A performance correction method for a turbofan engine in a rain environment

Abstract

The application belongs to the field of aero-engine design, and is a performance correction method for a turbofan engine in a rain environment. The engine thrust under a dry working condition state point and the engine fuel consumption rate under the dry working condition are obtained first, and the compressor inlet parameter with the fan outlet parameter as the input is calculated. The fan and compressor pressure ratio and efficiency are calculated according to the fan and compressor inlet and outlet total temperature and total pressure. The fan and compressor flow rate, pressure ratio and efficiency are calculated to obtain the one-dimensional characteristics of the fan and compressor. The performance parameters of the engine under the corresponding rain ingestion W Rain condition are obtained through an engine performance simulation model. The correction coefficient under the corresponding rain ingestion W Rain condition at the dry working condition state point is calculated by comparing the parameters under different working conditions at the same state point. The fan and compressor characteristics under different rain ingestion conditions can be corrected, the design of each component of the engine and the matching design of the whole machine can be effectively guided, and the blank in the performance correction of the turbofan engine in the rain environment is filled.

Description

Technical Field

[0001] This application belongs to the field of aero-engine design, and specifically relates to a method for performance correction of turbofan engines in rainy environments. Background Technology

[0002] Rainfall is a common phenomenon in the natural environment. When an aircraft encounters rain during taxiing or flight, rainwater or floating raindrops can directly enter the aircraft engine through the air intake. Rainwater entering the engine's compression components exacerbates airflow losses, altering the characteristics of the fan and compressor. This adversely affects the overall engine performance and consequently impacts flight safety. Currently, there is no method to correct the performance of turbofan engines in rainy environments.

[0003] Currently, when calculating the overall performance of turbofan engines, the effect of humid air (atmospheric humidity) on engine performance can be considered, but the performance correction for engines operating in rainy environments is not taken into account. In publicly available information, there are no methods for correcting the performance of turbofan engines in rainy environments.

[0004] Therefore, how to modify the performance of turbofan engines in rainy environments is a problem that needs to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a performance correction method for turbofan engines in rainy environments, in order to solve the problem that the overall performance calculation formula for turbofan engines in rainy environments in the prior art does not perform performance correction.

[0006] The technical solution of this application is: a method for performance correction of a turbofan engine in rainy conditions, comprising:

[0007] The engine performance parameters and cross-sectional aerodynamic parameters under a dry operating condition are calculated using an engine whole-machine performance simulation model. The engine performance parameters include engine thrust and engine fuel consumption rate under dry operating conditions.

[0008] Using a 3D simulation tool for the fan and compressor, a set air intake W is calculated based on engine performance parameters and cross-sectional aerodynamic parameters. Rain The inlet and outlet flow rates, total temperature and total pressure of the fan and compressor under the given conditions are calculated, and the compressor inlet parameters are further calculated with the fan outlet parameters as input parameters.

[0009] Using Post post-processing software, surface averaging is performed based on the total temperature and total pressure at the inlet and outlet of the fan and compressor to obtain the fan inlet static temperature T1 and the total inlet temperature T1. * Total inlet pressure P1 * Fan outlet static temperature T2, outlet total temperature T2 * Total outlet pressure P2 *Total compressor outlet temperature T3 * Total outlet pressure P3 * Furthermore, the pressure ratio and efficiency of the fan and compressor were calculated.

[0010] By selecting the same rainfall inflow rate and the back pressure conditions of the fan and compressor again, the flow rate, pressure ratio and efficiency of the fan and compressor are calculated to obtain the one-dimensional characteristics of the fan and compressor.

[0011] By replacing the one-dimensional characteristics of the fan and compressor in the engine performance simulation model, the engine performance at the corresponding state point is calculated, and the corresponding throughput W is obtained. Rain Engine performance parameters under certain conditions;

[0012] The engine performance parameters under dry operating conditions are compared with those under corresponding rainfall conditions to calculate the rainfall load W under dry operating conditions. Rain Correction factor under the given conditions;

[0013] By repeatedly selecting state points under different rainfall conditions corresponding to the dry operating condition state point, the correction coefficients of each performance parameter of the engine under different rainfall conditions are obtained, and further, the correction curves of each performance parameter of the engine under different rainfall conditions under the corresponding dry operating condition are obtained.

