A control algorithm for accelerating an aircraft engine according to the rate of increase in engine speed

Abstract

This application belongs to the field of aero-engines, and specifically relates to a control algorithm for aero-engines accelerating according to the rate of increase of engine speed. The algorithm includes: calculating the planned value of the high-pressure rotor speed change rate control based on the speed change rate control law and the current relative equivalent speed of the high-pressure rotor; calculating the maximum deviation of the high-pressure rotor speed change rate based on the speed change rate limit law and the current relative equivalent speed of the high-pressure rotor; calculating the speed change rate deviation based on the current speed change rate and the high-pressure rotor speed change rate control plan value, and taking the smaller value between the deviation and the maximum value to obtain the change in the high-pressure rotor speed change rate; interpolating the acceleration oil correction amount from the acceleration oil correction coefficient law; obtaining the current acceleration oil-air ratio and the compressor outlet total pressure, and calculating the planned value of the fuel flow rate during the acceleration process; obtaining the fuel flow rate limit value and taking the smaller value between the fuel flow rate limit and the planned value to obtain the final fuel flow rate.

Description

Technical Field

[0001] This application belongs to the field of aero-engines, and specifically relates to a control algorithm for accelerating an aero-engine according to the rate of increase of engine speed. Background Technology

[0002] Acceleration performance is a crucial indicator for aircraft engines, directly impacting takeoff and maneuverability. However, individual engine variations and performance degradation occur during actual use, affecting acceleration performance and increasing the complexity of acceleration tuning. The engine speed rise rate control algorithm directly targets acceleration time; a well-designed algorithm can ensure satisfactory acceleration under any operating environment.

[0003] Currently, the more mature acceleration control algorithm is based on the fuel-air ratio control, i.e., W f / P3=f(n 2R ), where W f Main fuel flow rate, P3 is compressor outlet pressure, n 2R This represents the relative equivalent speed of the high-voltage rotor. Where f(n) 2R ) is a random number of n 2R The curve varies, and for some advanced engines, this curve includes an engine inlet temperature correction. A drawback of this control method is that it requires tuning based on individual engine differences and performance degradation.

[0004] In addition, in recent years, control algorithms based on the rate of increase in engine speed during acceleration have been developed. The main idea is to calculate fuel supply during acceleration according to the engine speed increase rate. Simultaneously, to ensure engine aerodynamic stability, fuel supply is subject to a high fuel-air ratio limit, which serves as the last line of defense for engine aerodynamic stability. This limit should not be reached for newly manufactured engines or engines with low usage time. However, this control algorithm can easily reach the fuel-air ratio limit when the engine control rate parameters are not set properly or when the engine is performing half-range acceleration. This not only causes the compressor operating point to fluctuate during acceleration, posing a surge risk (because fuel supply has reached the last line of defense), but also leads to excessively high main combustion chamber outlet temperatures during acceleration, indirectly accelerating engine aging.

[0005] Therefore, there is an urgent need for a technical solution to overcome or mitigate at least one of the aforementioned defects in the existing technology. Summary of the Invention

[0006] The purpose of this application is to provide a control algorithm for accelerating an aircraft engine according to the rate of increase of engine speed, in order to solve at least one problem existing in the prior art.

[0007] The technical solution of this application is:

[0008] A control algorithm for accelerating an aero-engine according to the rate of increase in engine speed includes:

[0009] Step 1: Obtain the speed change rate control law, and based on the speed change rate control law and the current high-voltage rotor relative conversion speed n... 2R Calculate the planned value n for the high-voltage rotor speed change rate control. dotdem ;

[0010] Step 2: Obtain the limit value law of the change in the speed change rate, and based on the limit value law of the change in the speed change rate and the current high-voltage rotor relative conversion speed n 2R Calculate the maximum deviation of the high-pressure rotor speed change rate dn dotmax ;

[0011] Step 3: Based on the current speed change rate n dot and the planned value n of the high-voltage rotor speed change rate control dotdem Calculate the deviation of the rotational speed change rate and compare it with the maximum deviation dn of the high-pressure rotor rotational speed change rate. dotmax Taking the smaller value yields the change in the rate of change of the high-voltage rotor speed, dn. dot =min(n dotdem -n dot dn dotmax );

