Aeroengine exhaust system throat area adjustment device and method

Abstract

This invention provides a throat area adjustment device and method for an aero-engine exhaust system. The device is installed at the outlet of the exhaust system and includes: an adjustment module and a fairing. The fairing is located outside the adjustment module to reduce the flow resistance of the external atmosphere to the adjustment module. The adjustment module includes a rudder blade, a thrust bearing, a transmission structure, a gear, and a motor. The motor is fixed to the fairing and connected to the gear. The gear is connected to the transmission structure. The transmission structure and the rudder blade are fastened together as a rotating component. The stationary ring of the thrust bearing is fixed to the lug, and the moving ring of the thrust bearing is connected to the transmission structure and can rotate with the transmission structure. This invention can effectively reduce the weight of the exhaust system adjustment mechanism, improve the sensitivity of dynamic adjustment of the exhaust system throat area, reduce thrust loss, and enable the aero-engine to have thrust vectoring capabilities.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine structural technology and relates to a device and method for adjusting the throat area of ​​an aero-engine exhaust system. Background Technology

[0002] Dynamic adjustment of the throat area of ​​the exhaust system is a common design in power plants. It is achieved by adjusting the throat area to ensure that the aero engine maintains high efficiency under different operating conditions (such as takeoff, cruise, and acceleration).

[0003] Existing exhaust system adjustment structures are generally three-dimensional adjustable nozzles, which consist of movable adjusting vanes and sealing plates stacked together to form the internal flow channel of the exhaust system. The actuation system changes the opening of the adjusting vanes / sealing plates through an adjustment mechanism, thereby adjusting the throat area. However, this exhaust system is relatively heavy and the adjustment method is complex. Alternatively, a round-to-square transition section can be installed at the front of the exhaust system, in which case the exhaust system has a two-dimensional rectangular structure. The throat area can be adjusted by adjusting the opening of the exhaust system flow channel through an actuation system, but this exhaust system inevitably loses some thrust, reducing the efficiency of the aero-engine. Summary of the Invention

[0004] This invention provides a device and method for adjusting the throat area of ​​an aero-engine exhaust system, enabling dynamic adjustment of the throat area as the aero-engine's operating conditions change, thereby maintaining stable thrust output across a wide flight envelope. It solves the problems of heavy exhaust system weight and complex adjustment methods resulting from three-dimensional adjustable nozzle structures, and significant thrust loss caused by two-dimensional rectangular structures. This invention effectively reduces the weight of the exhaust system adjustment mechanism, improves the sensitivity of dynamic throat area adjustment, reduces thrust loss, and simultaneously enables the aero-engine to possess thrust vectoring capabilities.

[0005] The technical solution is as follows: In a first aspect, an air engine exhaust system throat area adjustment device is provided, which is installed at the outlet of the exhaust system. The device includes: an adjustment module and a fairing 2. The fairing 2 is installed outside the adjustment module to reduce the flow resistance of the external atmosphere to the adjustment module. The adjustment module includes: a rudder blade 3, a thrust bearing 4, a transmission structure 5, a gear 6, and a motor 7. The motor 7 is fixedly connected to the fairing 2. The motor 7 is connected to the gear 6. The gear 6 is connected to the transmission structure 5. The transmission structure 5 and the rudder blade 3 are fastened together as a rotating component. The stationary ring of the thrust bearing 4 is fixedly connected to the lug. The moving ring of the thrust bearing 4 is connected to the transmission structure 5 and can rotate together with the transmission structure 5.

[0006] According to the actual needs of the aircraft, pulse signals are sent to motor 7, which drives gear 6 to provide torque to transmission structure 5. Transmission structure 5 receives torque from gear 6 through its gears and then transmits the torque to rudder blade 3 through its keyway. In this way, motor 7 can provide driving force to adjust the angle of rudder blade 3. Rudder blade 3 is equipped with a key to receive torque from transmission structure 5.

[0007] The stationary ring of the thrust bearing 4 is tightly fitted with the lug and remains stationary, while the moving ring of the thrust bearing 4 is tightly fitted with the transmission structure 5 and can rotate together with the transmission structure 5. The thrust bearing 4 is used to achieve relative rotation between the rotating part and the stationary part (lug).