[0014] Preferably, the method for calculating the compressor inlet parameters is as follows:

[0015] The Euler-Lagrange model is used to treat raindrops as a discrete phase and air as a continuous phase. The Euler method is used to solve the governing equations for the continuous phase of air and water vapor mixing, while the Lagrange method is used to solve the governing equations for the motion, mass transfer, and heat transfer of raindrops in the discrete phase. The coupling effect of mass, momentum, and energy between the continuous and discrete phases is realized through the Navier-Stokes equations. At the same time, a turbulence model combining the near-wall function method and KW is used, and the CAB breakup model is used to simulate the breakup process of raindrops.

[0016] Preferably, the pressure ratio and efficiency of the fan and compressor are calculated as follows:

[0017] First, calculate the fan pressure ratio based on the total pressure at the fan inlet and outlet. Then, calculate the fan air specific heat capacity at constant pressure and the fan outlet specific heat ratio based on the fan inlet static temperature. Finally, calculate the fan efficiency using the following formula:

[0018] π f =P2 * / P1 *

[0019] C p1 = 287 × (3.653 - 1.337 × 10) -3 ×T1+3.294×10 -6×T1 2 -1.913×10 -9 ×T1 3 +0.2763×10 -12 ×T1 4 )

[0020] k1=C p1 / (C p1 -287)

[0021]

[0022] First, the compressor pressure ratio is calculated based on the total pressure at the fan and compressor outlets. Then, the compressor air specific heat capacity at constant pressure and the compressor outlet specific heat ratio are calculated based on the static temperature at the fan outlet. Finally, the compressor efficiency is calculated using the following formula:

[0023] π c =P3 * / P2 *

[0024] C p2 = 287 × (3.653 - 1.337 × 10) -3 ×T2+3.294×10 -6 ×T2 2 -1.913×10 -9 ×T2 3 +0.2763×10 -12 ×T2 4 )

[0025] k2=C p2 / (C p2 -287)

[0026]

[0027] Preferably, the rainfall intake condition is set to W. Rain The percentage is 0% to 5%, which enters the fan inlet circulation area A. f The rainfall inflow of the fan-shaped area is C*W R Entering the fan inlet circulation area (1-A) f The rainfall inflow of the fan-shaped region is (1-C)*W Rain A f The percentages are 20%–50%, and C is 30%–70%. Raindrops are randomly distributed in both areas of the fan inlet, with a diameter of 100μm–300μm.

[0028] This application discloses a performance correction method for a turbofan engine under rainy conditions. First, it obtains the engine thrust and fuel consumption rate under dry operating conditions, and then calculates the compressor inlet parameters with the fan outlet parameters as the input. Based on the total temperature and total pressure at the fan and compressor inlets and outlets, it calculates the pressure ratio and efficiency of the fan and compressor. Next, it calculates the flow rate, pressure ratio, and efficiency of the fan and compressor to obtain their one-dimensional characteristics. Finally, it obtains the corresponding rainwater intake W through an engine performance simulation model. Rain Engine performance parameters under certain conditions; by comparing parameters under different operating conditions at the same state point, the rainfall throughput W corresponding to the dry operating condition is calculated. Rain The correction factor can be adjusted to correct the characteristics of the fan and compressor under different rainfall loads; it effectively guides the design of various engine components and the overall engine matching design, filling the gap in the performance correction of turbofan engines in rainy environments. Attached Figure Description

[0029] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0030] Figure 1 This is a schematic diagram of the overall process of this application. Detailed Implementation

[0031] 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.

[0032] A performance correction method for a turbofan engine under rain conditions considers different rainfall inflow rates. After dimensionality reduction processing of the three-dimensional calculation results, the characteristics of the fan and compressor under different rainfall inflow rates are obtained. Then, the correction coefficients for the overall engine performance parameters under different rainfall inflow rates are calculated. The method includes the following steps:

[0033] like Figure 1 As shown, in step S100, the main performance parameters of the engine and the main aerodynamic parameters of each section are calculated under a dry working condition state point, assuming condition A, using the engine whole-machine performance simulation model. The engine performance parameters include the engine thrust and the engine fuel consumption rate under dry working conditions.

