Method for calculating reverse thrust and net thrust of aero-engine reverse thrust device in reverse thrust state

Abstract

The application belongs to the technical field of determining reverse thrust and net thrust of an aero-engine reverse thrust device in a reverse thrust state, and particularly relates to a method for calculating reverse thrust and net thrust of an aero-engine reverse thrust device in a reverse thrust state, which adopts a fluid mechanics formula, introduces an empirical parameter, and performs one-dimensional calculation to obtain the reverse thrust and net thrust of the aero-engine reverse thrust device in the reverse thrust state according to typical section parameters of the engine, so that higher calculation efficiency can be achieved on the basis of correctness, and the method has strong theoretical and generalization properties.

Description

Technical Field

[0001] This application belongs to the technical field of determining the reverse thrust and net thrust of an aero-engine thrust reverser device, specifically relating to a method for calculating the reverse thrust and net thrust of an aero-engine thrust reverser device. Background Technology

[0002] To shorten the landing roll distance of an aircraft, a thrust reverser device for the aero-engine is designed, mainly including a flow deflector and thrust reverser blades. The flow deflector is hinged in a slot in the outer wall of the outer bypass duct and has the following characteristics:

[0003] In the positive thrust state, the flow obstruction gate blocks the slot on the outer wall of the outer bypass duct, forming part of the outer wall of the outer bypass duct, allowing the airflow from the outer bypass of the aero-engine to be discharged normally, providing thrust to the aircraft.

[0004] In reverse thrust mode, the choke deflects inwards towards the outer wall of the outer bypass duct, blocking the outer bypass duct of the aircraft engine. This forces the airflow from the outer bypass duct through slots in the outer wall, exiting via the thrust reverser blades, thus providing reverse thrust to the aircraft. This reduces the aircraft's landing roll distance. Figure 1 As shown.

[0005] Accurately obtaining the reverse thrust and net thrust of an aero-engine thrust reverser is crucial for its design and improvement. Currently, numerical simulation analysis based on flow fields is commonly used to obtain these parameters. This method requires a model of the aero-engine thrust reverser, simplification of the model, mesh generation, and research and calibration of numerical methods. While this approach can obtain a detailed global flow field of the aero-engine thrust reverser in its reverse state, leading to accurate thrust and net thrust, the complexity of aero-engine thrust reversers, the three-dimensional spatial distribution of exhaust gas flow, and the implicit function of multivariable thrust generation necessitate a certain level of theoretical and practical knowledge in numerical analysis. Furthermore, the entire process is time-consuming, demands significant computer resources, and is highly dependent on specific structural models, making it difficult to meet the rapid iterative needs for design and improvement of aero-engine thrust reversers.

[0006] This application is made in view of the aforementioned technical deficiencies.

[0007] It should be noted that the above background information is only used to assist in understanding the inventive concept and technical solution of this invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0008] The purpose of this application is to provide a method for calculating the reverse thrust and net thrust of an aero-engine reverse thrust device, so as to overcome or mitigate at least one of the known technical defects.

[0009] The technical solution of this application is:

[0010] One aspect provides a method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse state, including:

[0011] Calculate the aerodynamic parameters of the thrust reverser cascade exit section:

[0012] ;

[0013] ;

[0014] ;

[0015] ;

[0016] in,

[0017] To reverse the total pressure at the blade outlet;

[0018] For reverse calculation, the total pressure recovery coefficient of the bypass channel;

[0019] The total pressure at the inlet of the culvert;

[0020] This is the ratio of environmental pressure to the total pressure at the inlet of the thrust reverser cascade passage;

[0021] Due to environmental pressures;

[0022] To inversely calculate the velocity coefficient of the cascade passage;

[0023] The coefficient for calculating the speed coefficient of the bypass duct is denoted by , and the specific heat ratio of air is denoted by .