[0008] Through the above structural design, precise control of the exhaust system's rudder surface angle is achieved.

[0009] Furthermore, the device also includes a rectifier section 1, which is located between the exhaust system and the regulating module. It can be used to optimize the flow field state of the exhaust system, reduce energy loss caused by airflow disturbance, and improve the propulsion efficiency, stability and safety of the aero-engine.

[0010] Optionally, the stationary ring of the thrust bearing 4 is connected to the bearing ring of the lug.

[0011] The stationary ring of the thrust bearing 4 is tightly fitted with the bearing ring of the lug and remains stationary. The moving ring of the thrust bearing 4 is tightly fitted with the transmission structure 5 and can rotate together with the transmission structure 5. The thrust bearing 4 is used to achieve relative rotation between the rotating part and the stationary part (lug).

[0012] Optionally, the exhaust system cylinder wall is provided with an ear-type support, which has a hole for mating with the rudder blade. The rudder blade can be inserted during assembly. The structure is simple, reliable, and easy to assemble. The rudder blades have uniform geometric dimensions, which facilitates the control of aero-engine vector maneuvering and the mass production of rudder blades.

[0013] Optionally, the transmission structure 5 and the rudder blade 3 can be fastened together as one unit by a hexagonal nut.

[0014] In a second aspect, a method for adjusting the throat area of ​​an aircraft engine exhaust system is provided, for use in any of the devices described in the first aspect, the method comprising: Step 1: Determine the throat area based on the aerodynamic parameters of the exhaust system inlet; Step 2: Determine the required rudder blade angle based on the throat area; Step 3: Determine the parameters of the pulse signal applied to the motor based on the required rudder blade angle; Step 4: The motor receives the pulse signal and drives the gear 6. The torque of the motor is transmitted to the rudder blade through the transmission structure 5, thereby enabling the rudder blade to reach the required angle.

[0015] In step 1, the aerodynamic parameters of the exhaust system inlet include the exhaust system inlet area, total pressure of the inlet airflow, Mach number of the inlet airflow, specific heat ratio of the inlet airflow, and gas constant. The exhaust system inlet airflow flow rate is obtained based on the exhaust system inlet aerodynamic parameters. Then, the exhaust system outlet parameters of the one-dimensional flow of the exhaust system are obtained according to the exhaust system pressure ratio, including the aerodynamic and geometric parameters of the exhaust system outlet. The area of ​​the rudder blade multiplied by the sine of the angle is the area of ​​the rudder blade facing the incoming flow. The area of ​​the exhaust system throat is the geometric area of ​​the exhaust system outlet minus this area.

[0016] Specifically, based on the required rudder blade angle determined in step 2, and combined with the motor model, the motor drive angle and the duration of the pulse signal required to drive the motor are obtained.

[0017] The beneficial effects of this invention are at least as follows: The intake airflow of an aero-engine varies under different operating conditions, and the throat area controls the flow through the exhaust system. When the airflow decreases (such as during cruise), the control blade angle is increased to reduce the throat area of ​​the exhaust system, thus maintaining exhaust velocity and thrust. When the intake airflow increases (such as during acceleration), the control blade angle is decreased to increase the throat area of ​​the exhaust system, preventing airflow obstruction. This dynamic adjustment of the throat area allows the aero-engine to maintain stable thrust output across a wide flight envelope. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a conventional exhaust system. Figure 2 Schematic diagram of the throat area adjustment device for the exhaust system; Figure 3 This is a schematic diagram of the geometric position of the rudder blade when the throat area of ​​the exhaust system is at its maximum. Figure 4 This is a schematic diagram of the rudder blade's geometric position when the throat area of ​​the exhaust system is minimized. Figure 5 A schematic diagram of the transmission structure of the throat area adjustment device; Figure 6 This is an enlarged schematic diagram of the transmission structure of the adjustment device; Figure 7 This is a schematic diagram of the rudder blade's geometry.

[0020] In the diagram, 1-rectifier section, 2-fairing, 3-rudder blade, 4-thrust bearing, 5-transmission structure, 6-gear, 7-motor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0023] The structure of a conventional exhaust system is shown below. Figure 1 The airflow exits the aero-engine after passing through the constriction section. Because the geometry of this exhaust system is fixed, the throat area of ​​the exhaust system cannot be adjusted accordingly to changes in the operating conditions of the aero-engine, which is detrimental to maintaining excellent thrust performance of the aero-engine over a wide flight envelope.

