A method and device for controlling main fuel during acceleration of an aeroengine

Abstract

The application belongs to the technical field of engine control, and particularly relates to an aero-engine acceleration process main fuel control method and device. The method comprises the following steps: S1, calculating a main fuel supply flow conversion value based on a conversion relationship between the main fuel supply flow conversion value and a high-pressure compressor inlet equivalent speed; S2, obtaining a fan inlet total temperature at a current time of an engine, and calculating a first correction value based on a set first correction function; S3, obtaining a fan inlet total pressure at the current time of the engine, and calculating a second correction value based on a set second correction function in combination with the high-pressure compressor inlet equivalent speed; and S4, correcting the main fuel supply flow conversion value by using the first correction value and the second correction value, and determining a main fuel supply flow based on the correlation relationship. The application can meet the turbofan engine full envelope acceleration performance index, and reduce the risks of compressor surge and turbine over-temperature in the acceleration process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of engine control, and particularly relates to an aero-engine acceleration process main fuel control method and device. BACKGROUND

[0002] The acceleration performance of an aero-engine is one of important indexes for measuring the performance of the engine. Short acceleration time can greatly improve the maneuverability and combat capability of an airplane, but brings great challenges to the engine itself, which may cause insufficient engine margin, surge, stall and other problems. Therefore, how to ensure that no surge occurs in the full envelope range of the engine while the acceleration time is the shortest has become a big problem.

[0003] At present, the main fuel control law design process of the engine acceleration process is as follows: based on the acceleration index given by the user side, the main fuel control law of the engine acceleration process is given according to theoretical calculation on the basis of the steady-state fuel, and then a large number of debugging tests need to be carried out to check and find the available fuel supply law, and gradually adjust the acceleration oil to meet the index requirements.

[0004] In addition, the existing main fuel control law design of the engine acceleration process considers the non-standard day through similarity principle conversion, and does not consider the change of specific heat ratio, warm-up and thermal transient of the engine in non-standard day; at the same time, the influence of high-altitude left boundary Reynolds number is not considered. When the engine is at the high-altitude left boundary, it is in the non-self-mode area, so the low Reynolds number effect is more obvious, which makes the real component characteristics of the engine change, and the real compressor surge margin decreases. At this time, the engine acceleration process is prone to surge or the acceleration time is too long. SUMMARY

[0005] In order to solve the above problems, the application provides an aero-engine acceleration process main fuel control method and device, which realizes accurate control of the main fuel according to the inlet total temperature, inlet total pressure and high-pressure conversion speed, solves the problem of easy stall in cold days caused by inaccurate non-standard day correction of the existing main fuel control law of the engine acceleration process by increasing the non-standard day correction, and solves the problem of compressor surge in the low Reynolds number acceleration process at the high-altitude left boundary by increasing the high-altitude Reynolds number correction, so as to realize the acceleration performance index of the turbofan engine full envelope while avoiding the risks of compressor surge and turbine over-temperature in the acceleration process.

[0006] The first aspect of the application provides an aero-engine acceleration process main fuel control method, which mainly includes:

[0007] Step S1: Obtain the current high-pressure compressor inlet converted speed of the engine, and calculate the main fuel supply flow conversion value based on the conversion relationship between the main fuel supply flow conversion value and the high-pressure compressor inlet converted speed. The main fuel supply flow conversion value has a set correlation relationship with the main fuel flow, the high-pressure compressor outlet total pressure and the fan inlet total temperature.

[0008] Step S2: Obtain the current total fan inlet temperature of the engine and calculate the first correction value based on the set first correction function;

[0009] Step S3: Obtain the total fan inlet pressure of the engine at the current moment, and calculate the second correction value based on the high-pressure compressor inlet speed at the current moment, and calculate the second correction value based on the set second correction function;

[0010] Step S4: Correct the main fuel supply flow conversion value with the first correction value and the second correction value, and determine the main fuel supply flow based on the correlation.

[0011] Preferably, in step S1, the conversion relationship between the main fuel supply flow rate conversion value and the high-pressure compressor inlet converted speed is preset in the control system in the form of a first discrete table. When calculating the main fuel supply flow rate conversion value, the first discrete table is interpolated based on the real-time high-pressure compressor inlet converted speed to obtain the main fuel supply flow rate conversion value.

[0012] Preferably, determining the first discrete table includes:

[0013] The first function of main fuel supply flow rate and engine speed during engine acceleration is determined based on the overall engine performance transient state calculation model.

