A method and apparatus for regulating a nozzle of a turbofan engine in a throttled state

Abstract

The application belongs to the technical field of engine control, and particularly relates to a turbofan engine throttling state nozzle adjusting method and device. The method comprises the following steps: S1, obtaining a first low-pressure conversion speed given value when the engine is in a nozzle closing state, and a second low-pressure conversion speed given value corresponding to an intermediate state of the engine; S2, discretely obtaining a plurality of low-pressure conversion speed control amounts; S3, for each low-pressure conversion speed control amount, determining a first nozzle throat area when a fan stability margin is the smallest, and a second nozzle throat area when an outer-inner content pressure ratio is 1; S4, selecting a larger value of the two nozzle throat areas as a nozzle throat area adjusting amount under the low-pressure conversion speed control amount; and S5, adjusting the nozzle throat area according to a corresponding relationship between the low-pressure conversion speed control amount and the nozzle throat area adjusting amount. The application improves the thrust of the engine in a throttling state, reduces fuel consumption, and increases the flight range and combat radius of an airplane.

Description

Technical Field

[0001] This application belongs to the field of engine control technology, specifically relating to a method and device for adjusting the nozzle throttling state of a turbofan engine. Background Technology

[0002] Considering the differences from axisymmetric nozzle design, the two-dimensional nozzle requires a large amount of engine bypass air for cooling. When matching the whole engine, the internal pressure ratio of the engine main unit needs to be redesigned to ensure that the two-dimensional nozzle can work normally and not be burned under afterburning conditions.

[0003] Currently, the nozzle adjustment plan for the throttling state of turbofan engines equipped with two-dimensional nozzles still follows the original engine adjustment plan, without optimizing and matching the nozzle adjustment plan.

[0004] Throttling state typically refers to the state of the engine before reaching its intermediate operating speed. Taking the low-pressure equivalent speed (LPS) of 100% as the intermediate state as an example, throttling state refers to the process from the set LPS (e.g., 50%) to the LPS reaching 100%. During throttling state, the nozzle throat area usually shrinks to a fixed area under a certain engine LPS condition and no longer adjusts. Figure 2 As shown at node A, conversely, after the engine drops from the intermediate state to the throttle state, the nozzle throat area initially remains unchanged, then gradually increases at point A. According to the characteristic change trend of the engine, as the engine power gradually decreases from the intermediate and afterburner states, the internal pressure ratio gradually increases with the decrease in engine power, that is, the internal pressure ratio gradually exceeds the design state, and the lower the state, the greater the deviation. The greater the mixing loss between the two-dimensional nozzle cooling air and the main flow channel, the greater the thrust loss and fuel consumption rate increase, which seriously affects the fuel consumption index of the aircraft during subsonic cruise and reduces the aircraft's range and combat radius. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a method and apparatus for adjusting the nozzle in the throttling state of a turbofan engine. Based on existing nozzle throat area adjustment methods, the nozzle throat area is further reduced to decrease the external internal pressure ratio.

[0006] The first aspect of this application provides a method for adjusting the nozzle under throttling conditions in a turbofan engine, mainly including:

[0007] Step S1: Obtain the first low-pressure converted speed setpoint when the engine nozzle closes, and the second low-pressure converted speed setpoint corresponding to the engine intermediate state.

[0008] Step S2: Discretize multiple low-pressure converted speed control quantities within the speed range formed by the first low-pressure converted speed setpoint and the second low-pressure converted speed setpoint;

[0009] Step S3: For each low-pressure converted speed control quantity, determine the first nozzle throat area when the fan stability margin is minimized under the selected low-pressure converted speed control quantity, and determine the second nozzle throat area when the internal and external pressure ratio is 1 under the selected low-pressure converted speed control quantity.

[0010] Step S4: Select the larger value between the first nozzle throat area and the second nozzle throat area as the nozzle throat area adjustment amount under the selected low-pressure converted speed control amount, and form each nozzle throat area adjustment amount corresponding to each low-pressure converted speed control amount.