[0024] Figure 2 This invention presents an exhaust system structure according to an embodiment of the present invention. Compared to the original design, this scheme includes a rectifier section 1 and a throat area adjustment device at the tail end of the exhaust system. The rectifier section 1 optimizes the flow field state of the exhaust system, reduces energy loss caused by airflow disturbance, and improves the propulsion efficiency, stability, and safety of the aero-engine. The rudder blade 3 can adjust the throat area of ​​the exhaust system according to the operating conditions of the aero-engine. Figure 3 The geometric position of rudder blade 3 is when the throat area of ​​the exhaust system is at its maximum. Figure 4This represents the geometric position of rudder blade 3 when the throat area of ​​the exhaust system is minimized. On the other hand, by changing the direction of the airflow at the exhaust system outlet, the thrust vector of the aero-engine is achieved, thereby enabling the aircraft to have three-axis control: pitch, yaw, and roll. When the horizontal rudder blade 3 swings up and down, pitch control of the aircraft can be achieved; when the vertical rudder blade 3 swings left and right, yaw control of the aircraft can be achieved; and when the rudder blade 3 rotates at the same angle, roll control of the aircraft can be achieved.

[0025] Specifically, see Figure 2 , Figure 5 and Figure 6 An embodiment of the present invention provides a throat area adjustment device for an aero-engine exhaust system, which is installed at the outlet of the exhaust system. The device includes: an adjustment module and a fairing 2. The fairing 2 is installed outside the adjustment module to reduce the flow resistance of the external atmosphere to the adjustment module. The adjustment module includes: a rudder blade 3, a thrust bearing 4, a transmission structure 5, a gear 6, and a motor 7. The motor 7 is fixed to the fairing 2. The motor 7 is connected to the gear 6. The gear 6 is connected to the transmission structure 5. The transmission structure 5 and the rudder blade 3 are fastened together as a rotating component by a hexagonal nut. The stationary ring of the thrust bearing 4 is connected to the bearing ring of the lug. The moving ring of the thrust bearing 4 is connected to the transmission structure 5 and can rotate together with the transmission structure 5.

[0026] According to the actual needs of the aircraft, pulse signals are sent to motor 7, and motor 7 drives gear 6 to provide torque to transmission structure 5; transmission structure 5, as... Figure 6 As shown, the transmission structure 5 receives torque from gear 6 via its gear, and then transmits the torque to the rudder blade 3 via its keyway. In this way, the motor 7 can provide the driving force to adjust the angle of the rudder blade 3. The geometry of the rudder blade 3 is as follows: Figure 7 As shown, it is equipped with a key to receive torque from the transmission structure 5.

[0027] The stationary ring of the thrust bearing 4 is tightly fitted with the bearing ring of the lug and remains stationary. The moving ring of the thrust bearing 4 is tightly fitted with the transmission structure 5 and can rotate together with the transmission structure 5. The thrust bearing 4 is used to achieve relative rotation between the rotating part and the stationary part (lug).

[0028] Through the above structural design, precise control of the exhaust system's rudder surface angle is achieved.

[0029] In one embodiment, the device may further include: a rectifier section 1, which is located between the exhaust system and the regulating module, for optimizing the flow field state of the exhaust system, reducing energy loss caused by airflow disturbance, and improving the propulsion efficiency, stability and safety of the aero-engine.

[0030] In one embodiment, the exhaust system casing wall is provided with an ear-type support, which has a hole for mating with the rudder blade. During assembly, the rudder blade can be inserted, resulting in a simple structure, high reliability, and low assembly difficulty. The rudder blades have uniform geometric dimensions, facilitating the control of aero-engine vector maneuvers and the mass production of rudder blades. See [link to relevant documentation]. Figure 7 .

