A device for adaptively adjusting the intake flow of a pre-swirl air supply system

Abstract

The present invention relates to the technical field of pre-swirl air supply for aircraft engines, and specifically to a device for adaptively adjusting the intake flow rate of a pre-swirl air supply system, comprising: a plurality of intake guide assemblies and an intake baffle, wherein the plurality of intake guide assemblies are evenly distributed on the inner ring of a nozzle, and each intake guide assembly is connected to the leading edge of a blade of a lobe-shaped pre-swirl nozzle, an intake guide channel is formed within the intake guide assembly, and the intake guide channel is connected to the nozzle flow channel of the corresponding lobe-shaped pre-swirl nozzle; the intake baffle is rotatably arranged in the intake guide channel via a rotating shaft, and a torsion spring is provided on the rotating shaft for providing a pre-tightening force for the intake baffle. In the pre-tightening state, the intake baffle is perpendicular to the surface of the inner ring of the nozzle, and the intake baffle is driven to rotate by the differential pressure between the intake pressure under different cruise conditions and the pre-tightening force of the torsion spring to adjust the intake area of ​​the lobe-shaped pre-swirl nozzle. The present invention adjusts the amount of bleed air from the pre-swirl air supply system in real time, thereby improving engine operating efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of pre-swirl air supply for aircraft engines, and in particular to a device for adaptively regulating the intake flow of a pre-swirl air supply system. Background Art

[0002] With the advancement of modern aviation technology, the progress and development of aircraft engine technology plays a crucial role in the advancement and development of aircraft. Aircraft gas turbine engines are developing towards high efficiency with high thrust-to-weight ratios and low fuel consumption. It is generally believed that, with engine size remaining constant, every approximately 10% increase in thrust will increase turbine inlet gas temperature by 55K. Some advanced aircraft engines with thrust-to-weight ratios of 15-20 already have turbine inlet gas temperatures exceeding 2200K, and these temperatures continue to rise over time. Excessively high turbine inlet temperatures pose a challenge to safe and reliable engine operation. To address this issue, researchers are addressing two key approaches: 1) developing new high-temperature-resistant materials to increase the temperature tolerance of turbine rotor blades; and 2) employing more advanced cooling technologies to reduce the surface temperature of high-temperature components. Statistics show that the rate of increase in material temperature tolerance is far outstripping the rate of increase in turbine inlet temperature. This has led to the development of advanced and efficient cooling technologies, with the pre-swirl air supply system being one of the leading examples. The pre-swirl gas supply system has huge cooling potential. A pre-swirl gas supply system with better performance can achieve a cooling of 100K.

[0003] The cooling principle of the pre-swirl air supply system is to accelerate the airflow through the pre-swirl nozzle and generate a larger circumferential velocity component, thereby reducing the relative velocity between the static airflow and the rotor, thereby lowering the relative total airflow temperature. From a cooling perspective, the greater the amount of cooling air used, the better the effect. However, cooling air drawn from the compressor does not perform work in the turbine, which reduces engine thrust. Therefore, the amount of bleed air in the pre-swirl air supply system directly affects overall engine performance. Research has found that for every 1% increase in the amount of bleed air in the pre-swirl air supply system, engine thrust is reduced by approximately 2%. The specific fuel consumption increases by 0.7% to 0.9% at flight Mach numbers below 1.2, and by 1.2% to 1.4% at flight Mach numbers above 1.2. Using a high-bypass-ratio turbofan engine as the research object, a turbine cooling algorithm that considers cooling air usage and the associated cooling efficiency losses in the overall engine performance calculation model was introduced. The results show that a 20% reduction in cooling air usage can increase the engine's specific thrust by 3% and reduce specific fuel consumption by 0.9%. Therefore, advanced aircraft engines require more pre-swirl air supply system intake flow at high cruise conditions and less intake flow at low cruise conditions. This requires that the intake flow of the pre-swirl air supply system can be adjusted according to the cruise conditions.

[0004] In the existing technology, the currently commonly used solution for controlling the amount of bleed air in the pre-swirl air supply system is to divide the nozzle flow path into a normally open flow path and an adjustable flow path. When the engine is running under high operating conditions, all flow paths are open to ensure the amount of cooling air for the turbine blades. When the engine is running under low operating conditions, the adjustable flow path can be closed to reduce the amount of cooling air used. The traditional method is to install a valve at the last stage of the compressor, and actively adjust the bleed air valve at the last stage of the compressor according to the operating conditions of the engine to control the amount of bleed air in the pre-swirl air supply system. However, this method greatly increases the weight of the engine. The addition of an active control valve device at the last stage of the compressor not only makes assembly difficult, but also reduces the reliability of the engine operation. Therefore, a more reliable autonomous adjustment method is needed.