[0024] To inversely deduce the flow function of the cascade channel;

[0025] Calculate the leakage area of ​​the thrust reverser blade clearance:

[0026] ;

[0027] in,

[0028] To calculate the leakage area of ​​the blade clearance;

[0029] To calculate the leakage coefficient of the blade clearance;

[0030] The area of ​​the culvert entrance;

[0031] Calculate the leakage area between the choke and the outer duct in the reverse state:

[0032] ;

[0033] in,

[0034] In reverse state, the leakage area between the flow control gate and the outer duct;

[0035] In reverse state, the leakage coefficient of the gap between the flow control gate and the outer bypass duct;

[0036] Calculate the aerodynamic parameters of the outer bypass duct exhaust section in the forward thrust state:

[0037] ;

[0038] ;

[0039] ;

[0040] ;

[0041] in,

[0042] In positive thrust mode, the total exhaust pressure of the bypass duct;

[0043] For the positive push state, the total pressure recovery coefficient of the bypass channel;

[0044] For the positive push state, the ratio of environmental pressure to the total pressure at the inlet of the bypass duct;

[0045] For forward propulsion, the speed coefficient of the outer bypass duct;

[0046] For the forward propulsion state, the bypass duct flow function;

[0047] Calculate the exhaust area of ​​the bypass duct in the forward thrust state:

[0048] ;

[0049] in,

[0050] For positive thrust, the exhaust area of ​​the outer bypass duct;

[0051] For the duct flow rate;

[0052] Total temperature at the inlet of the duct;

[0053] is the exhaust area calculation coefficient, is an air thermodynamic parameter, and is the flow rate calculation constant;

[0054] Calculate the exhaust area of ​​the outer bypass duct in the reverse state:

[0055] ;

[0056] in,

[0057] In reverse state, the exhaust area of ​​the outer bypass duct;

[0058] For the reverse state, the iterative coefficients for calculating the exhaust area of ​​the outer bypass duct are used to iteratively calculate the exhaust area of ​​the outer bypass duct in the reverse state.

[0059] Calculate the outflow rate of the reverse blade cascade:

[0060] ;

[0061] ;

[0062] in,

[0063] To infer the outlet flow rate of the cascade;

[0064] This represents the total flow rate of the gap leakage.

[0065] In reverse state, the leakage flow rate between the choke and the outer bypass duct;

[0066] To calculate the leakage flow rate in the blade clearance;

[0067] Calculate the exit area of ​​the reverse blade cascade:

[0068] ;

[0069] in,

[0070] To infer the exit area of ​​the cascade;

[0071] Calculate the back-dated state and the exhaust area of ​​the outer bypass duct during iteration:

[0072] ;

[0073] in,

[0074] The iteration coefficient for calculating the exhaust area of ​​the outer bypass duct in the reverse state is stopped when it is close to the exhaust area of ​​the outer bypass duct in the reverse state.

[0075] Calculate the exhaust velocity of the thrust reverser cascade:

[0076] ;

[0077] in,

[0078] To reverse the exhaust velocity of the blade cascade;

[0079] R is the ideal gas constant;

[0080] Calculate the reverse thrust in reverse state:

[0081] ;

[0082] in,

[0083] This is the reverse thrust in the reverse state;

[0084] To reverse the exhaust angle of the blade cascade;

[0085] The backward angle of the exhaust from the reverse-thrust blade cascade.

[0086] According to at least one embodiment of this application, the above-described method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse thrust state is... ;

[0087] .

[0088] According to at least one embodiment of this application, the above-described method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse thrust state is... .

[0089] According to at least one embodiment of this application, the above-described method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse thrust state is... .

[0090] According to at least one embodiment of this application, the above-described method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse thrust state is... .

[0091] According to at least one embodiment of this application, the above-described method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse thrust state is... The initial value is 1.3.