[0014] Based on the relationship between engine speed and the converted speed at the high-pressure compressor inlet, the main fuel supply flow rate is rewritten as a second function between the main fuel supply flow rate and the converted speed at the high-pressure compressor inlet.

[0015] The second function is converted into a tabular form according to the set step size of the independent variable, forming a first discrete table for interpolating the main fuel supply flow conversion value.

[0016] Preferably, determining the first function includes:

[0017] Using the compressor's remaining surge margin, the combustion chamber's air-fuel ratio limit, and the turbine inlet total temperature limit as boundary values ​​for the acceleration process, respectively, three first functions are calculated based on the engine's overall performance transient state calculation model.

[0018] For each independent variable, select the smallest value of the dependent variable from the three functions and combine them to form the final first function.

[0019] Preferably, in step S2, the first correction function is converted into a second discrete table and preset inside the control system. When calculating the first correction value, the second discrete table is interpolated based on the real-time acquired total fan inlet temperature to obtain the first correction value.

[0020] Preferably, determining the second discrete table includes:

[0021] Calculate the main fuel supply flow conversion value for a standard day based on the engine overall performance transition state calculation model;

[0022] Select the total fan inlet temperature for multiple non-standard days and calculate the main fuel supply flow conversion value for each non-standard day.

[0023] The conversion values ​​of the main fuel supply flow rate on each non-standard day are compared with those on the standard day, and the parameters of the first correction function are calculated based on multiple ratios.

[0024] The first correction function is converted into a tabular form according to the set step size of the independent variable, forming a second discrete table for interpolation of the first correction value.

[0025] Preferably, in step S3, the second correction function is converted into a third discrete table and preset inside the control system. When calculating the second correction value, the third discrete table is interpolated based on the real-time acquired total fan inlet pressure and high-pressure compressor inlet converted speed to obtain the second correction value.

[0026] The second aspect of this application provides a main fuel control device for the acceleration process of an aircraft engine, mainly comprising:

[0027] The main fuel supply flow conversion value calculation module is used to obtain the current high-pressure compressor inlet conversion speed of the engine, and calculate the main fuel supply flow conversion value based on the conversion relationship between the main fuel supply flow conversion value and the high-pressure compressor inlet conversion speed. The main fuel supply flow conversion value has a set correlation relationship with the main fuel flow, the high-pressure compressor outlet total pressure and the fan inlet total temperature.

[0028] The first correction value calculation module is used to obtain the total fan inlet temperature of the engine at the current moment and calculate the first correction value based on the set first correction function.

[0029] The second correction value calculation module is used to obtain the total fan inlet pressure of the engine at the current moment, and calculate the second correction value based on the set second correction function, combined with the converted speed of the high-pressure compressor inlet at the current moment.

[0030] The correction module is used to correct the main fuel supply flow conversion value with the first correction value and the second correction value, and to determine the main fuel supply flow based on the correlation.

[0031] This application can meet the full envelope acceleration performance indicators of turbofan engines and reduce the risks of compressor surge and turbine overheating during acceleration. Attached Figure Description

[0032] Figure 1 This is a flowchart of a preferred embodiment of the main fuel control method for the acceleration process of an aero-engine according to this application.

[0033] Figure 2 This is the intention of the first discrete representation.

[0034] Figure 3 This is the intention for the second discrete representation.

[0035] Figure 4 This is the intention of the third discrete representation. Detailed Implementation

[0036] 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.

[0037] The first aspect of this application provides a main fuel control method for the acceleration process of an aero engine, such as... Figure 1 As shown, it mainly includes:

[0038] Step S1: Obtain the current high-pressure compressor inlet converted speed n2r of the engine, and convert it based on the main fuel supply flow rate W. fb / (P t3 *(T t2 / 288.15) 0.5 The conversion relationship between the main fuel supply flow rate W and the high-pressure compressor inlet equivalent speed n2r is used to calculate the main fuel supply flow rate conversion value W. fb / (P t3 *(T t2 / 288.15) 0.5 The main fuel supply flow conversion value W fb / (P t3 *(T t2 / 288.15)0.5 ) and main fuel flow rate W fb Total outlet pressure P of the high-pressure compressor t3 and the total temperature T at the fan inlet t2 It has a defined association relationship.

[0039] The transformation relationship in this step is W. fb / (P t3 *(T t2 / 288.15) 0.5 )=K acc *f acc (n2r).

[0040] Among them, K acc This is an adjustable parameter with a default value of 1, and it typically takes a value between 0.95 and 1.05.