[0012] Step 4: Obtain the acceleration oil correction coefficient pattern, based on the current high-pressure rotor relative conversion speed n. 2R and the change in the rate of change of high-voltage rotor speed dn dot The acceleration correction amount X is obtained by interpolation from the aforementioned acceleration correction coefficient law. Wf ;

[0013] Step 5: Obtain the current acceleration fuel-air ratio W f Based on / P3 and the compressor outlet total pressure P3, calculate the planned fuel flow rate W during acceleration. faccdem =(W f / P3)*P3*X Wf ;

[0014] Step 6: Obtain the fuel flow limit value W faccmax and the planned fuel flow value W faccdem The smaller value is used to obtain the final fuel flow rate W. facc =min(W faccdem W faccmax ).

[0015] In at least one embodiment of this application, step two, obtaining the law governing the change limit value of the rotational speed change rate, includes:

[0016] Adopting the benchmark accelerated fuel supply law (W) f / P3) jz =f(n 2R The acceleration process was calculated using the relative equivalent speeds of different high-pressure rotors as the initial speeds for acceleration.

[0017] Based on the acceleration results at different initial speeds, the relative equivalent speed n of the high-voltage rotor is plotted. 2R Curve showing the relationship between the change in the rate of change of rotational speed;

[0018] The limit value of the rate of change of rotational speed is drawn by plotting the contour on the curve of the change in quantity.

[0019] In at least one embodiment of this application, the acceleration process is calculated using 73%, 78%, 83%, 85%, 87%, and 90% of the current high-voltage rotor relative conversion speed as the initial acceleration speed.

[0020] In at least one embodiment of this application, step four, obtaining the acceleration oil correction coefficient rule, includes:

[0021] Obtain the baseline acceleration fuel injection pattern (W) f / P3) jz =f(n 2R );

[0022] The engine transient state model was used to calculate the rate of change of engine speed during acceleration under the baseline acceleration fuel supply law of 90%, 100%, 110%, 120%, and 130% respectively.

[0023] The speed change rate under the reference acceleration fuel supply rules of 90%, 110%, 120%, and 130% is compared with the speed change rate under the reference acceleration fuel supply rule of 100% to obtain the acceleration fuel correction coefficient for the change in speed change rate as the acceleration fuel-air ratio changes.

[0024] In at least one embodiment of this application, in step six, the fuel flow limit value W is obtained. faccmax ,include:

[0025] Based on the aforementioned benchmark acceleration fuel injection law, determine the acceleration fuel injection limitation law (W). f / P3) max =f(n 2R );

[0026] Based on the current relative conversion speed n of the high-pressure rotor 2R The acceleration fuel-air ratio limit value (W) is obtained by interpolation from the aforementioned acceleration fuel supply limit law. f / P3) max ;

[0027] Calculate the fuel flow limit value Wfaccmax =(W f / P3) max *P3.

[0028] In at least one embodiment of this application, the acceleration fuel supply limitation law is (W) f / P3) max =1.3*(W f / P3) jz .

[0029] The invention has at least the following beneficial technical effects:

[0030] The control algorithm for accelerating the aero-engine according to the rate of increase of engine speed in this application can ensure that the engine acceleration meets the requirements within the full envelope range and will not reduce the engine acceleration performance due to engine performance degradation; it can adapt to any acceleration process and avoid the compressor operating point being too high when the engine is in the half-acceleration stage (the starting point of acceleration is higher than the idle state). Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the speed change rate control law of one embodiment of this application;

[0032] Figure 2 This is a curve showing the relationship between the rate of change of rotational speed during the acceleration process under different initial rotational speeds in one embodiment of this application;

[0033] Figure 3 This is a schematic diagram illustrating the law governing the variation limit of the rotational speed change rate in one embodiment of this application;

[0034] Figure 4 This is a schematic diagram of the rate of change of engine speed during acceleration under different proportions of one embodiment of this application;

[0035] Figure 5 This is a schematic diagram illustrating the acceleration oil correction coefficient law of one embodiment of this application;

[0036] Figure 6 This is a schematic diagram comparing the conventional speed closed-loop acceleration simulation results of one embodiment of this application with the speed closed-loop acceleration simulation results of this scheme;

[0037] Figure 7 This is a schematic diagram comparing the compressor operating line of a conventional closed-loop acceleration process in one embodiment of this application with the compressor operating line of the closed-loop acceleration process in this solution; Detailed Implementation

[0038] 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 some, but not all, 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.