[0011] Step S5: When the engine enters the throttling state, adjust the nozzle throat area according to the real-time low-pressure converted speed and the correspondence between the low-pressure converted speed control amount and the nozzle throat area adjustment amount.

[0012] Preferably, in step S2, the speed range is discretized using a 5% speed range as the step size.

[0013] Preferably, in step S3, determining the area of ​​the first nozzle throat includes:

[0014] Step S31: Under the selected low-pressure converted speed control condition, determine the fan surge margin adjustment amount based on the difference between the fan stability margin corresponding to the nozzle throat area after the original engine nozzle is closed and the minimum stability margin for stable fan operation.

[0015] Step S32: Under the selected low-pressure converted speed control conditions, when the nozzle throat area of ​​the original engine changes by 1% after the nozzle is closed, determine the change in fan surge margin.

[0016] Step S33: Determine the adjustment amount of the first nozzle throat area based on the fan surge margin adjustment amount and the fan surge margin change amount;

[0017] Step S34: Subtract the adjustment amount of the first nozzle throat area from the original nozzle throat area of ​​the engine to form the first nozzle throat area.

[0018] Preferably, in step S3, determining the throat area of ​​the second nozzle includes:

[0019] Step T31: Under the selected low-pressure converted speed control condition, determine the overall engine external internal pressure ratio adjustment amount based on the external internal pressure ratio corresponding to the nozzle throat area after the original engine nozzle is closed.

[0020] Step T32: Under the selected low-pressure converted speed control conditions, when the nozzle throat area of ​​the original engine changes by 1% after the nozzle is closed, determine the change in the overall internal and external pressure ratio of the engine.

[0021] Step T33: Determine the second nozzle throat area adjustment amount based on the overall machine outer and inner pressure ratio adjustment amount and the overall machine outer and inner pressure ratio change amount;

[0022] Step T34: Subtract the adjustment amount of the second nozzle throat area from the original nozzle throat area of ​​the engine to form the second nozzle throat area.

[0023] Preferably, in step S5, the nozzle throat area adjustment amount corresponding to the real-time low-pressure converted speed is determined by interpolation.

[0024] The second aspect of this application provides a nozzle adjustment device for the throttling state of a turbofan engine, mainly comprising:

[0025] The design parameter acquisition module is used to acquire the first low-pressure converted speed setpoint when the engine closes the nozzle, and the second low-pressure converted speed setpoint corresponding to the intermediate state of the engine.

[0026] The low-pressure converted speed discretization module is used to discretize multiple low-pressure converted speed control quantities within the speed range formed by the first low-pressure converted speed setpoint and the second low-pressure converted speed setpoint.

[0027] The nozzle throat area calculation module is used to determine the first nozzle throat area when the fan stability margin is minimized under the selected low-pressure converted speed control value for each low-pressure converted speed control value, and to determine the second nozzle throat area when the inner and outer pressure ratio is 1 under the selected low-pressure converted speed control value.

[0028] The nozzle throat area selection module is used to select the larger value between the first nozzle throat area and the second nozzle throat area as the nozzle throat area adjustment amount under the selected low-pressure converted speed control amount, thereby forming each nozzle throat area adjustment amount corresponding to each low-pressure converted speed control amount.

[0029] The nozzle throat adjustment module is used to adjust the nozzle throat area according to the correspondence between the low-pressure converted speed control amount and the nozzle throat area adjustment amount when the engine enters the throttling state, based on the real-time low-pressure converted speed.

[0030] Preferably, in the low-pressure converted speed discretization module, the speed range is discretized using a 5% speed range as the step size.

[0031] Preferably, the nozzle throat area calculation module includes:

[0032] The fan surge margin adjustment unit is used to determine the fan surge margin adjustment amount based on the difference between the fan stability margin corresponding to the nozzle throat area after the original engine nozzle is closed and the minimum stability margin for stable fan operation, under the selected low-pressure converted speed control conditions.