[0041] Step S2: Obtain the current total fan inlet temperature T of the engine. t2 And based on the set first correction function f t_acc (T t2 )=(T t2 / 288.15) k Calculate the first correction value f t_acc (T t2 In this step, k is usually taken as 0.2.

[0042] Step S3: Obtain the current total fan inlet pressure P of the engine. t2 And combined with the current high-pressure compressor inlet converted speed n2r, the second correction value f is calculated based on the set second correction function. Re_acc (P t2 ,n2r).

[0043] Step S4: Correct the main fuel supply flow conversion value with the first correction value and the second correction value, and determine the main fuel supply flow based on the correlation.

[0044] The correction process includes: W fb / (P t3 *(T t2 / 288.15) 0.5 )=K acc *f acc (n2r)*f t_acc (T t2 )*f Re_acc (P t2 ,n2r).

[0045] In the above formula, the main fuel supply flow conversion value W is calculated first. fb / (P t3 *(T t2 / 288.15) 0.5 Then, based on the total outlet pressure P of the high-pressure compressor... t3 and the total temperature T at the fan inlet t2 The main fuel flow rate W can then be determined. fb According to the total outlet pressure P of the high-pressure compressor of the turbofan engine. t3 Total temperature T at the fan inlet t2 The high-pressure compressor inlet conversion speed n2r and the control system realize the fuel supply to the main combustion chamber during acceleration. While meeting the full envelope acceleration performance indicators of the turbofan engine, the system avoids risks such as compressor surge and turbine overheating during acceleration.

[0046] In some optional embodiments, in step S1, the conversion relationship between the main fuel supply flow rate conversion value and the high-pressure compressor inlet converted speed is preset in the control system in the form of a first discrete table. When calculating the main fuel supply flow rate conversion value, the first discrete table is interpolated according to the real-time high-pressure compressor inlet converted speed to obtain the main fuel supply flow rate conversion value.

[0047] According to the formula in step S1, the main fuel supply flow conversion value W fb / (P t3 *(T t2 / 288.15) 0.5 The conversion relationship between K and the equivalent speed n2r at the inlet of the high-pressure compressor is K. acc *f acc The conversion relationship between (n2r) and the equivalent speed n2r at the inlet of the high-pressure compressor is as follows: Figure 2 As shown, in order to reduce the computational load of the control device, the function f is... acc (n2r) is converted to tabular form, where f acc The value of (n2r) can fluctuate up and down, ranging from 0.9 to 1.1 times.

[0048] In some alternative implementations, determining the first discrete table includes: determining a first function W of the main fuel supply flow rate and engine speed n during engine acceleration based on an engine overall performance transient state calculation model. fb / (P t3 *(T t2 ) 0.5 = f(n); Based on the relationship between engine speed and the converted speed at the high-pressure compressor inlet, the main fuel supply flow rate is rewritten as a second function between the main fuel supply flow rate and the converted speed at the high-pressure compressor inlet (i.e., W in step S1). fb / (P t3 *(T t2 / 288.15) 0.5 )=K acc *f acc(n2r)); The second function is converted into a tabular form according to the set step size of the independent variable, forming a first discrete table for interpolating the main fuel supply flow conversion value.

[0049] In this embodiment, the acceleration process fuel supply law of the main combustion chamber is actually determined by the engine's overall performance transient state calculation model. This needs to be transformed into a control form that can be implemented by the control device. A common example is W... fb =f(t), W fb =f(P t3 W fb / (P t3 *(T t2 ) 0.5 ) = f(n), where t is time. The first two forms are simple but can only characterize the control law under a single flight condition. Therefore, a third form that can be used under different flight conditions within the envelope is adopted, while the total pressure P at the high-pressure compressor outlet is... t3 When participating in control, selecting the high-pressure compressor inlet converted speed n2r for control allows the control device to accurately control the main fuel flow under different conditions of the entire envelope. Therefore, the control device adopts the following control mode:

[0050] W fb / (P t3 *(T t2 / 288.15) 0.5 )=K acc *f acc (n2r).

[0051] In some optional implementations, determining the first function includes: using the compressor remaining surge margin, combustion chamber air-fuel ratio limit, and turbine inlet total temperature limit as boundary values ​​for the acceleration process, respectively, to calculate three first functions based on the engine overall performance transition state calculation model; for each independent variable, selecting the smallest value of the dependent variable among the three functions to form the final first function.

