Retractable fan configuration aero-engine and control method

Abstract

The invention belongs to the field of aircrafts, relates to an aircraft power system design technology, and provides a retractable fan configuration aero-engine and a control method, and the engine comprises a gas turbine engine, a propulsion fan, a connecting assembly, a fan cabin door and a retractable mechanism. The gas turbine engine is located in the external pressure type air inlet channel, and the propulsion fan is arranged in a storage cabin outside the external pressure type air inlet channel. One end of the connecting assembly is connected with the gas turbine engine, and the other end is connected with the propulsion fan; the fan cabin door is arranged on the outer contour of the folding and unfolding device. The retracting and releasing mechanism is arranged on the connecting assembly and used for retracting the propelling fan into the storage cabin or releasing the propelling fan from the storage cabin when the fan cabin door is opened. The independent and controllable propulsion duct system is constructed, the structural layout of an engine can be simplified, the weight is reduced, the maintenance cost is reduced, meanwhile, the pneumatic adaptability under the multi-working-condition flight condition is guaranteed, and the voyage capacity and the pneumatic efficiency of the aircraft are comprehensively enhanced.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aircraft, and relates to a design technology of an aircraft power system, and relates to a retractable fan configuration aero-engine and a control method. BACKGROUND

[0002] With the rapid development of aviation technology, the performance requirements of aircraft on the power system present a multi-dimensional and dynamic development trend. The traditional power system is designed based on the fixed thermodynamic cycle mode, and the thermodynamic parameters and geometric configuration remain static characteristics in the working process, aiming to achieve the optimal performance at the preset working point. Although this rigid design mode can achieve high performance in a specific working condition, in the complex flight environment of a wide speed range, the engine is difficult to match the optimal balance point of the load and the thermodynamic cycle in real time, resulting in that the engine cannot balance the flight power and fuel consumption, thereby seriously restricting the continuous improvement of the comprehensive performance of the aircraft.

[0003] Therefore, a new type of power system architecture capable of actively adjusting the thermodynamic cycle parameters is urgently needed to optimize the comprehensive performance in different working conditions. By adjusting the thermodynamic cycle parameters and geometric configuration in real time, the engine can switch the working mode according to the flight conditions, thereby promoting the evolution of the engine from single-point optimization to global adaptation, and ultimately providing support for the efficient operation of the aircraft. SUMMARY

[0004] In order to solve the technical problem that the engine designed by the rigid design mode is difficult to match the optimal balance point of the load and the thermodynamic cycle in real time, and cannot balance the flight power and fuel consumption, thereby restricting the comprehensive performance of the aircraft, the application discloses a retractable fan configuration aero-engine, as shown in the figure, the retractable fan configuration aero-engine comprises a gas turbine engine, a propelling fan, a connecting assembly, a fan hatch and a retracting mechanism.

[0005] The gas turbine engine is located in the external pressure inlet, and the propelling fan is arranged in the storage cabin outside the external pressure inlet.

[0006] The connecting assembly is connected to the gas turbine engine at one end and connected to the propelling fan at the other end, and the fan hatch is arranged on the outer contour of the retracting device.

[0007] The retracting mechanism is arranged on the connecting assembly, and is used to retract the propelling fan into the storage cabin or release the propelling fan from the storage cabin when the fan hatch is opened.

[0008] Further, the gas turbine engine is arranged at the rear of the external pressure inlet in the airflow direction, and the storage cabin is arranged in front of the gas turbine engine in the airflow direction.

[0009] Further, the propulsion fan is perpendicular to the engine axis after being released from the storage cabin.

[0010] Further, the end of the external pressure inlet channel is also provided with a convergent-divergent nozzle for accelerating the airflow in the external pressure inlet channel.

[0011] Further, the connecting assembly comprises a first transmission shaft, a clutch transmission and a second transmission shaft, one end of the first transmission shaft is connected with the gas turbine engine, the other end of the first transmission shaft is connected with the clutch transmission, one end of the clutch transmission is connected with the second transmission shaft, and the other end of the second transmission shaft is engaged with the propulsion fan.