[0033] The fan surge margin change determination unit is used to determine the fan surge margin change when the nozzle throat area changes by 1% after the original engine nozzle retraction under the selected low-pressure converted speed control conditions.

[0034] The first nozzle throat area adjustment calculation unit is used to determine the first nozzle throat area adjustment amount based on the fan surge margin adjustment amount and the fan surge margin change amount.

[0035] The first nozzle throat area calculation unit is used to subtract the adjustment amount of the first nozzle throat area from the original nozzle throat area after the engine nozzle retracts, so as to form the first nozzle throat area.

[0036] Preferably, the nozzle throat area calculation module includes:

[0037] The unit for determining the overall engine's external and internal pressure ratio adjustment is used to determine the overall engine's external and internal pressure ratio adjustment amount based on the external and internal pressure ratio corresponding to the original engine's nozzle throat area after nozzle retraction, under the selected low-pressure converted speed control conditions.

[0038] The unit for determining the change in the overall internal and external pressure ratio is used to determine the change in the overall internal and external pressure ratio when the area of ​​the nozzle throat after the original engine closes the nozzle changes by 1% under the selected low-pressure converted speed control conditions.

[0039] The second nozzle throat area adjustment calculation unit is used to determine the second nozzle throat area adjustment amount based on the overall machine outer and inner pressure ratio adjustment amount and the overall machine outer and inner pressure ratio change amount.

[0040] The second nozzle throat area calculation unit is used to subtract the adjustment amount of the second nozzle throat area from the original nozzle throat area after the engine nozzle retracts, so as to form the second nozzle throat area.

[0041] Preferably, the nozzle throat adjustment module includes an interpolation unit for determining the nozzle throat area adjustment amount corresponding to the real-time low-pressure converted rotational speed through interpolation.

[0042] This application improves the thrust of the engine under throttling conditions, reduces fuel consumption, and increases the aircraft's flight range and combat radius. Attached Figure Description

[0043] Figure 1This is a flowchart of a preferred embodiment of the turbofan engine throttling state nozzle adjustment method of this application.

[0044] Figure 2 This is a schematic diagram of the optimized nozzle throat area adjustment plan. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0046] This application provides a method and apparatus for adjusting the nozzle in the throttling state of a turbofan engine. It optimizes the existing nozzle throat area adjustment scheme and further reduces the nozzle throat area in the engine throttling state, thereby reducing the internal and external pressure ratio.

[0047] The first aspect of this application provides a method for adjusting the nozzle under throttling conditions in a turbofan engine, such as... Figure 1 As shown, it mainly includes:

[0048] Step S1: Obtain the first low-pressure converted speed setpoint when the engine nozzle closes, and the second low-pressure converted speed setpoint corresponding to the engine intermediate state.

[0049] refer to Figure 2 The process of the engine's low-pressure equivalent speed increasing from 50% to 100% (relative value) is defined as a throttling state. In the original plan, the nozzle throat area began to shrink at point B and remained unchanged after point C. In step S1 of this application, the low-pressure equivalent speed corresponding to point B is the first low-pressure equivalent speed setpoint n. 1r,min The engine's intermediate state, i.e., the low-pressure equivalent speed of 100%, corresponds to the second low-pressure equivalent speed setpoint n. 1r,max .

[0050] Step S2: Discretize multiple low-pressure converted speed control quantities within the speed range formed by the first low-pressure converted speed setpoint and the second low-pressure converted speed setpoint.

[0051] In some alternative implementations, the speed range is discretized using a 5% speed range as a step size, and the discretized low-pressure converted speed control quantity is set to n. 1r,1 n 1r,2 ...n 1r,X Starting point n 1r,1 The first low-pressure converted speed setpoint n 1r,min .