[0052] It should be noted that during acceleration, the engine's fuel flow increases, the turbine inlet temperature rises, the turbine power exceeds the compressor power, and the engine speed increases. Using a transient state calculation model of the engine's overall performance, the compressor's remaining surge margin, the combustion chamber air-fuel ratio limit, and the turbine inlet total temperature limit are taken as boundary values ​​for the acceleration process. Three sets of main combustion control laws are calculated for the acceleration process. At each moment during acceleration, the lowest value among the three sets is selected, and the fastest acceleration characteristic satisfying the constraints is directly solved, thus obtaining the engine's optimal acceleration control law.

[0053] In some optional implementations, in step S2, the first correction function is converted into a second discrete table and preset inside the control system. When calculating the first correction value, the second discrete table is interpolated based on the real-time acquired total fan inlet temperature to obtain the first correction value.

[0054] In some optional implementations, determining the second discrete table includes: calculating the main fuel supply flow conversion value for a standard day based on the engine overall performance transition state calculation model; selecting the fan inlet total temperature for multiple non-standard days and calculating the main fuel supply flow conversion value for each non-standard day; comparing the main fuel supply flow conversion value for each non-standard day with the main fuel supply flow conversion value for a standard day, and calculating the parameters of the first correction function based on multiple ratios; converting the first correction function into a tabular form according to a set step size of the independent variable to form a second discrete table for interpolation of the first correction value.

[0055] In this embodiment, considering the effects of warm-up and thermal transients, engine acceleration tests are conducted under different intake air temperatures. For example, the intake air temperature can be selected as T. t2 =[253K, 273K, 288K, 313K], yielding the non-standard daily correction module for the main combustion chamber fuel supply pattern during acceleration, i.e., the first correction function:

[0056] f t_acc (T t2 )=(T t2 / 288.15) k Based on the total fan inlet temperature calculated over several non-standard days, the main fuel supply flow rate can be converted back to k. In multiple calculations, the value of k fluctuated between 0.1 and 0.5, with a median of approximately 0.2.

[0057] To reduce the computational load on the control device, the first correction function f t_acc (T t2 Convert to tabular form, total fan inlet temperature T t2 with f t_acc (T t2 (See relationship) Figure 3 As shown.

[0058] In some optional implementations, in step S3, the second correction function is converted into a third discrete table and preset inside the control system. When calculating the second correction value, the third discrete table is interpolated based on the real-time acquired total fan inlet pressure and high-pressure compressor inlet converted speed to obtain the second correction value.

[0059] In this embodiment, the Reynolds number at the left boundary of the upper atmosphere is relatively small, falling within the non-self-model region. Therefore, the low Reynolds number effect is more pronounced, leading to reduced engine efficiency, decreased flow rate, and a lower stability boundary. Under steady-state conditions, the fuel flow rate in the main combustion chamber at the same converted speed is higher than that at ground level. If the acceleration fuel is not corrected at this time, the acceleration process at the left boundary of the upper atmosphere is easily limited by the acceleration fuel, resulting in excessively long acceleration time. Simultaneously, the Reynolds number at the left boundary of the upper atmosphere causes a decreasing trend in the actual compressor surge margin. Therefore, a Reynolds number correction module, namely the second correction function: f, is introduced. Re_acc (P t2 The unknowns in the second correction function (n2r) are calculated in a similar way to the unknowns in the first correction function (k). Both are obtained by constructing equations or systems of equations from multiple experimental or simulation values ​​and then inversely solving them. To reduce the computational load on the control device, the function f... t_acc (T t2 Convert to tabular form, total fan inlet pressure P t2 , High-pressure compressor inlet converted speed n2r and f Re_acc (P t2 See n2r) for the relationship. Figure 4 As shown.

[0060] A second aspect of this application provides a main fuel control device for the acceleration process of an aircraft engine, corresponding to the above-described method, mainly comprising:

[0061] The main fuel supply flow conversion value calculation module is used to obtain the current high-pressure compressor inlet conversion speed of the engine, and calculate the main fuel supply flow conversion value based on the conversion relationship between the main fuel supply flow conversion value and the high-pressure compressor inlet conversion speed. The main fuel supply flow conversion value has a set correlation relationship with the main fuel flow, the high-pressure compressor outlet total pressure and the fan inlet total temperature.

[0062] The first correction value calculation module is used to obtain the total fan inlet temperature of the engine at the current moment and calculate the first correction value based on the set first correction function.

[0063] The second correction value calculation module is used to obtain the total fan inlet pressure of the engine at the current moment, and calculate the second correction value based on the set second correction function, combined with the converted speed of the high-pressure compressor inlet at the current moment.

[0064] The correction module is used to correct the main fuel supply flow conversion value with the first correction value and the second correction value, and to determine the main fuel supply flow based on the correlation.

