embodiment of the present application, which varies with the engine inlet temperature T2;

[0028] Figure 3 It is a schematic diagram comparing a curve of the ratio of the fuel supply to the afterburner to the compressor outlet pressure Wfa / P3 under a non-reference nozzle throat area and changes with the engine inlet temperature T2 when the nozzle throat area becomes smaller or larger provided in an embodiment of the present application, and a curve of the ratio of the fuel supply to the afterburner to the compressor outlet pressure Wfa / P3 under a reference nozzle throat area and changes with the engine inlet temperature T2.

[0029] In order to better illustrate the present embodiment, some contents of the drawings may be omitted, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0030] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0031] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0032] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0033] A method for controlling afterburner fuel supply of an aviation turbofan engine, such as Figure 1 shown.

[0034] Step 1: Calculate the engine inlet air flow rate and its compressor outlet pressure as the engine inlet temperature changes under the reference nozzle throat area. The engine overall performance calculation model can be used for calculation.

[0035] Step 2: Under the reference nozzle throat area, design according to the equal residual gas coefficient to obtain the fuel supply of the afterburner combustion chamber under the reference nozzle throat area, which is used as the reference afterburner fuel supply law. The specific calculation can be referred to as follows:

[0036] Wfa=Wa1 / a / b-Wfb;

[0037] in,

[0038] Wfa is the fuel supply to the afterburner;

[0039] Wa1 is the engine inlet air flow rate;

[0040] a is the residual gas coefficient, ranging from 1.1 to 1.15;

[0041] b is the air flow required for burning each kilogram of fuel;

[0042] Wfb is the fuel flow required by the main combustion chamber.

[0043] Step 3: Divide the fuel supply of the afterburner under the reference nozzle throat area by the corresponding compressor outlet pressure to obtain the ratio of the fuel supply of the afterburner under the reference nozzle throat area to the compressor outlet pressure.

[0044] The ratio of the fuel supply volume of the afterburner to the compressor outlet pressure Wfa / P3 under the reference nozzle throat area varies with the engine inlet temperature T2, as shown in Figure 2 shown.

[0045] Step 4: Within the engine design range, adjust the nozzle throat area to a non-reference nozzle throat area, and calculate the engine inlet air flow and its compressor outlet pressure as the engine inlet temperature changes under the non-reference nozzle throat area. The engine overall performance calculation model can be used for calculation.

[0046] The difference between adjacent non-reference nozzle throat areas is 1%.

[0047] Step 5. Under the non-reference nozzle throat area, design according to the equal residual gas coefficient to obtain the fuel supply of the afterburner under the non-reference nozzle throat area. The specific calculation can be carried out according to step 2.

[0048] Step 6: Divide the fuel supply amount of the afterburner under the non-reference nozzle throat area by the corresponding compressor outlet pressure to obtain the ratio of the fuel supply amount of the afterburner under the non-reference nozzle throat area to the compressor outlet pressure.

[0049] When the nozzle throat area becomes smaller or larger, the curve of the ratio of the fuel supply volume of the afterburner to the compressor outlet pressure Wfa / P3 under the non-reference nozzle throat area, which changes with the engine inlet temperature T2, is compared with the curve of the ratio of the fuel supply volume of the afterburner to the compressor outlet pressure Wfa / P3 under the reference nozzle throat area, which changes with the engine inlet temperature T2, as shown in the figure. Figure 3 shown.

[0050] Step 7. Divide the ratio of the fuel supply volume of the afterburner under the non-reference nozzle throat area to the compressor outlet pressure by the ratio of the fuel supply volume of the afterburner under the reference nozzle throat area to the compressor outlet pressure to obtain the non-reference nozzle throat area afterburner fuel supply correction coefficient at different engine inlet temperatures.

[0051] Step 8. Based on the benchmark afterburner fuel supply law and the engine inlet temperature and compressor outlet pressure, the fuel supply amount of the afterburner combustion chamber under the benchmark nozzle throat area is obtained, and then the afterburner fuel supply correction coefficient of the corresponding non-benchmark nozzle throat area is used for correction to obtain the real-time fuel supply amount of the afterburner combustion chamber.

[0052] The aviation turbofan engine afterburner fuel control method disclosed in the above embodiment is designed to use a non-reference nozzle throat area afterburner fuel correction coefficient to correct the fuel supply amount of the afterburner combustion chamber under the reference nozzle throat area based on the reference afterburner fuel supply law, so as to obtain the real-time fuel supply amount of the afterburner combustion chamber, so that the fuel supply to the afterburner combustion chamber can be made consistent with the changing trend of the nozzle throat area, thereby avoiding the problems of rich fuel combustion, ablation of afterburner components, increased fuel consumption rate, lean fuel combustion, and thrust not achieving the optimal design.

[0053] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for controlling afterburner fuel supply of an aviation turbofan engine, characterized in that: include: Step 1: Calculate the engine inlet air flow rate and its compressor outlet pressure as the engine inlet temperature changes under the reference nozzle throat area; Step 2: Under the reference nozzle throat area, design according to the equal residual gas coefficient to obtain the fuel supply amount of the afterburner combustion chamber under the reference nozzle throat area as the reference afterburner fuel supply law; Step 3: Divide the fuel supply amount of the afterburner under the reference nozzle throat area by the corresponding compressor outlet pressure to obtain the ratio of the fuel supply amount of the afterburner under the reference nozzle throat area to the compressor outlet pressure; Step 4: within the engine design range, adjust the nozzle throat area to a non-reference nozzle throat area, and calculate the engine inlet air flow and its compressor outlet pressure as the engine inlet temperature changes under the non-reference nozzle throat area; Step 5: Under the non-standard nozzle throat area, design according to the equal residual gas coefficient to obtain the fuel supply of the afterburner under the non-standard nozzle throat area; Step 6: Divide the fuel supply amount of the afterburner under the non-reference nozzle throat area by the corresponding compressor outlet pressure to obtain the ratio of the fuel supply amount of the afterburner under the non-reference nozzle throat area to the compressor outlet pressure; Step 7, dividing the ratio of the fuel supply amount of the afterburner combustion chamber under the non-reference nozzle throat area to the compressor outlet pressure by the ratio of the fuel supply amount of the afterburner combustion chamber under the reference nozzle throat area to the compressor outlet pressure, to obtain the non-reference nozzle throat area afterburner fuel supply correction coefficient at different engine inlet temperatures; Step 8. Based on the benchmark afterburner fuel supply law and the engine inlet temperature and compressor outlet pressure, the fuel supply amount of the afterburner combustion chamber under the benchmark nozzle throat area is obtained, and then the afterburner fuel supply correction coefficient of the corresponding non-benchmark nozzle throat area is used for correction to obtain the real-time fuel supply amount of the afterburner combustion chamber.

2. The aviation turbofan engine afterburner fuel supply control method according to claim 1, characterized in that: In step one, the engine overall performance calculation model is used for calculation.

3. The aviation turbofan engine afterburner fuel supply control method according to claim 2, characterized in that: In step 2, the design is performed according to the equal residual gas coefficient, wherein the residual gas coefficient is 1.1 to 1.

15.

4. The aviation turbofan engine afterburner fuel supply control method according to claim 3, characterized in that: In step 4, the engine overall performance calculation model is used for calculation.

5. The aviation turbofan engine afterburner fuel supply control method according to claim 4, characterized in that: In step 4, the difference between adjacent non-reference nozzle throat areas is 1%.

6. The aviation turbofan engine afterburner fuel supply control method according to claim 5, characterized in that: In step five, the design is performed according to the equal residual gas coefficient, wherein the residual gas coefficient is 1.1 to 1.15.

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