[0052] Step S3: For each low-pressure converted speed control quantity, determine the first nozzle throat area when the fan stability margin is minimized under the selected low-pressure converted speed control quantity, and determine the second nozzle throat area when the internal and external pressure ratio is 1 under the selected low-pressure converted speed control quantity.

[0053] Although this application further reduces the nozzle throat area based on the original nozzle throat area control, this reduction will decrease the fan stability margin. Therefore, in step S3, this application needs to further calculate the first nozzle throat area based on the fan stability margin to constrain the adjustment of the nozzle throat area in subsequent steps. On the other hand, as the nozzle throat area gradually decreases, the engine's external internal pressure ratio may be less than 1.0. This will cause the combustion gas to backflow into the two-dimensional nozzle cooling gas passage, reducing the structural reliability of the two-dimensional nozzle cooling passage. Therefore, it is necessary to ensure that the external internal pressure ratio is not lower than 1.0. Thus, in step S3, this application needs to further calculate the second nozzle throat area based on the overall engine external internal pressure ratio of 1 to constrain the adjustment of the nozzle throat area in subsequent steps.

[0054] In some alternative implementations, in step S3, the area A of the first nozzle throat is determined. 8,XF include:

[0055] Step S31: Under the selected low-pressure converted speed control condition, calculate the fan stability margin sm based on the original engine nozzle throat area A8 after nozzle retraction. f,X Minimum stability margin sm for stable fan operation f,Xmin The difference is used to determine the fan surge margin adjustment amount △sm f :

[0056] △sm f =sm f,X -sm f,Xmin .

[0057] Step S32: Under the selected low-pressure converted speed control conditions, when the nozzle throat area changes by 1% after the original engine nozzle retraction, determine the change in fan surge margin Δsm. f (A8)

[0058] Step S33: Based on the fan surge margin adjustment amount △sm f and the change in the fan surge margin Δsm f (A8) Determine the adjustment amount △A for the throat area of ​​the first nozzle. 8,XF :

[0059] △A 8,XF =△sm f / △sm f (A8)

[0060] Step S34: Based on the original nozzle throat area A8 after the engine nozzle converges, subtract the adjustment amount △A of the first nozzle throat area. 8,XF The first nozzle throat area A is formed. 8,XF :

[0061] A 8,XF =A8-△A 8,XF .

[0062] In some alternative implementations, in step S3, the throat area A of the second nozzle is determined. 8,XP include:

[0063] Step T31: Under the selected low-pressure converted speed control condition, based on the external and internal pressure ratio P corresponding to the original engine nozzle throat area A8 after nozzle retraction. 16 / 6,X Determine the adjustment amount △P of the overall machine's internal and external pressure ratio. 16 / 6 :

[0064] △P 16 / 6 =P 16 / 6,X -1.

[0065] Step T32: Under the selected low-pressure converted speed control conditions, when the nozzle throat area changes by 1% after the original engine nozzle retraction, determine the change in the overall internal and external pressure ratio ΔP. 16 / 6 (A8)

[0066] Step T33: Based on the overall machine's internal and external pressure ratio adjustment amount △P 16 / 6 and the change in the overall internal and external pressure ratio ΔP 16 / 6 (A8) Determine the adjustment amount △A for the throat area of ​​the second nozzle. 8,XP :

[0067] △A 8,XP =△P 16 / 6 / △P 16 / 6 (A8)

[0068] Step T34: Based on the original nozzle throat area A8 after the engine nozzle converges, subtract the adjustment amount △A of the second nozzle throat area. 8,XP This forms the second nozzle throat area A.8,XP :

[0069] A 8,XP =A8-△A 8,XP .

[0070] Step S4: Select the larger value between the first nozzle throat area and the second nozzle throat area as the nozzle throat area adjustment amount A under the selected low-pressure converted speed control amount. 8,X This forms the conversion speed control quantity n with each low-pressure unit. 1r,X Corresponding adjustment amount A of each nozzle throat area 8,X .