[0065] 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 main fuel control during the acceleration process of an aero-engine, characterized in that, include: Step S1: Obtain the current high-pressure compressor inlet converted speed of the engine, and calculate the main fuel supply flow conversion value based on the conversion relationship between the main fuel supply flow conversion value and the high-pressure compressor inlet converted speed. The main fuel supply flow conversion value has a set correlation relationship with the main fuel flow, the high-pressure compressor outlet total pressure and the fan inlet total temperature. Step S2: Obtain the current total fan inlet temperature of the engine and calculate the first correction value based on the set first correction function; Step S3: Obtain the total fan inlet pressure of the engine at the current moment, and calculate the second correction value based on the high-pressure compressor inlet speed at the current moment, and calculate the second correction value based on the set second correction function; Step S4: Correct the main fuel supply flow conversion value with the first correction value and the second correction value, and determine the main fuel supply flow based on the correlation.

2. The main fuel control method for the acceleration process of an aero-engine as described in claim 1, characterized in that, In step S1, the conversion relationship between the main fuel supply flow rate and the high-pressure compressor inlet converted speed is preset in the control system in the form of a first discrete table. When calculating the main fuel supply flow rate, the main fuel supply flow rate is obtained by interpolating the first discrete table based on the real-time high-pressure compressor inlet converted speed.

3. The main fuel control method for the acceleration process of an aero-engine as described in claim 2, characterized in that, Determining the first discrete table includes: The first function of main fuel supply flow rate and engine speed during engine acceleration is determined based on the overall engine performance transient state calculation model. Based on the relationship between engine speed and the converted speed at the high-pressure compressor inlet, the main fuel supply flow rate is rewritten as a second function between the main fuel supply flow rate and the converted speed at the high-pressure compressor inlet. The second function is converted into a tabular form according to the set step size of the independent variable, forming a first discrete table for interpolating the main fuel supply flow conversion value.

4. The main fuel control method for the acceleration process of an aero-engine as described in claim 3, characterized in that, Determining the first function includes: Using the compressor's remaining surge margin, the combustion chamber's air-fuel ratio limit, and the turbine inlet total temperature limit as boundary values ​​for the acceleration process, respectively, three first functions are calculated based on the engine's overall performance transient state calculation model. For each independent variable, select the smallest value of the dependent variable from the three functions and combine them to form the final first function.

5. The main fuel control method for the acceleration process of an aero-engine as described in claim 1, characterized in that, In step S2, the first correction function is converted into a second discrete table and preset inside the control system. When calculating the first correction value, the second discrete table is interpolated based on the real-time acquired total fan inlet temperature to obtain the first correction value.

6. The main fuel control method for the acceleration process of an aero-engine as described in claim 5, characterized in that, Determining the second discrete table includes: Calculate the main fuel supply flow conversion value for a standard day based on the engine overall performance transition state calculation model; Select the total fan inlet temperature for multiple non-standard days and calculate the main fuel supply flow conversion value for each non-standard day. The conversion values ​​of the main fuel supply flow rate on each non-standard day are compared with those on the standard day, and the parameters of the first correction function are calculated based on multiple ratios. The first correction function is converted into a tabular form according to the set step size of the independent variable, forming a second discrete table for interpolation of the first correction value.

7. The main fuel control method for the acceleration process of an aero-engine as described in claim 1, characterized in that, In step S3, the second correction function is converted into a third discrete table and preset inside the control system. When calculating the second correction value, the third discrete table is interpolated based on the real-time acquired total fan inlet pressure and high-pressure compressor inlet converted speed to obtain the second correction value.

8. A main fuel control device for the acceleration process of an aero-engine, characterized in that, include: The main fuel supply flow conversion value calculation module is used to obtain the current high-pressure compressor inlet conversion speed of the engine, and calculate the main fuel supply flow conversion value based on the conversion relationship between the main fuel supply flow conversion value and the high-pressure compressor inlet conversion speed. The main fuel supply flow conversion value has a set correlation relationship with the main fuel flow, the high-pressure compressor outlet total pressure and the fan inlet total temperature. The first correction value calculation module is used to obtain the total fan inlet temperature of the engine at the current moment and calculate the first correction value based on the set first correction function. The second correction value calculation module is used to obtain the total fan inlet pressure of the engine at the current moment, and calculate the second correction value based on the set second correction function, combined with the converted speed of the high-pressure compressor inlet at the current moment. The correction module is used to correct the main fuel supply flow conversion value with the first correction value and the second correction value, and to determine the main fuel supply flow based on the correlation.

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