[0012] Further, when the engine is in a low fuel consumption working condition, the fan cabin door is opened, the propulsion fan is released from the storage cabin by the folding and unfolding mechanism, and the clutch transmission connects the first transmission shaft with the second transmission shaft, so that the gas turbine engine drives the propulsion fan to rotate. When the engine is in a high flight power condition, the clutch transmission disconnects the first transmission shaft from the second transmission shaft, the propulsion fan stops working, and the folding and unfolding mechanism retracts the propulsion fan into the storage cabin through the opened fan cabin door, and then closes the fan cabin door.

[0013] The embodiment of the application also provides a control method of the folding and unfolding fan configuration aero-engine. S1, a plurality of aero-engine parameters are taken as inputs, flight power and fuel consumption rate are taken as outputs, and an engine performance model is established for each typical working condition point in an aero-engine envelope range. S2, a weight coefficient is assigned to each aero-engine parameter, an optimization function is established according to flight power, fuel consumption rate and all the aero-engine parameters and corresponding weight coefficients; S3, the engine performance model and the optimization function are coupled to construct an engine performance optimization model; S4, according to the design requirements of flight power and fuel consumption rate of each typical working condition point in the aero-engine envelope range, the engine performance optimization model is used to obtain an engine control adjustment corresponding to the current working condition point, and the aero-engine is controlled in real time according to the engine control adjustment.

[0014] Further, the aero-engine parameters include fuel flow, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency and propulsion fan installation angle.

[0015] Further, the aero-engine parameters, the flight power and the specific fuel consumption are all data obtained by dimensionless processing of corresponding parameters under design conditions.

[0016] Further, the expression of the optimization function is: ; Wherein, is the optimization function value, , , , , , , are the fuel flow, the nozzle throat area, the propeller fan pressure ratio, the propeller fan efficiency, the propeller fan installation angle, the flight power and the specific fuel consumption under a certain typical condition before dimensionless processing; , , , , , , are the weight coefficients of the fuel flow, the nozzle throat area, the propeller fan pressure ratio, the propeller fan efficiency, the propeller fan installation angle, the flight power and the specific fuel consumption; , , , , , , are the fuel flow, the nozzle throat area, the propeller fan pressure ratio, the propeller fan efficiency, the propeller fan installation angle, the flight power and the specific fuel consumption under design conditions.

[0017] Compared with the prior art, the above at least one technical solution adopted by the embodiment of the present application can achieve at least the following beneficial effects: the retractable fan configuration aero-engine designed by the present application aims to replace the complex regulation system of the traditional adjustable bypass ratio engine by using the retractable propeller fan structure, and to realize the intelligent retraction and release of the propeller fan inside and outside the propulsion system by using the shaft-driven fan dynamic regulation mechanism, without configuring independent air inlet / exhaust regulation valves, so as to effectively solve the technical problem of dynamic mismatch between aerodynamic load and thermal cycle parameters of the traditional fixed thermal cycle engine during wide speed domain flight. This structural innovation maintains the high efficiency of the propulsion system, does not need to add additional flow channels (additional bypass) in the air inlet duct, and only needs to release the propeller fan duct cabin itself to form an additional bypass, which significantly simplifies the complexity of the engine bypass regulation mechanism and improves the operation reliability of the power system, thereby providing a power solution for the aircraft with compact structure, convenient control and multi-condition adaptability.

[0018] Meanwhile, the control method of the folding fan configuration aero-engine can realize wide-range bypass ratio adjustment. Through the concept of equivalent bypass ratio, the propelling fan of the folding fan configuration aero-engine works together with the gas turbine engine, and can realize wide-range equivalent bypass ratio adjustment, because the propelling fan and the engine are mechanically decoupled. The wide-range bypass ratio adjustment is not limited by the size and flow path of the engine, and the design space and variable range are expanded.