[0039] The following is in conjunction with the appendix Figures 1 to 7 This application will be described in further detail.

[0040] This application provides a control algorithm for accelerating an aircraft engine according to the rate of increase in engine speed, including the following steps:

[0041] Step 1: Obtain the speed change rate control law, and based on the speed change rate control law and the current high-voltage rotor relative conversion speed n... 2R Calculate the planned value n for the high-voltage rotor speed change rate control. dotdem ;

[0042] Step 2: Obtain the limit value of the rate of change of rotational speed, and based on the limit value of the rate of change of rotational speed and the current relative equivalent rotational speed n of the high-voltage rotor. 2R Calculate the maximum deviation of the high-pressure rotor speed change rate dn dotmax ;

[0043] Step 3: Based on the current speed change rate n dot and the planned value n of the high-voltage rotor speed change rate control dotdem Calculate the deviation of the rotational speed change rate and compare it with the maximum deviation dn of the high-pressure rotor rotational speed change rate. dotmax Taking the smaller value yields the change in the rate of change of the high-voltage rotor speed, dn. dot =min(n dotdem -n dot dn dotmax );

[0044] Step 4: Obtain the acceleration oil correction coefficient pattern, based on the current high-pressure rotor relative conversion speed n. 2R and the change in the rate of change of high-voltage rotor speed dn dot The acceleration correction amount X is obtained by interpolation from the acceleration correction coefficient law. Wf ;

[0045] Step 5: Obtain the current acceleration fuel-air ratio Wf Based on / P3 and the compressor outlet total pressure P3, calculate the planned fuel flow rate W during acceleration. faccdem =(W f / P3)*P3*X Wf ;

[0046] Step 6: Obtain the fuel flow limit value W faccmax and the planned fuel flow value W faccdem The smaller value is used to obtain the final fuel flow rate W. facc =min(W faccdem W faccmax ).

[0047] The control algorithm for accelerating an aero-engine based on the rate of increase in engine speed in this application sets acceleration process judgment conditions. When the acceleration process judgment conditions are met, acceleration fuel supply control is initiated. First, in step one, the control law of the rate of change of engine speed is obtained, such as... Figure 1 As shown, based on the speed change rate control law and the current high-voltage rotor relative equivalent speed n... 2R (%) Calculate the planned value n for the high-voltage rotor speed change rate control. dotdem (% / s).

[0048] In a preferred embodiment of this application, step two, obtaining the law governing the change limit value of the rotational speed change rate, includes:

[0049] Adopting the benchmark accelerated fuel supply law (W) f / P3) jz =f(n 2R The acceleration process was calculated using the relative equivalent speeds of different high-pressure rotors as the initial speeds for acceleration.

[0050] Based on the acceleration results at different initial speeds, the relative equivalent speed n of the high-voltage rotor is plotted. 2R The curve showing the relationship between the change in the rate of change of rotational speed and the change in rotational speed, such as Figure 2 As shown;

[0051] The limit value of the rate of change of rotational speed is plotted based on the contour of the curve of the change in quantity, such as... Figure 3 As shown.

[0052] In this embodiment, the acceleration process is calculated using 73%, 78%, 83%, 85%, 87%, and 90% of the current high-voltage rotor relative conversion speed as the initial speeds.

[0053] Then, based on the determined limit value of the rate of change of rotational speed and the current relative equivalent rotational speed n of the high-voltage rotor... 2R Calculate the maximum deviation of the high-pressure rotor speed change rate dn dotmax .