[0005] Therefore, it is necessary to provide a device for adaptively adjusting the intake air flow of a pre-swirl air supply system to solve the above problems. Summary of the Invention

[0006] The present invention provides a device for adaptively regulating the intake air flow of a pre-swirl air supply system. This device can autonomously adjust the intake baffle according to different engine operating conditions (such as high cruise and low cruise conditions) to adjust the bleed air volume of the pre-swirl air supply system. This ensures that the pre-swirl air supply system obtains a more appropriate bleed air volume under different operating conditions. This addresses the existing practice of installing a valve in the compressor's final stage and actively adjusting the bleed air valve there according to the engine's operating conditions to control the bleed air volume of the pre-swirl air supply system. However, this method significantly increases the weight of the engine, and the addition of an actively controlled valve device in the compressor's final stage not only increases assembly complexity but also reduces engine reliability.

[0007] The present invention provides a device for adaptively adjusting the intake air flow of a pre-swirl air supply system, which adopts the following technical solutions, including:

[0008] A plurality of air intake guide assemblies are evenly distributed on the inner ring of the nozzle, and each air intake guide assembly is connected to the leading edge of a blade of a lobe hole type pre-swirl nozzle. An air intake guide channel is formed in the air intake guide assembly, and the air intake guide channel is connected to the nozzle flow channel of the corresponding lobe hole type pre-swirl nozzle;

[0009] And the intake baffle is set in the intake guide channel by rotating the rotating shaft. A torsion spring is set on the rotating shaft to provide pre-tightening force for the intake baffle. In the pre-tightening state, the intake baffle is perpendicular to the surface of the inner ring of the nozzle. The intake baffle is driven to rotate by the difference pressure between the intake pressure of different cruising conditions and the pre-tightening force of the torsion spring to adjust the intake area entering the leaf hole type pre-swirl nozzle.

[0010] Preferably, the air intake guide assembly includes: two leading edge plates, the leading edge plates are arranged on the outer peripheral surface of the inner ring of the nozzle, the ends of the leading edge plates are connected to the leading edges of the blades of the leaf hole type pre-swirl nozzle of the inner ring of the nozzle, and an air intake guide channel is formed between the two leading edge plates.

[0011] Preferably, the end face of the air intake baffle is provided with two connecting ears, the rotating shaft is passed through the two connecting ears, the torsion spring is sleeved on the rotating shaft between the two connecting ears, and one force-bearing end of the torsion spring is in contact with the side wall of the air intake baffle, and the other force-bearing end of the torsion spring is connected to the outer peripheral surface of the inner ring of the nozzle in the air intake guide channel.

[0012] Preferably, a first groove is provided on each of the opposite surfaces in the middle of the two leading edge plates, the end of the rotating shaft is fixedly connected to the groove wall of the first groove corresponding to the leading edge plate, a second groove is provided on the outer peripheral surface of the inner ring of the nozzle between the two first grooves, and a connecting hole is provided on the second groove, wherein the force-bearing end of the torsion spring is connected to the connecting hole.

[0013] Preferably, the length of the second groove is 2 mm greater than the length of the air intake baffle, and the width of the second groove is 2 mm greater than the width of the air intake baffle.

[0014] Preferably, a plurality of through grooves are provided on the outer ring of the nozzle, and each through groove corresponds one-to-one to the second groove on the inner ring of the nozzle.

[0015] Preferably, there is an interference fit of 0.1 mm between the nozzle inner ring and the nozzle outer ring.

[0016] Preferably, both the nozzle inner ring and the nozzle outer ring are provided with pin holes for connecting the nozzle inner ring and the nozzle outer ring, and the pin holes are provided in the leading edge area of ​​the nozzle inner ring.

[0017] Preferably, the centerline direction of the air intake guide channel is parallel to the incoming flow direction.

[0018] A pre-swirl air supply system includes the device for adaptively adjusting the air intake flow of the pre-swirl air supply system according to the present invention.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention autonomously controls the corresponding intake baffle to rotate around the rotating shaft according to the intake pressure of the engine under different operating conditions and the preload force provided by the torsion spring on the intake baffle, so as to adjust the total intake area of ​​the leaf hole pre-swirl nozzle, thereby autonomously adjusting the air intake volume of the pre-swirl air supply system and improving the engine operating efficiency.

[0021] 2. Traditional methods for actively controlling bleed air flow primarily rely on the upstream compressor's final stage valve to control the flow area, resulting in lengthy adjustment times. Compared to existing technologies, the present invention adjusts the total intake area of ​​the orifice-type pre-swirl nozzle in real time based on changes in intake pressure under different engine operating conditions. This enables real-time adjustment of the bleed air flow rate of the pre-swirl air supply system under different engine operating conditions, significantly improving the system's response speed and adjustment efficiency.

[0022] 3. The present invention designs an air intake guide assembly in front of the existing vane-hole pre-swirl nozzle and sets an air intake baffle inside the air intake guide assembly to control the total area of ​​the pre-swirl nozzle. This design does not change the shape and position of the pressure and suction surfaces of the vane-hole pre-swirl nozzle, so it has almost no adverse effect on the acceleration and flow performance of the pre-swirl nozzle, thereby maintaining the efficient air entrainment capability of the pre-swirl nozzle.