[0071] Step S5: When the engine enters the throttling state, adjust the nozzle throat area according to the real-time low-pressure converted speed and the correspondence between the low-pressure converted speed control amount and the nozzle throat area adjustment amount.

[0072] With n 1r,X A corresponding to rotational speed 8,X As a new engine nozzle throat area adjustment scheme, it can reduce the internal pressure ratio of the engine under throttling conditions, thereby reducing the mixing loss of the two-dimensional nozzle, improving the overall thrust, and reducing the overall fuel consumption rate. A schematic diagram of the optimized nozzle throat area adjustment scheme is shown below. Figure 2 As shown by the dashed line.

[0073] In some alternative implementations, in step S5, the nozzle throat area adjustment amount corresponding to the real-time low-pressure converted speed is determined by interpolation.

[0074] The second aspect of this application provides a turbofan engine throttling state nozzle adjustment device corresponding to the above method, mainly comprising:

[0075] The design parameter acquisition module is used to acquire the first low-pressure converted speed setpoint when the engine closes the nozzle, and the second low-pressure converted speed setpoint corresponding to the intermediate state of the engine.

[0076] The low-pressure converted speed discretization module is used to discretize multiple low-pressure converted speed control quantities within the speed range formed by the first low-pressure converted speed setpoint and the second low-pressure converted speed setpoint.

[0077] The nozzle throat area calculation module is used to determine the first nozzle throat area when the fan stability margin is minimized under the selected low-pressure converted speed control value for each low-pressure converted speed control value, and to determine the second nozzle throat area when the inner and outer pressure ratio is 1 under the selected low-pressure converted speed control value.

[0078] The nozzle throat area selection module is used to select the larger value between the first nozzle throat area and the second nozzle throat area as the nozzle throat area adjustment amount under the selected low-pressure converted speed control amount, thereby forming each nozzle throat area adjustment amount corresponding to each low-pressure converted speed control amount.

[0079] The nozzle throat adjustment module is used to adjust the nozzle throat area according to the correspondence between the low-pressure converted speed control amount and the nozzle throat area adjustment amount when the engine enters the throttling state, based on the real-time low-pressure converted speed.

[0080] In some alternative implementations, the speed range is discretized in the low-pressure converted speed discretization module with a step size of 5% of the speed range.

[0081] In some optional embodiments, the nozzle throat area calculation module includes:

[0082] The fan surge margin adjustment unit is used to determine the fan surge margin adjustment amount based on the difference between the fan stability margin corresponding to the nozzle throat area after the original engine nozzle is closed and the minimum stability margin for stable fan operation, under the selected low-pressure converted speed control conditions.

[0083] The fan surge margin change determination unit is used to determine the fan surge margin change when the nozzle throat area changes by 1% after the original engine nozzle retraction under the selected low-pressure converted speed control conditions.

[0084] The first nozzle throat area adjustment calculation unit is used to determine the first nozzle throat area adjustment amount based on the fan surge margin adjustment amount and the fan surge margin change amount.

[0085] The first nozzle throat area calculation unit is used to subtract the adjustment amount of the first nozzle throat area from the original nozzle throat area after the engine nozzle retracts, so as to form the first nozzle throat area.

[0086] In some optional embodiments, the nozzle throat area calculation module includes:

[0087] The unit for determining the overall engine's external and internal pressure ratio adjustment is used to determine the overall engine's external and internal pressure ratio adjustment amount based on the external and internal pressure ratio corresponding to the original engine's nozzle throat area after nozzle retraction, under the selected low-pressure converted speed control conditions.

[0088] The unit for determining the change in the overall internal and external pressure ratio is used to determine the change in the overall internal and external pressure ratio when the area of ​​the nozzle throat after the original engine closes the nozzle changes by 1% under the selected low-pressure converted speed control conditions.