[0019] In addition, the control method can simplify the bypass ratio adjustment, and compared with the conventional adjustable bypass ratio engine, the distributed power system architecture based on the folding fan configuration can adjust the air flow of the main flow path and the bypass flow path through the optimized simulation model by adjusting the working conditions of the propelling fan, so that the complex internal adjustment mechanism of the engine is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 The structural diagram of the folding fan configuration aero-engine of the present application is shown in the figure. Figure 2 The schematic diagram of the folding fan configuration aero-engine of the present application is shown in the figure. Figure 3 The schematic diagram of the folding fan configuration aero-engine of the present application is shown in the figure. Figure 4 The control flow of the folding fan configuration aero-engine of the present application is shown in the figure. 1, fan hatch; 2, propelling fan; 3, folding mechanism; 4, clutch transmission; 5, first transmission shaft; 6, external pressure inlet; 7, gas turbine engine; 8, converging-diverging nozzle; 9, storage cabin; 10, folding device external contour; 11, second transmission shaft. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below with reference to the drawings.

[0023] Following, the embodiments of the present application will be described through specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure of the present specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in the present specification based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features of the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] The application discloses a kind of fan configuration aeroengine of retraction, see Figure 1 Fan configuration aeroengine of retraction includes gas turbine engine 7, propelling fan 2, connecting assembly, fan hatch 1 and retraction mechanism 3, as shown in the figure.

[0025] Wherein, the gas turbine engine 7 is located in the outer pressure inlet 6, for generating flight power, the propelling fan 2 is arranged in the storage cabin 9 outside the outer pressure inlet 6.

[0026] One end of the connecting assembly is connected with the gas turbine engine 7, and the other end is connected with the propelling fan 2, and the fan hatch 1 is arranged on the retraction device external contour 10.

[0027] The retraction mechanism 3 is arranged on the connecting assembly, for retracting the propelling fan 2 into the storage cabin 9 or putting out the propelling fan 2 from the storage cabin 9 when the fan hatch 1 is opened.

[0028] In the present application, see Figure 2 And Figure 3 As shown in the figure, fan hatch 1 can be opened or closed according to actual demand (flight power and fuel consumption) of engine, propelling fan 2 is put into or pushed out of storage cabin 9 by retraction mechanism 3, gas turbine engine 7 is connected with propelling fan 2 through connecting assembly, propelling fan 2 is rotated at controlled speed by rotation of gas turbine engine 7 to generate additional flight power, or gas turbine engine 7 is disconnected with propelling fan 2 to stop propelling fan 2 from working.

[0029] Further, see Figure 1As shown, the gas turbine engine 7 is positioned at the rear of the external pressure intake duct 6 along the airflow direction, and the storage compartment 9 is positioned in front of the gas turbine engine 7 along the airflow direction. Furthermore, when the propulsion fan 2 is inside the storage compartment 9, its blades are parallel to the engine axis. By designing the positions of the gas turbine engine 7 and the propulsion fan 2, the structural advantages of the engine can be fully utilized, while avoiding the risk of an excessively large aircraft engine.

[0030] Further, see Figure 2 As shown, after the propulsion fan 2 is released from the storage compartment 9, the propulsion fan blades are perpendicular to the engine axis.

[0031] Further, see Figure 1 As shown, the end of the external pressure intake duct 6 is also provided with a converging nozzle 8, which is used to accelerate the airflow in the external pressure intake duct 6 to be discharged.

[0032] Furthermore, see Figure 1 As shown, the connecting assembly includes a first drive shaft 5, a clutch transmission 4, and a second drive shaft 11. One end of the first drive shaft 5 is connected to the gas turbine engine 7, and the other end is connected to the clutch transmission 4. One end of the clutch transmission 4 is connected to the second drive shaft 11, and the other end of the second drive shaft 11 is engaged with the propulsion fan 2.