[0092] On the other hand, a method for calculating the net thrust of an aero-engine thrust reverser in reverse state is provided, including:

[0093] Using any of the above-mentioned methods for calculating the reverse thrust of an aero-engine thrust reverser device, the reverse thrust in the reverse state is calculated. ;

[0094] Calculate the aerodynamic parameters of the outlet section of the inner duct:

[0095] ;

[0096] ;

[0097] ;

[0098] in,

[0099] For the total pressure at the outlet of the internal channel;

[0100] The total pressure recovery coefficient of the internal flow channel;

[0101] The total pressure at the inlet of the internal flow channel;

[0102] It is the ratio of environmental pressure to the total pressure at the inlet of the internal channel;

[0103] The intrinsic velocity coefficient;

[0104] Here, is the calculation coefficient for the internal velocity coefficient, and is the specific heat ratio of the gas.

[0105] Calculate the exhaust velocity in the inner duct:

[0106] ;

[0107] in,

[0108] For the exhaust speed of the internal channel;

[0109] The total temperature at the entrance of the inner passage;

[0110] Calculate the intrinsic positive thrust:

[0111] ;

[0112] in,

[0113] The inherent meaning of the Tao is the driving force;

[0114] For the internal channel outlet flow;

[0115] Calculate the leakage exhaust velocity in the reverse state between the choke and the outer bypass duct:

[0116] ;

[0117] in,

[0118] In reverse thrust mode, the leakage exhaust velocity is measured by the gap between the choke and the outer bypass.

[0119] Calculate the positive thrust generated by leakage between the choke and the outer bypass in the reverse state:

[0120] ;

[0121] in,

[0122] In the reverse thrust state, the positive thrust generated by leakage between the choke gate and the outer bypass duct;

[0123] Calculate the total reverse thrust in the reverse state:

[0124] ;

[0125] Calculate the intake impulse generated by the incoming flow velocity:

[0126] ;

[0127] in,

[0128] The intake impulse generated by the incoming flow velocity;

[0129] For the sake of inner meaning and traffic;

[0130] The incoming flow velocity;

[0131] Calculate the net thrust in reverse position:

[0132] ;

[0133] This is the net thrust in the reverse thrust state.

[0134] According to at least one embodiment of this application, the above-described method for calculating the net thrust of an aero-engine thrust reverser in reverse state is as follows: .

[0135] According to at least one embodiment of this application, the above-described method for calculating the net thrust of an aero-engine thrust reverser in reverse state is as follows: . Attached Figure Description

[0136] Figure 1 This is a schematic diagram of the aero-engine thrust reverser device provided in the embodiments of this application in the thrust reverser state;

[0137] Figure 2 This is a schematic diagram of the method for calculating the reverse thrust and net thrust of the aero-engine reverse thrust device provided in the embodiments of this application.

[0138] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual size of the product. Furthermore, the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Detailed Implementation

[0139] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0140] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0141] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0142] The following is in conjunction with the appendix Figures 1 to 2 This application will be described in further detail.

[0143] When calculating the reverse thrust and net thrust of an aero-engine's thrust reverser, given aerodynamic parameters can be obtained, as follows:

[0144] S1. Calculate the aerodynamic parameters of the thrust reverser cascade exit section:

[0145] Total pressure at the outlet of the reverse thrust vane , The value range is usually 0.84 to 0.88, with 0.86 being a more common value;

[0146] Assuming the gas fully expands to ambient pressure, the ratio of ambient pressure to the total pressure at the inlet of the thrust reverser cascade passage is... ;

[0147] velocity coefficient of the reverse thrust cascade channel k=1.4;

[0148] Flow function .

[0149] S2. Calculate the gap leakage area:

[0150] The gap leakage area includes the gap area between the thrust reverser blade blocks. and the area of ​​the gap between the flow barrier and the inner wall of the outer culvert ,in:

[0151] ;

[0152] ;

[0153] and These are the area coefficients for the thrust reverser block clearance and the choke gate clearance, respectively, typically taken as 10% and 23%.