[0034] The engine performance simulation model corresponding to the turbofan engine is an existing model. The selected dry operating condition state point is one of the state points that the turbofan engine is greatly affected by when exposed to rain. In actual calculations, multiple different dry operating condition state points can be selected to obtain correction coefficients for different operating conditions.

[0035] Step S200: Using a 3D simulation tool for the fan and compressor, such as ANSYS, calculate a set air intake W based on the engine performance parameters and cross-sectional aerodynamic parameters. Rain The inlet and outlet flow rates, total temperature and total pressure of the fan and compressor under the given conditions are calculated, and the compressor inlet parameters are further calculated with the fan outlet parameters as input parameters.

[0036] Rainfall intake condition setting W Rain The percentage is 0% to 5%, which enters the fan inlet circulation area A. f The rainfall inflow of the fan-shaped area is C*W R Entering the fan inlet circulation area (1-A) f The rainfall inflow of the fan-shaped region is (1-C)*W Rain A f The percentages are 20%–50%, and C is 30%–70%. Raindrops are randomly distributed in both areas of the fan inlet, with a diameter of 100μm–300μm.

[0037] The calculation method for compressor inlet parameters is as follows:

[0038] The Euler-Lagrange model is used to treat raindrops as a discrete phase and air as a continuous phase. The Euler method is used to solve the governing equations for the continuous phase of air and water vapor mixing, while the Lagrange method is used to solve the governing equations for the motion, mass transfer, and heat transfer of raindrops in the discrete phase. The coupling effect of mass, momentum, and energy between the continuous and discrete phases is realized through the Navier-Stokes equations. At the same time, a turbulence model combining the near-wall function method and KW is used, and the CAB breakup model is used to simulate the breakup process of raindrops, thereby ensuring the accuracy of the compressor inlet parameter calculation.

[0039] By using 3D simulation tools to simulate the real environment under rain conditions, and then using algorithms to calculate the compressor inlet parameters under this environment, different rain conditions and different rainfall inflows can be obtained by changing the simulation parameters, thereby effectively improving the efficiency of obtaining compressor inlet parameters under rain conditions.

[0040] Step S300: Using the Post post-processing software built into the 3D simulation tool, surface averaging is performed based on the total temperature and total pressure at the inlet and outlet of the fan and compressor to obtain the fan inlet static temperature T1 and the total inlet temperature T2. * Total inlet pressure P1 * Fan outlet static temperature T2, outlet total temperature T2 * Total outlet pressure P2 * Total compressor outlet temperature T3 * Total outlet pressure P3 * Furthermore, the pressure ratio and efficiency of the fan and compressor were calculated.

[0041] Preferably, the calculation method for the pressure ratio and efficiency of the fan and compressor is as follows:

[0042] First, calculate the fan pressure ratio based on the total pressure at the fan inlet and outlet. Then, calculate the fan air specific heat capacity at constant pressure and the fan outlet specific heat ratio based on the fan inlet static temperature. Finally, calculate the fan efficiency using the following formula:

[0043] π f =P2 * / P1 * (1)

[0044] C p1 = 287 × (3.653 - 1.337 × 10) -3 ×T1+3.294×10 -6 ×T1 2 -1.913×10 -9 ×T1 3 +0.2763×10 -12 ×T1 4 (2)

[0045] k1=C p1 / (C p1 -287) (3)

[0046]

[0047] First, the compressor pressure ratio is calculated based on the total pressure at the fan and compressor outlets. Then, the compressor air specific heat capacity at constant pressure and the compressor outlet specific heat ratio are calculated based on the static temperature at the fan outlet. Finally, the compressor efficiency is calculated using the following formula:

[0048] π c =P3 * / P2 * (5)

[0049] C p2 = 287 × (3.653 - 1.337 × 10) -3 ×T2+3.294×10 -6 ×T2 2 -1.913×10 -9 ×T2 3 +0.2763×10 -12 ×T2 4 (6)

[0050] k2=C p2 / (C p2 -287) (7)

[0051]

[0052] Step S400: Repeat steps S200-S300. By selecting the same rainwater intake and the back pressure conditions of the fan and compressor again, calculate the flow rate, pressure ratio and efficiency (including surge point and blockage point) of the fan and compressor to obtain the one-dimensional characteristics of the fan and compressor.