[0054] The control algorithm for accelerating an aero-engine according to the rate of increase in engine speed in this application, in step three, is based on the current rate of change of engine speed n. dot (% / s) and the planned value n of the high-pressure rotor speed change rate control dotdem Calculate the deviation of the rotational speed change rate, and compare the calculated deviation with the maximum value dn of the deviation of the high-pressure rotor rotational speed change rate. dotmax The smaller value is taken as the change in the rate of change of the high-voltage rotor speed, dn. dot =min(n dotdem -n dot dn dotmax ).

[0055] In a preferred embodiment of this application, step four, obtaining the acceleration oil correction coefficient rule, includes:

[0056] Obtain the baseline acceleration fuel injection pattern (W) f / P3) jz =f(n 2R );

[0057] The engine transient state model was used to calculate the rate of change of engine speed during acceleration under baseline acceleration fuel injection conditions of 90%, 100%, 110%, 120%, and 130%, respectively. Figure 4 As shown;

[0058] The rate of change of engine speed under the baseline acceleration fuel supply conditions of 90%, 110%, 120%, and 130% was compared with that under the baseline acceleration fuel supply condition of 100%, and the acceleration fuel correction coefficient, which measures the change in the rate of change of engine speed as a function of the acceleration fuel-air ratio, was obtained. Figure 5 As shown, the acceleration oil correction factor can characterize the sensitivity of the change in the rate of change of engine speed to the change in the acceleration oil-air ratio.

[0059] In the control algorithm for accelerating an aero-engine according to the rate of increase in engine speed, step five involves calculating the relative rotational speed n of the current high-pressure rotor. 2R The current accelerated fuel-air ratio W is obtained by interpolation from the baseline accelerated fuel supply pattern. f / P3, then obtain the current compressor outlet total pressure P3 (kPa), and calculate the planned fuel flow rate W during the acceleration process using the formula. faccdem =(W f / P3)*P3*X Wf .

[0060] The control algorithm for accelerating an aero-engine according to the rate of increase in engine speed in this application, in step six, finally obtains the fuel flow limit value W. faccmax ,include:

[0061] The acceleration fuel injection limit law (W) is determined based on the baseline acceleration fuel injection law. f / P3) max =f(n 2R );

[0062] Based on the current relative conversion speed n of the high-pressure rotor 2R The accelerated fuel-air ratio limit value (W) is obtained by interpolation from the accelerated fuel supply limit law. f / P3) max ;

[0063] Calculate the fuel flow limit value W faccmax =(W f / P3) max *P3.

[0064] The fuel flow limit value is compared with the fuel flow plan value, and the smaller value is taken as the final fuel flow. Engine acceleration control is then implemented based on the fuel flow.

[0065] In this embodiment, the accelerated fuel supply limitation law is (W f / P3) max =1.3*(W f / P3) jz .

[0066] Simulation verification, such as Figure 6 As shown, according to the simulation results of traditional closed-loop acceleration, whether it is full-range acceleration or half-range acceleration, the speed increase rate fluctuates around the control law. Moreover, the speed increase rate requirement in the initial stage of half-range acceleration is higher, resulting in greater fluctuations during the acceleration process. According to the simulation results of the closed-loop acceleration proposed in this scheme, whether it is full-range acceleration or half-range acceleration, the speed increase rate basically changes along the control law line. This is because this scheme is based on a modified open-loop acceleration fuel supply law, so the fuel supply will not fluctuate significantly. In addition, a limit on the change rate of speed is added to ensure that the speed change rate during the acceleration process changes along the control plan.

[0067] like Figure 7 As shown, comparing the compressor operating lines of the conventional and proposed closed-loop acceleration processes, the conventional closed-loop acceleration process exhibits fluctuations in the compressor operating line, corresponding to the fluctuations in the rate of change of the compressor speed during acceleration, and it also encounters the upper boundary of the compressor acceleration process. The closed-loop acceleration method proposed in this scheme exhibits no fluctuations and maintains a constant distance from the upper boundary of acceleration.

[0068] In summary, the control algorithm for accelerating aero-engines according to the rate of increase of engine speed proposed in this application adopts a closed-loop acceleration method, which makes the acceleration process smoother and retains a large compressor surge margin.