[0031] An embodiment of the present invention also provides a method for adjusting the throat area of ​​an aero-engine exhaust system, used in the apparatus described in the embodiment of the present invention, the method comprising: Step 1: Determine the throat area based on the aerodynamic parameters of the exhaust system inlet; The inlet aerodynamic parameters of the exhaust system include the inlet area, total pressure of the inlet airflow, Mach number of the inlet airflow, specific heat ratio of the inlet airflow, and gas constant. Based on the inlet aerodynamic parameters of the exhaust system, the inlet airflow rate of the exhaust system is obtained. Then, based on the exhaust system pressure ratio, the outlet parameters of the exhaust system for one-dimensional flow are obtained, including the aerodynamic and geometric parameters of the exhaust system outlet. The area of ​​the rudder blade multiplied by the sine of the angle is the area of ​​the rudder blade facing the incoming flow. The area of ​​the exhaust system throat is the geometric area of ​​the exhaust system outlet minus this area.

[0032] Step 2: Determine the required rudder blade angle based on the throat area; Step 3: Determine the parameters of the pulse signal applied to the motor based on the required rudder blade angle; Based on the required rudder angle determined in step 2, and combined with the motor model, the driving angle of the motor and the duration of the pulse signal required to drive the motor are obtained.

[0033] Step 4: The motor receives the pulse signal and drives the gear 6. The torque of the motor is transmitted to the rudder blade through the transmission structure 5, thereby enabling the rudder blade to reach the required angle.

[0034] In this embodiment of the invention, the range of change in the throat area of ​​the exhaust system caused by the throat area adjustment device is as follows: Figure 3 and Figure 4 The exhaust system throat has the largest area (see...) Figure 3 ) to minimum area (see Figure 4 The rudder blade rotates 90 degrees. Correspondingly, the exhaust system flow rate also has maximum and minimum values. In engineering practice, exhaust system flow rate control is crucial. The specific steps for controlling exhaust system flow rate using the rudder blade are as follows: Step 1: Based on the aerodynamic parameters of the exhaust system inlet, obtain the flow rate of the exhaust system at different rudder blade angles through numerical simulation.

[0035] Given the three-dimensional geometric model of the exhaust system and the aerodynamic parameters of the exhaust system inlet and outlet, CFD software is used to numerically simulate a series of exhaust system models with different rudder angles to obtain accurate flow rates.

[0036] Step 2: Obtain the mapping relationship between the rudder blade adjustment angle and the exhaust system flow rate through a neural network.

[0037] First, the dataset obtained in step 1 is scaled to the range [0,1] to improve the convergence speed and stability of the neural network. Then, the dataset is randomly divided into three parts according to a certain ratio: a training set, a validation set, and a test set. Based on this, a feedforward neural network model is constructed to learn the nonlinear relationship between the exhaust system rudder angle (as an input feature) and the exhaust system flow rate (as a prediction target).

[0038] Step 3: Determine the rudder adjustment angle required for the exhaust system to achieve the specified flow rate based on the mapping relationship obtained in Step 2.

[0039] Step 2 yielded a model relating the exhaust system rudder angle and the exhaust system flow rate. This model allows for accurate prediction of the exhaust system flow rate given the rudder angle. Inverse optimization is then performed using this model: the model parameters are fixed, the rudder angle is used as the optimization variable, and the gradient descent method is employed to minimize the error between the predicted and target flow rates, iteratively determining the optimal rudder angle based on the target flow rate. The optimized rudder angle is then sent to the actuator, i.e., motor 7, to precisely adjust the rudder angle.

[0040] The adjustment device proposed in this invention can also enable the aero-engine to have thrust vectoring capabilities. When the horizontal rudder blades remain horizontal, simultaneously tilting the upper and lower rudder blades to the right can generate a yaw moment to the left for the aero-engine. Similar to the method of building a neural network model between the exhaust system rudder blade angle and flow rate, a model between the exhaust system rudder blade angle and the yaw moment obtained by the aero-engine can also be obtained. Using this model, a specified yaw moment can also be achieved by controlling the rudder blade angle. The specific process is as described above and will not be repeated here.

[0041] Regarding the determination of the geometry of rudder blade 3: The required throat area variation range is derived from the overall performance indicators of the exhaust system. Then, the area of ​​a single rudder blade is determined in conjunction with the rudder blade layout scheme. On the basis of meeting the area requirements, aerodynamic shape design methods are used to generate an initial geometric model of the rudder blade that takes into account flow regulation efficiency, low aerodynamic drag, and low control torque.