[0053] By performing dimensionality reduction on the 3D calculation results, the amount of computation can be effectively reduced and the computational efficiency can be improved.

[0054] Step S500: Replace the one-dimensional characteristics of the fan and compressor in the engine performance simulation model, calculate the engine performance under condition A, and obtain the corresponding air intake W. Rain Engine performance parameters under certain conditions, such as F wet and SFC wet wait;

[0055] Step S600: Compare the engine performance parameters under condition A in step S100 with the engine performance parameters under the corresponding rainfall load condition in step S500, and calculate the rainfall load corresponding to the dry operating condition point, such as F. wet and SFC wet Correction factor under the same conditions;

[0056] Since the performance of turbofan engines differs under rainy and dry conditions, a comparison can be made to accurately determine the differences between the two and thus the correction factor.

[0057] Step S700: Repeatedly select the state points corresponding to different rainfall throughput conditions under condition A to obtain the correction coefficients of each performance parameter of the engine under different rainfall throughput conditions, and further obtain the correction curves of each performance parameter of the engine under different rainfall throughput conditions under condition A, such as f KF (W Rain ) and W Rain The relationship and f Ksfc (W Rain ) and W Rain Relationships, etc.

[0058] This application first obtains the engine thrust and fuel consumption rate under dry operating conditions, and then calculates the compressor inlet parameters with the fan outlet parameters as the input parameters. Based on the total temperature and total pressure at the inlet and outlet of the fan and compressor, the pressure ratio and efficiency of the fan and compressor are calculated. Next, the flow rate, pressure ratio, and efficiency of the fan and compressor are calculated to obtain the one-dimensional characteristics of the fan and compressor. Finally, the corresponding throughput W is obtained through an engine performance simulation model. Rain Engine performance parameters under certain conditions; by comparing parameters under different operating conditions at the same state point, the rainfall throughput W corresponding to the dry operating condition is calculated. RainThe correction factor can be adjusted to correct the characteristics of the fan and compressor under different rainfall loads; it effectively guides the design of various engine components and the overall engine matching design, filling the gap in the performance correction of turbofan engines in rainy environments.

[0059] Note: W Rain —Rainwater intake, defined as the ratio of the mass flow rate of rainwater entering the engine to the mass flow rate of air entering the engine inlet; A f —The ratio of the area of ​​the rain-swallowing fan-shaped zone at the fan inlet to the total flow area at the fan inlet; C is the rain-swallowing capacity allocation coefficient; T1—The static temperature at the fan inlet; T1 * —Total temperature at the fan inlet; P1 * —Total pressure at the fan inlet; T2—Static temperature at the fan outlet; T2 * —Total temperature at the fan outlet; P2 * —Total pressure at the fan outlet; T3 * —Compressor outlet total temperature; P3 * —Compressor outlet total pressure; C p1 —Specific heat capacity of air at constant pressure; k1—Specific heat ratio of air in the fan; C p2 —Specific heat capacity of compressor air at constant pressure; k2 —Specific heat ratio of compressor air; F Dry —Engine thrust under dry operating conditions; sfc Dry —Engine fuel consumption rate under dry operating conditions; F wet —Rainfall amount is W Rain Engine thrust under certain conditions; SFC wet —Rainfall amount is W Rain Engine fuel consumption rate under certain conditions; K F —Rainfall amount is W Rain Engine thrust correction factor, K F =F wet / F Dry ;sfc Dry —Rainfall amount is W Rain Engine fuel consumption rate correction factor, K sfc =F wet / F Dry ;f KF (W Rain — Engine thrust correction factor under rain conditions, f Ksfc (W Rain ) is the engine fuel consumption rate correction factor under rain conditions.