[0089] The second nozzle throat area adjustment calculation unit is used to determine the second nozzle throat area adjustment amount based on the overall machine outer and inner pressure ratio adjustment amount and the overall machine outer and inner pressure ratio change amount.

[0090] The second nozzle throat area calculation unit is used to subtract the adjustment amount of the second nozzle throat area from the original nozzle throat area after the engine nozzle retracts, so as to form the second nozzle throat area.

[0091] In some alternative embodiments, the nozzle throat adjustment module includes an interpolation unit for determining the nozzle throat area adjustment amount corresponding to the real-time low-pressure converted rotational speed through interpolation.

[0092] This application improves the thrust of the engine under throttling conditions, reduces fuel consumption, and increases the aircraft's flight range and combat radius.

[0093] Although this application has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A method for adjusting the nozzle under throttling conditions in a turbofan engine, characterized in that, include: Step S1: Obtain the first low-pressure converted speed setpoint when the engine nozzle closes, and the second low-pressure converted speed setpoint corresponding to the engine intermediate state. Step S2: Discretize multiple low-pressure converted speed control quantities within the speed range formed by the first low-pressure converted speed setpoint and the second low-pressure converted speed setpoint; Step S3: For each low-pressure converted speed control quantity, determine the first nozzle throat area when the fan stability margin is minimized under the selected low-pressure converted speed control quantity, and determine the second nozzle throat area when the inner and outer pressure ratio is 1 under the selected low-pressure converted speed control quantity. Step S4: Select the larger value between the first nozzle throat area and the second nozzle throat area as the nozzle throat area adjustment amount under the selected low-pressure converted speed control amount, and form each nozzle throat area adjustment amount corresponding to each low-pressure converted speed control amount. Step S5: When the engine enters the throttling state, adjust the nozzle throat area according to the real-time low-pressure converted speed and the correspondence between the low-pressure converted speed control amount and the nozzle throat area adjustment amount.

2. The method for adjusting the nozzle under throttling conditions of a turbofan engine as described in claim 1, characterized in that, In step S2, the speed range is discretized using a 5% speed range as the step size.

3. The method for adjusting the nozzle under throttling conditions of a turbofan engine as described in claim 1, characterized in that, In step S3, determining the throat area of ​​the first nozzle includes: Step S31: Under the selected low-pressure converted speed control condition, determine the fan surge margin adjustment amount based on the difference between the fan stability margin corresponding to the nozzle throat area after the original engine nozzle is closed and the minimum stability margin for stable fan operation. Step S32: Under the selected low-pressure converted speed control conditions, when the nozzle throat area of ​​the original engine changes by 1% after the nozzle is closed, determine the change in fan surge margin. Step S33: Determine the adjustment amount of the first nozzle throat area based on the fan surge margin adjustment amount and the fan surge margin change amount; Step S34: Subtract the adjustment amount of the first nozzle throat area from the original nozzle throat area of ​​the engine to form the first nozzle throat area.

4. The method for adjusting the nozzle under throttling conditions of a turbofan engine as described in claim 1, characterized in that, In step S3, determining the throat area of ​​the second nozzle includes: Step T31: Under the selected low-pressure converted speed control condition, determine the overall engine external internal pressure ratio adjustment amount based on the external internal pressure ratio corresponding to the nozzle throat area after the original engine nozzle is closed. Step T32: Under the selected low-pressure converted speed control conditions, when the nozzle throat area of ​​the original engine changes by 1% after the nozzle is closed, determine the change in the overall internal and external pressure ratio of the engine. Step T33: Determine the second nozzle throat area adjustment amount based on the overall machine outer and inner pressure ratio adjustment amount and the overall machine outer and inner pressure ratio change amount; Step T34: Subtract the adjustment amount of the second nozzle throat area from the original nozzle throat area of ​​the engine to form the second nozzle throat area.