[0154] S3. Total exhaust area in reverse thrust mode:

[0155] S31. Exhaust area under positive thrust:

[0156] Positive push export pressure , The value range is usually 0.98 to 0.99, with 0.985 being a more common value;

[0157] The ratio of forward-push ambient pressure to total pressure at the duct inlet

[0158] speed coefficient ;

[0159] Flow function ;

[0160] Forward exhaust area K=0.0404;

[0161] S32. Estimate the total exhaust area under reverse thrust conditions based on the exhaust area under positive thrust conditions:

[0162] The total exhaust area under reverse thrust conditions is obtained using coefficients. , The initial value is usually 1.3, and the final value is determined by subsequent iterations.

[0163] Total flow rate of gap leakage ;

[0164] Flow rate through the thrust reverser cascade ;

[0165] thrust reverse cascade exit area ;

[0166] The total exhaust area under reverse thrust conditions can be obtained by summation. ;

[0167] By changing Numerical value, making The iteration is completed to obtain the final outlet area and flow rate of each section.

[0168] Exhaust velocity at each section of S4:

[0169] S41. Thruster cascade exit section:

[0170] thrust reverser exhaust velocity ;

[0171] S42. Leakage section of the flow-blocking gate gap:

[0172] Assuming the leakage loss from the choke gap is consistent with the reverse thrust vane loss, then the leakage rate and exhaust velocity are... ;

[0173] Leakage flow rate at the gate gap ;

[0174] S43. Thrust reverser clearance leakage:

[0175] Assuming that the airflow between the thrust reverser blades does not generate thrust, velocity calculations are not performed.

[0176] S44. Internal nozzle exit section:

[0177] Internal export total pressure , The value range is typically 0.98 to 0.995;

[0178] Assuming the gas fully expands to ambient pressure, the ratio of ambient pressure to the total pressure at the inlet of the internal channel is... ;

[0179] speed coefficient , kh=1.3;

[0180] Flow function ;

[0181] Inner nozzle outlet exhaust velocity .

[0182] S5. Calculate Thrust

[0183] Roots thrust ;

[0184] Positive thrust ;

[0185] Gap leakage generates positive thrust ;

[0186] Total thrust ;

[0187] Considering the intake impulse generated by the incoming flow velocity ;

[0188] Net thrust .

[0189] The aforementioned method for calculating the reverse thrust and net thrust of the aero-engine thrust reverser device, based on typical engine cross-sectional parameters, employs fluid dynamics formulas and introduces empirical parameters for one-dimensional calculation to obtain the reverse thrust and net thrust of the aero-engine thrust reverser device. This method achieves high computational efficiency while ensuring accuracy and possesses strong theoretical and general applicability.