[0060] 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 method for performance correction of a turbofan engine under rainy conditions, characterized in that, include: The engine performance parameters and cross-sectional aerodynamic parameters under a dry operating condition are calculated using an engine whole-machine performance simulation model. The engine performance parameters include engine thrust and engine fuel consumption rate under dry operating conditions. Using a 3D simulation tool for the fan and compressor, a set air intake W is calculated based on engine performance parameters and cross-sectional aerodynamic parameters. Rain The inlet and outlet flow rates, total temperature and total pressure of the fan and compressor under the given conditions are calculated, and the compressor inlet parameters are further calculated with the fan outlet parameters as input parameters. Using Post post-processing software, surface averaging is performed based on the total temperature and total pressure at the inlet and outlet of the fan and compressor to obtain the fan inlet static temperature T1 and the total inlet temperature T1. * Total inlet pressure P1 * Fan outlet static temperature T2, outlet total temperature T2 * Total outlet pressure P2 * Total compressor outlet temperature T3 * Total outlet pressure P3 * Furthermore, the pressure ratio and efficiency of the fan and compressor were calculated. By selecting the same rainfall inflow rate and the back pressure conditions of the fan and compressor again, the flow rate, pressure ratio and efficiency of the fan and compressor are calculated to obtain the one-dimensional characteristics of the fan and compressor. By replacing the one-dimensional characteristics of the fan and compressor in the engine performance simulation model, the engine performance at the corresponding state point is calculated, and the corresponding throughput W is obtained. Rain Engine performance parameters under certain conditions; The engine performance parameters under dry operating conditions are compared with those under corresponding rainfall conditions to calculate the rainfall condition W under dry operating conditions. Rain Correction factor below; By repeatedly selecting state points under different rainfall conditions corresponding to the dry operating condition state point, the correction coefficients of each performance parameter of the engine under different rainfall conditions are obtained, and further, the correction curves of each performance parameter of the engine under different rainfall conditions under the corresponding dry operating condition are obtained.

2. The performance correction method for turbofan engines in rainy environments as described in claim 1, characterized in that, The calculation method for the compressor inlet parameters is as follows: The Euler-Lagrange model is used to treat raindrops as a discrete phase and air as a continuous phase. The Euler method is used to solve the governing equations for the continuous phase of air and water vapor mixing, while the Lagrange method is used to solve the governing equations for the motion, mass transfer, and heat transfer of raindrops in the discrete phase. The coupling effect of mass, momentum, and energy between the continuous and discrete phases is realized through the Navier-Stokes equations. At the same time, a turbulence model combining the near-wall function method and KW is used, and the CAB breakup model is used to simulate the breakup process of raindrops.

3. The performance correction method for turbofan engines under rainy conditions as described in claim 1, characterized in that, The calculation methods for the pressure ratio and efficiency of the fan and compressor are as follows: First, calculate the fan pressure ratio based on the total pressure at the fan inlet and outlet. Then, calculate the fan air specific heat capacity at constant pressure and the fan outlet specific heat ratio based on the fan inlet static temperature. Finally, calculate the fan efficiency using the following formula: p f =P2 * / P1 * C p1 =287×(3.653-1.337×10 -3 ×T1+3.294×10 -6 ×T1 2 -1.913×10 -9 ×T1 3 +0.2763×10 -12 ×T1 4 ) k1=C p1 / (C p1 -287) First, the compressor pressure ratio is calculated based on the total pressure at the fan and compressor outlets. Then, the compressor air specific heat capacity at constant pressure and the compressor outlet specific heat ratio are calculated based on the static temperature at the fan outlet. Finally, the compressor efficiency is calculated using the following formula: p c =P3 * / P2 * C p2 =287×(3.653-1.337×10 -3 ×T2+3.294×10 -6 ×T2 2 -1.913×10 -9 ×T2 3 +0.2763×10 -12 ×T2 4 ) k2=C p2 / (C p2 -287) 4. The performance correction method for turbofan engines in rainy environments as described in claim 1, characterized in that: The rainfall inflow condition is set to W. Rain The percentage is 0% to 5%, which enters the fan inlet circulation area A. f The rainfall inflow of the fan-shaped area is C*W R Entering the fan inlet circulation area (1-A) f The rainfall inflow of the fan-shaped region is (1-C)*W Rain A f The percentages are 20%–50%, and C is 30%–70%. Raindrops are randomly distributed in both areas of the fan inlet, with a diameter of 100μm–300μm.

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