[0042] In this embodiment of the invention, a throat area adjustment device is installed at the outlet of the exhaust system, which can dynamically adjust the throat area of ​​the exhaust system by changing the rudder blade angle. The thrust direction can be changed by altering the rudder blade angle of the adjustment device, realizing the thrust vector of the aero-engine, thereby enabling the aircraft to have three-axis control of pitch, yaw, and roll. Torque is provided by a motor, enabling rapid response and precise control of the rudder blade angle. External drag is reduced by the fairing. Compared to an exhaust system with adjustable throat area achieved by overlapping movable adjusting plates and sealing plates, the throat area adjustment device proposed in this invention has a simpler structure, higher reliability, reduced material consumption, reduced engine weight, and improved engine efficiency. Compared to a binary rectangular exhaust system with adjustable throat area, the throat area adjustment device proposed in this invention avoids significant thrust performance loss in the exhaust system. In this invention, a rectifier section is installed at the exhaust system outlet to rectify the gas flow and improve the total pressure recovery coefficient of the exhaust system. Simultaneously, the four-blade design improves control efficiency and redundancy. The rudder blades of the throat area adjustment device proposed in this invention all adopt the same geometric dimensions, which facilitates the control of aero-engine vector maneuvering and the mass production of rudder blades.

[0043] Through the embodiments of the present invention, it is possible to rectify the gas flow, adjust the throat area of ​​the exhaust system over a wide range, and adjust the airflow direction at the exhaust system outlet, thereby improving the overall thrust performance within the flight envelope of the aero-engine and the maneuver vector control of the aircraft.

[0044] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A throat area adjustment device for an aircraft engine exhaust system, characterized in that, The device, located at the outlet of the exhaust system, includes: an adjustment module and a fairing. The fairing is located outside the adjustment module to reduce the flow resistance of the external atmosphere to the adjustment module. The adjustment module includes: a rudder blade, a thrust bearing, a transmission structure, gears, and a motor. The motor is fixed to the fairing, the motor is connected to the gear, the gear is connected to the transmission structure, and the transmission structure and the rudder are fastened together as a rotating component; the stationary ring of the thrust bearing is fixed to the lug, and the moving ring of the thrust bearing is connected to the transmission structure and can rotate with the transmission structure.

2. The apparatus according to claim 1, characterized in that, The device further includes a rectifier section, which is located between the exhaust system and the regulating module.

3. The apparatus according to claim 1, characterized in that, The stationary ring of the thrust bearing is connected to the bearing ring of the lug.

4. The apparatus according to claim 1, characterized in that, The exhaust system has lug-type supports on its cylinder wall, which have holes that mate with the rudder blades. The rudder blades have the same geometric dimensions.

5. The apparatus according to claim 1, characterized in that, The transmission structure and rudder blade are fastened together as one unit by hexagonal nuts.

6. A method for adjusting the throat area of ​​an aero-engine exhaust system, characterized in that, The method, used in the apparatus of any one of claims 1 to 5, comprises: Step 1: Determine the throat area based on the aerodynamic parameters of the exhaust system inlet; Step 2: Determine the required rudder blade angle based on the throat area; Step 3: Determine the parameters of the pulse signal applied to the motor based on the required rudder blade angle; Step 4: The motor receives pulse signals to drive the gears, and the torque of the motor is transmitted to the rudder blades through the transmission structure, thereby enabling the rudder blades to reach the required angle.

7. The method according to claim 6, characterized in that, In step 1, the aerodynamic parameters of the exhaust system inlet include the exhaust system inlet area, total pressure of the inlet airflow, Mach number of the inlet airflow, specific heat ratio of the inlet airflow, and gas constant. Based on the aerodynamic parameters of the exhaust system inlet, the exhaust system inlet airflow rate is obtained. Then, based on the exhaust system pressure ratio, the exhaust system outlet parameters for one-dimensional flow are obtained, including the aerodynamic and geometric parameters of the exhaust system outlet. The area of ​​the rudder blade multiplied by the sine of the angle is the area of ​​the rudder blade facing the incoming flow. The area of ​​the exhaust system throat is the geometric area of ​​the exhaust system outlet minus this area.

8. The method according to claim 7, characterized in that, Based on the required rudder angle determined in step 2, and combined with the motor model, the driving angle of the motor and the duration of the pulse signal required to drive the motor are obtained.

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