[0190] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for calculating the reverse thrust of an aero-engine thrust reverser in reverse state, characterized in that, include: Calculate the aerodynamic parameters of the thrust reverser cascade exit section: ； ； ； ； in, To reverse the total pressure at the outlet of the blade cascade; For reverse calculation, the total pressure recovery coefficient of the bypass channel; This refers to the total pressure at the inlet of the culvert. This is the ratio of environmental pressure to the total pressure at the inlet of the thrust reverser cascade passage; Due to environmental pressures; To inversely calculate the velocity coefficient of the cascade passage; Calculate the coefficients for the speed coefficient of the outer bypass duct; To inversely deduce the flow function of the cascade channel; Calculate the leakage area of ​​the thrust reverser blade clearance: ； in, To calculate the leakage area of ​​the blade clearance; To calculate the leakage coefficient of the blade clearance; This refers to the area of ​​the culvert entrance. Calculate the leakage area between the choke and the outer duct in the reverse state: ； in, In reverse state, the leakage area between the flow control gate and the outer duct; In reverse state, the leakage coefficient of the gap between the flow control gate and the outer bypass duct; Calculate the aerodynamic parameters of the outer bypass duct exhaust section in the forward thrust state: ； ； ； ； in, In positive thrust mode, the total exhaust pressure of the bypass duct; For the positive push state, the total pressure recovery coefficient of the bypass channel; For the positive push state, the ratio of environmental pressure to the total pressure at the inlet of the bypass duct; For forward propulsion, the speed coefficient of the outer bypass duct; For the forward propagation state, the bypass duct flow function; Calculate the exhaust area of ​​the outer bypass duct in the forward thrust state: ； in, For positive thrust, the exhaust area of ​​the outer bypass duct; For the duct flow rate; Total temperature at the inlet of the duct; The coefficient for calculating exhaust area; Calculate the exhaust area of ​​the outer bypass duct in the reverse state: ； in, In reverse state, the exhaust area of ​​the outer bypass duct; For the reverse state, the iterative coefficients for calculating the exhaust area of ​​the outer bypass duct are used to iteratively calculate the exhaust area of ​​the outer bypass duct in the reverse state. Calculate the outflow rate of the reverse blade cascade: ； ； in, To infer the outlet flow rate of the cascade; This represents the total flow rate of the gap leakage. In reverse state, the leakage flow rate between the choke and the outer bypass duct; To calculate the leakage flow rate in the blade clearance; Calculate the exit area of ​​the reverse blade cascade: ； in, To infer the exit area of ​​the cascade; Calculate the back-dated state and the exhaust area of ​​the outer bypass duct during iteration: ； in, The iteration coefficient for calculating the exhaust area of ​​the outer bypass duct in the reverse state is stopped when it is close to the exhaust area of ​​the outer bypass duct in the reverse state. Calculate the exhaust velocity of the thrust reverser cascade: ； in, To reverse the exhaust velocity of the blade cascade; R is the ideal gas constant; Calculate the reverse thrust in reverse state: ； in, This is the reverse thrust in the reverse state; To reverse the exhaust angle of the blade cascade; The backward angle of the exhaust from the reverse-thrust blade cascade.

2. The method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse state according to claim 1, characterized in that, ； 。 3. The method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse state according to claim 1, characterized in that, 。 4. The method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse state according to claim 1, characterized in that, 。 5. The method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse state according to claim 1, characterized in that, 。 6. The method for calculating the reverse thrust of an aero-engine thrust reverser device in reverse state according to claim 1, characterized in that, The initial value is 1.

3.

7. A method for calculating the net thrust of an aero-engine thrust reverser in reverse state, characterized in that, include: The reverse thrust in the reverse state is calculated using the reverse thrust calculation method of the aero-engine reverse thrust device according to any one of claims 1-6. ; Calculate the aerodynamic parameters of the outlet section of the inner duct: ； ； ； in, For the total pressure at the outlet of the internal channel; The total pressure recovery coefficient of the internal flow channel; The total pressure at the inlet of the internal flow channel; It is the ratio of environmental pressure to the total pressure at the inlet of the internal channel; The intrinsic velocity coefficient; Calculation coefficients for the intrinsic velocity coefficient; Calculate the exhaust velocity in the inner duct: ； in, For the exhaust speed of the internal channel; The total temperature at the entrance of the inner passage; Calculate the intrinsic positive thrust: ； in, The inherent meaning of the Tao is the driving force; For the internal channel outlet flow; Calculate the leakage exhaust velocity in the reverse state between the choke and the outer bypass duct: ； in, In reverse thrust mode, the leakage exhaust velocity is measured by the gap between the choke and the outer bypass. Calculate the positive thrust generated by leakage between the choke gate and the outer bypass in the reverse state: ； in, In the reverse thrust state, the positive thrust generated by leakage between the choke and the outer bypass duct; Calculate the total reverse thrust in the reverse state: ； Calculate the intake impulse generated by the incoming flow velocity: ； in, The intake impulse generated by the incoming flow velocity; For the sake of inner meaning and traffic; The incoming flow velocity; Calculate the net thrust in reverse position: ； This is the net thrust in the reverse thrust state.

8. The method for calculating the net thrust of an aero-engine thrust reverser in reverse state according to claim 7, characterized in that, 。 9. The method for calculating the net thrust of an aero-engine thrust reverser in thrust reverse state according to claim 7, characterized in that, 。

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