[0033] Furthermore, in aero engines, low fuel consumption mode and high flight power mode refer to two different operating modes, primarily related to engine power output and fuel efficiency. Low fuel consumption mode aims to minimize fuel consumption and is typically used during long-duration cruise flight. Its operating characteristic prioritizes engine fuel efficiency, ensuring the aircraft can maintain stable flight with the lowest possible fuel consumption. In this mode, the engine's fuel consumption is low, and its power output is only sufficient to allow the aircraft to fly at the minimum speed. High flight power mode aims to provide maximum power and is typically used during takeoff or climb. Its operating characteristic prioritizes engine power, ensuring the aircraft can reach cruise altitude in a shorter time. In this mode, the engine increases power output by increasing fuel consumption. See also Figure 2 As shown, when the engine is in a low-fuel-consumption operating condition, the fan nacelle door 1 opens, and the retraction mechanism 3 releases the propulsion fan 2 from the storage compartment 9. Then, the clutch transmission 4 engages, connecting the first drive shaft 5 to the second drive shaft 11, causing the gas turbine engine 7 to drive the propulsion fan 2 to rotate. Through the cooperation of the propulsion fan 2, the equivalent bypass ratio can be increased, propulsion efficiency improved, and fuel consumption reduced.

[0034] When the engine is under high flight power, see Figure 3As shown, when the clutch transmission 4 disengages, the first drive shaft 5 is disconnected from the second drive shaft 11, the propulsion fan 2 stops working, and the retraction mechanism 3 retracts the propulsion fan 2 into the storage compartment 9 through the opened fan compartment door 1 before closing the fan compartment door 1. At this time, the engine operates in low bypass ratio mode, which can improve flight power.

[0035] This invention also provides a control method for the above-mentioned retractable fan configuration aero-engine, see [link to relevant documentation]. Figure 4 As shown, the control method includes the following steps: S1. Using multiple aero-engine parameters as inputs and flight power and fuel consumption rate as outputs, establish an engine performance model for each typical operating point within the aero-engine envelope. In this invention, typical operating points refer to the operating conditions corresponding to the design points and non-design points within the envelope. S2. Assign weight coefficients to each aero-engine parameter, and establish an optimization function based on flight power, fuel consumption rate, and all the aero-engine parameters and their corresponding weight coefficients; S3. Couple the engine performance model with the optimization function to construct an engine performance optimization model; S4. Based on the design requirements of flight power and fuel consumption rate at each typical operating point within the envelope of the aero-engine, the engine control adjustment amount corresponding to the current operating point is obtained using the engine performance optimization model. The aero-engine is then controlled in real time according to the engine control adjustment amount, including controlling and adjusting the speed of propulsion fan 2, fuel flow, etc.

[0036] When controlling and adjusting an aircraft engine, taking the adjustment of propulsion fan 2 as an example: If the current flight mode is the same as the next flight mode, this flight mode includes not only two rough states—high flight power mode and low fuel consumption—but also detailed states corresponding to various typical operating points within the engine envelope. Based on the output results, the clutch transmission 4 can be connected to the first drive shaft 5 to control the speed of propulsion fan 2. If the current flight mode is different from the next flight mode, the fan nacelle door 1 is opened first, and then the retraction / extension mechanism 3 is activated to retract or extend propulsion fan 2 according to the predicted next flight mode. For example, if the next flight mode is low fuel consumption, the fan nacelle door 1 is opened, propulsion fan 2 is extended, and then the gas turbine engine 7 is connected to propulsion fan 2 via the clutch transmission 4, causing propulsion fan 2 to start operating. If the next flight mode is high flight power mode, the clutch transmission 4 is first controlled to disconnect the gas turbine engine 7 from propulsion fan 2, then propulsion fan 2 is retracted, and finally the fan nacelle door 1 is closed. Under normal circumstances, given a fixed installation angle for the propulsion fan, the propulsion fan pressure ratio and efficiency are directly correlated with the propulsion fan speed. Therefore, in implementing the method of this invention, the propulsion fan pressure ratio and efficiency are changed by adjusting the speed of the propulsion fan 2.