5. The method for adjusting the nozzle under throttling conditions of a turbofan engine as described in claim 1, characterized in that, In step S5, the nozzle throat area adjustment amount corresponding to the real-time low-pressure converted speed is determined by interpolation.

6. A nozzle adjustment device for throttling state of a turbofan engine, characterized in that, include: The design parameter acquisition module is used to acquire the first low-pressure converted speed setpoint when the engine closes the nozzle, and the second low-pressure converted speed setpoint corresponding to the intermediate state of the engine. The low-pressure converted speed discretization module is used to discretize multiple low-pressure converted speed control quantities within the speed range formed by the first low-pressure converted speed setpoint and the second low-pressure converted speed setpoint. The nozzle throat area calculation module is used to determine the first nozzle throat area when the fan stability margin is minimized under the selected low-pressure converted speed control value for each low-pressure converted speed control value, and to determine the second nozzle throat area when the inner and outer pressure ratio is 1 under the selected low-pressure converted speed control value. The nozzle throat area selection module is used to select the larger value between the first nozzle throat area and the second nozzle throat area as the nozzle throat area adjustment amount under the selected low-pressure converted speed control amount, thereby forming each nozzle throat area adjustment amount corresponding to each low-pressure converted speed control amount. The nozzle throat adjustment module is used to adjust the nozzle throat area according to the correspondence between the low-pressure converted speed control amount and the nozzle throat area adjustment amount when the engine enters the throttling state, based on the real-time low-pressure converted speed.

7. The turbofan engine throttling state nozzle adjustment device as described in claim 6, characterized in that, In the low-pressure converted speed discretization module, the speed range is discretized using a 5% speed range as the step size.

8. The turbofan engine throttling state nozzle adjustment device as described in claim 6, characterized in that, The nozzle throat area calculation module includes: The fan surge margin adjustment unit is used to determine the fan surge margin adjustment amount based on the difference between the fan stability margin corresponding to the nozzle throat area after the original engine nozzle is closed and the minimum stability margin for stable fan operation, under the selected low-pressure converted speed control conditions. The fan surge margin change determination unit is used to determine the fan surge margin change when the nozzle throat area changes by 1% after the original engine nozzle retraction under the selected low-pressure converted speed control conditions. The first nozzle throat area adjustment calculation unit is used to determine the first nozzle throat area adjustment amount based on the fan surge margin adjustment amount and the fan surge margin change amount. The first nozzle throat area calculation unit is used to subtract the adjustment amount of the first nozzle throat area from the original nozzle throat area after the engine nozzle retracts, so as to form the first nozzle throat area.

9. The turbofan engine throttling state nozzle adjustment device as described in claim 6, characterized in that, The nozzle throat area calculation module includes: The unit for determining the overall engine's external and internal pressure ratio adjustment is used to determine the overall engine's external and internal pressure ratio adjustment amount based on the external and internal pressure ratio corresponding to the original engine's nozzle throat area after nozzle retraction, under the selected low-pressure converted speed control conditions. The unit for determining the change in the overall internal and external pressure ratio is used to determine the change in the overall internal and external pressure ratio when the area of ​​the nozzle throat after the original engine closes the nozzle changes by 1% under the selected low-pressure converted speed control conditions. The second nozzle throat area adjustment calculation unit is used to determine the second nozzle throat area adjustment amount based on the overall machine outer and inner pressure ratio adjustment amount and the overall machine outer and inner pressure ratio change amount. The second nozzle throat area calculation unit is used to subtract the adjustment amount of the second nozzle throat area from the original nozzle throat area after the engine nozzle retracts, so as to form the second nozzle throat area.

10. The turbofan engine throttling state nozzle adjustment device as described in claim 6, characterized in that, The nozzle throat adjustment module includes an interpolation unit, which is used to determine the nozzle throat area adjustment amount corresponding to the real-time low-pressure converted speed by interpolation.

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