[0069] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control algorithm for accelerating an aero-engine according to the rate of increase of engine speed, characterized in that, include: Step 1: Obtain the speed change rate control law, and based on the speed change rate control law and the current high-voltage rotor relative conversion speed n... 2R Calculate the planned value n for the high-voltage rotor speed change rate control. dotdem ; Step 2: Obtain the limit value law of the change in the speed change rate, and based on the limit value law of the change in the speed change rate and the current high-voltage rotor relative conversion speed n 2R Calculate the maximum deviation of the high-pressure rotor speed change rate dn dotmax ; Step 3: Based on the current speed change rate n dot and the planned value n of the high-voltage rotor speed change rate control dotdem Calculate the deviation of the rotational speed change rate and compare it with the maximum deviation dn of the high-pressure rotor rotational speed change rate. dotmax Taking the smaller value yields the change in the rate of change of the high-voltage rotor speed, dn. dot =min(n dotdem -n dot dn dotmax ); Step 4: Obtain the acceleration oil correction coefficient pattern, based on the current high-pressure rotor relative conversion speed n. 2R and the change in the rate of change of high-voltage rotor speed dn dot The acceleration correction amount X is obtained by interpolation from the aforementioned acceleration correction coefficient law. Wf ; Step 5: Obtain the current acceleration fuel-air ratio W f Based on / P3 and the compressor outlet total pressure P3, calculate the planned fuel flow rate W during acceleration. faccdem =(W f / P3)*P3*X Wf ; Step 6: Obtain the fuel flow limit value W faccmax and the planned fuel flow value W faccdem The smaller value is used to obtain the final fuel flow rate W. facc =min(W faccdem W faccmax ).

2. The control algorithm for accelerating an aero-engine according to the rate of increase in engine speed as described in claim 1, characterized in that, In step two, the law governing the limit value of the rate of change of rotational speed is obtained, including: Adopting the benchmark accelerated fuel supply law (W) f / P3) jz =f(n 2R The acceleration process was calculated using the relative equivalent speeds of different high-pressure rotors as the initial speeds for acceleration. Based on the acceleration results at different initial speeds, the relative equivalent speed n of the high-voltage rotor is plotted. 2R Curve showing the relationship between the change in the rate of change of rotational speed; The limit value of the rate of change of rotational speed is drawn by plotting the contour on the curve of the change in quantity.

3. The control algorithm for accelerating an aero-engine according to the rate of increase in engine speed as described in claim 2, characterized in that, The acceleration process was calculated using 73%, 78%, 83%, 85%, 87%, and 90% of the current high-voltage rotor relative conversion speed as the initial acceleration speeds.

4. The control algorithm for accelerating an aero-engine according to the rate of increase in engine speed as described in claim 3, characterized in that, Step four involves obtaining the acceleration oil correction coefficient pattern, including: Obtain the baseline acceleration fuel injection pattern (W) f / P3) jz =f(n 2R ); The engine transient state model was used to calculate the rate of change of engine speed during acceleration under the baseline acceleration fuel supply law of 90%, 100%, 110%, 120%, and 130% respectively. The speed change rate under the reference acceleration fuel supply rules of 90%, 110%, 120%, and 130% is compared with the speed change rate under the reference acceleration fuel supply rule of 100% to obtain the acceleration fuel correction coefficient for the change in speed change rate as the acceleration fuel-air ratio changes.

5. The control algorithm for accelerating an aero-engine according to the rate of increase in engine speed as described in claim 4, characterized in that, In step six, obtain the fuel flow limit value W. faccmax ,include: Based on the aforementioned benchmark acceleration fuel injection law, determine the acceleration fuel injection limitation law (W). f / P3) max =f(n 2R ); Based on the current relative conversion speed n of the high-pressure rotor 2R The acceleration fuel-air ratio limit value (W) is obtained by interpolation from the aforementioned acceleration fuel supply limit law. f / P3) max ; Calculate the fuel flow limit value W faccmax =(W f / P3) max *P3.

6. The control algorithm for accelerating an aero-engine according to the rate of increase of engine speed as described in claim 5, characterized in that, The accelerated fuel supply limitation law is (W) f / P3) max =1.3*(W f / P3) jz .

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