[0037] Furthermore, the aero-engine parameters include fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, and propulsion fan installation angle.

[0038] Furthermore, the aircraft engine parameters, flight power, and fuel consumption rate are all data obtained by dimensionless processing of the corresponding parameters under design conditions.

[0039] Furthermore, the expression for the optimization function is: ; in, To optimize the function value, , , , , , , These are, respectively, the dimensionless fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate before processing under a certain typical operating condition; , , , , , , The weighting coefficients are for fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate, respectively. , , , , , , These are the fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate under design conditions.

[0040] Furthermore, the weighting coefficient allocation method for each aero-engine parameter in this invention is as follows: In the low-fuel-consumption mode where the aircraft's fuel consumption is lower than the preset fuel consumption value, the weighting coefficients for the gas turbine engine fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate are all not less than 3.

[0041] When the aircraft requires power greater than the preset power value in a high flight power mode, the weighting coefficients for the gas turbine engine fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate are all less than 3 under typical operating conditions.

[0042] In this invention, when the engine is in a detailed state corresponding to various typical operating conditions, based on the design requirements of each operating condition, while ensuring the weighting coefficient of flight power or fuel consumption rate, any one or more of the following can be appropriately increased: the weighting coefficient of engine fuel flow rate, the weighting coefficient of nozzle throat area, the weighting coefficient of propulsion fan pressure ratio, the weighting coefficient of propulsion fan efficiency, and the weighting coefficient of propulsion fan installation angle, so as to meet the optimal control of the input amount expended by the engine.

[0043] This invention relates to a retractable fan configuration aero-engine, designed to replace the complex adjustment system of traditional adjustable bypass ratio engines with a retractable propulsion fan structure. By employing a shaft-driven fan dynamic adjustment mechanism, the propulsion fan can be intelligently deployed and retracted both inside and outside the propulsion system, eliminating the need for independent intake / exhaust control valves. This effectively solves the technical challenge of dynamic mismatch between aerodynamic loads and thermodynamic cycle parameters in traditional fixed thermocycle engines during wide-speed-range flight. This structural innovation maintains efficient propulsion system operation without requiring additional flow channels (extra bypass ducts) in the intake duct. The extra bypass duct is formed simply by releasing the propulsion fan duct outside the nacelle, significantly simplifying the complexity of the engine bypass adjustment mechanism, improving the operational reliability of the power system, and providing aircraft with a power solution that combines structural compactness, ease of control, and adaptability to multiple operating conditions.

[0044] Meanwhile, the control method for the retractable fan configuration aero-engine of the present invention can achieve a wide range of bypass ratio adjustment capabilities. Based on the concept of equivalent bypass ratio, this retractable fan configuration, with its propulsion fan and gas turbine engine working together, can achieve a large equivalent bypass ratio adjustment range due to the mechanical decoupling of the propulsion fan and engine. Furthermore, the bypass ratio adjustment range is not limited by engine size and flow path, expanding the design space and the range of variables.

[0045] Furthermore, the control method of the present invention simplifies the bypass ratio adjustment method. Compared with traditional adjustable bypass ratio engines, the distributed power system architecture based on this retractable fan configuration can easily adjust the airflow of the main flow channel and the bypass flow channel by adjusting multiple operating conditions of the propulsion fan through the optimized simulation model, thereby avoiding complex internal adjustment mechanisms of the engine.

[0046] Obviously, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A retractable fan configuration aircraft engine, comprising a gas turbine engine (7), said gas turbine engine (7) being located within an external pressure intake (6), characterized in that, Also includes: Propulsion fan (2), said propulsion fan (2) is located in the storage compartment (9) outside the external pressure intake duct (6); A connecting assembly, one end of which is connected to the gas turbine engine (7) and the other end of which is connected to the propulsion fan (2); Fan compartment door (1), the fan compartment door (1) is provided on the outer contour (10) of the take-up and take-down device; The retraction mechanism (3) is disposed on the connecting assembly and is used to retract the propulsion fan (2) into the storage compartment (9) or release the propulsion fan (2) from the storage compartment (9) when the fan compartment door (1) is opened.

2. The retractable fan configuration aero-engine according to claim 1, characterized in that, The gas turbine engine (7) is located in the rear section of the external pressure intake (6) along the airflow direction, and the storage tank (9) is located in front of the gas turbine engine (7) along the airflow direction.

3. The retractable fan configuration aero-engine according to claim 1, characterized in that, After the propulsion fan (2) is released from the storage compartment (9), the propulsion fan blades are perpendicular to the engine axis.

4. The retractable fan configuration aero-engine according to claim 1, characterized in that, The end of the external pressure intake (6) is also provided with a converging nozzle (8), which is used to accelerate the discharge of the airflow in the external pressure intake (6).

5. The retractable fan configuration aero-engine according to any one of claims 1 to 4, characterized in that, The connecting assembly includes a first drive shaft (5), a clutch transmission (4), and a second drive shaft (11). One end of the first drive shaft (5) is connected to the gas turbine engine (7), and the other end is connected to the clutch transmission (4). One end of the clutch transmission (4) is connected to the second drive shaft (11), and the other end of the second drive shaft (11) is engaged with the propulsion fan (2).

6. The retractable fan configuration aero-engine according to claim 5, characterized in that, When the engine is in a low fuel consumption condition, the fan compartment door (1) is opened, and the retraction mechanism (3) releases the propulsion fan (2) from the storage compartment (9). Then, the clutch transmission (4) is engaged to connect the first drive shaft (5) and the second drive shaft (11), so that the gas turbine engine (7) drives the propulsion fan (2) to rotate. When the engine is in high flight power, the clutch transmission (4) disengages and disconnects the first drive shaft (5) from the second drive shaft (11), the propulsion fan (2) stops working, and the retraction mechanism (3) retracts the propulsion fan (2) into the storage compartment (9) through the opened fan compartment door (1) before closing the fan compartment door (1).

7. A control method for a retractable fan configuration aero-engine according to any one of claims 1 to 6, characterized in that, include: Using multiple aero-engine parameters as inputs and flight power and fuel consumption rate as outputs, an engine performance model is established for each typical operating point within the aero-engine envelope. Weighting coefficients are assigned to each aero-engine parameter, and an optimization function is established based on flight power, fuel consumption rate, and all the aforementioned aero-engine parameters and their corresponding weighting coefficients. The engine performance model is coupled with the optimization function to construct an engine performance optimization model; Based on the design requirements of flight power and fuel consumption rate at each typical operating point within the envelope of the aero-engine, the engine control adjustment amount corresponding to the current operating point is obtained using the engine performance optimization model, and the aero-engine is controlled in real time according to the engine control adjustment amount.

8. The control method for a retractable fan configuration aero-engine according to claim 7, characterized in that, The parameters of the aero-engine include fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, and propulsion fan installation angle.

9. The control method for a retractable fan configuration aero-engine according to claim 8, characterized in that, The aero-engine parameters, flight power, and fuel consumption rate are all data obtained by dimensionless processing of the corresponding parameters under design conditions.

10. The control method for a retractable fan configuration aero-engine according to claim 9, characterized in that, The expression for the optimization function is: ； in, To optimize the function value, , , , , , , These are, respectively, the dimensionless fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate before processing under a certain typical operating condition; , , , , , , The weighting coefficients are for fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate, respectively. , , , , , , These are the fuel flow rate, nozzle throat area, propulsion fan pressure ratio, propulsion fan efficiency, propulsion fan installation angle, flight power, and fuel consumption rate under design conditions.

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