[0023] The present invention is a pre-swirl nozzle device for the self-regulating function of the pre-swirl air supply system, which is simple and convenient to process and install. The nozzle leading edge extension section and the leaf hole nozzle and its nozzle inner ring are all processed as a whole. A pit is processed on the nozzle leading edge extension section to install the air intake baffle, and a blind hole is processed on the nozzle inner ring to install long screws to fix the torsion spring and the air intake baffle. Finally, the outer ring of the nozzle is processed, and a pit is also processed on the outer ring of the nozzle to install the air intake baffle. The pit of the inner ring of the nozzle corresponds to the pit of the outer ring of the nozzle one by one. During assembly, the torsion spring and the air intake baffle are first fixed in the pit by long screws, and then the outer ring of the nozzle is nested on the inner ring of the nozzle. The inner and outer rings of the nozzle are fastened together with pins. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is an enlarged view of the partial structure of a device for adaptively adjusting the intake air flow rate of a pre-swirl air supply system according to the present invention;

[0026] Figure 2 Schematic diagram of the structure of the air intake baffle, torsion spring and rotating shaft in an embodiment of the present invention;

[0027] Figure 3 This is the assembly drawing of the nozzle inner ring and the nozzle outer ring;

[0028] Figure 4 Schematic diagram of the structure of the nozzle inner ring;

[0029] Figure 5 Schematic diagram of the structure of the nozzle outer ring;

[0030] Figure 6 Schematic diagram of the through groove on the outer ring of the nozzle;

[0031] Figure 7 Schematic diagram of the intake guide channel of the intake guide assembly.

[0032] In the figure: 1. Leading edge plate; 2. Inlet baffle; 3. Torsion spring; 4. Inlet guide channel; 5. Second groove; 6. Pin hole; 7. Leaf hole type pre-swirl nozzle; 8. Rotating shaft; 9. Through groove. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] An embodiment of a device for adaptively adjusting the intake flow of a pre-swirl air supply system according to the present invention is as follows: Figure 1 As shown, it includes: an air intake baffle 2 and six air intake guide components, such as Figure 4 As shown, six air intake guide assemblies are arranged at equal intervals on the inner ring of the nozzle, and each air intake guide assembly is connected to the leading edge of the blade of a lobe hole type pre-swirl nozzle 7, and an air intake guide channel 4 is formed in the air intake guide assembly, and the air intake guide channel 4 is connected to the nozzle flow channel of the corresponding lobe hole type pre-swirl nozzle 7; an air intake baffle 2 is rotatably arranged in the air intake guide channel 4 of each air intake guide assembly through a rotating shaft 8, and a torsion spring 3 is provided on the rotating shaft 8 for providing a pre-tightening force for the air intake baffle 2. In the pre-tightening state, the air intake baffle 2 is perpendicular to the surface of the inner ring of the nozzle, and the air intake baffle 2 is driven to rotate by the differential pressure between the intake pressure of different cruising conditions and the pre-tightening force of the torsion spring 3 to adjust the air intake area entering the lobe hole type pre-swirl nozzle 7.

[0035] It should be noted that the flow channels of the lobe hole type pre-swirl nozzle 7 of this embodiment are thick solid domains, which are suitable for extending the leading edge of the pre-swirl nozzle. The lobe hole type pre-swirl nozzle 7 adopts the lobe hole type pre-swirl nozzle structure in the existing patent with application number CN20150472608.9. Then, an intake baffle 2 is provided on the basis of the lobe hole type pre-swirl nozzle 7. Because the high-temperature turbine blades require more cooling air under the high cruise condition of the engine, the pressure difference before and after the lobe hole type pre-swirl nozzle 7 increases at this time. The present invention can autonomously adjust the rotation angle of the intake baffle 2 according to the change of the pressure difference before and after the nozzle, thereby increasing the intake area of ​​the pre-swirl nozzle and preventing the insufficient supply of cooling air required by the turbine blades, thereby improving the safety and reliability of the engine.

[0036] Specifically, the air intake guide assembly includes: two leading edge plates 1, the leading edge plates 1 are arranged on the outer peripheral surface of the inner ring of the nozzle, the ends of the leading edge plates 1 are connected to the leading edges of the blades of the leaf hole type pre-swirl nozzle 7 of the inner ring of the nozzle, and an air intake guide channel 4 is formed between the two leading edge plates 1.

[0037] Specifically, the end face of the air intake baffle 2 is provided with two connecting ears, the rotating shaft 8 is passed through the two connecting ears, the torsion spring 3 is sleeved on the rotating shaft 8 between the two connecting ears, and one force-bearing end of the torsion spring 3 contacts the side wall of the air intake baffle 2, and the other force-bearing end of the torsion spring 3 is connected to the outer peripheral surface of the inner ring of the nozzle in the air intake guide channel 4.

[0038] Specifically, a first groove is provided on each of the opposite surfaces in the middle of the two leading edge plates 1, and the end of the rotating shaft 8 is fixedly connected to the groove wall of the first groove corresponding to the leading edge plate 1. A second groove 5 is provided on the outer peripheral surface of the inner ring of the nozzle between the two first grooves, and a connecting hole is provided on the second groove 5, wherein the force-bearing end of the torsion spring 3 is connected to the connecting hole.

[0039] As shown in the figure, in order to ensure that the air intake baffle 2 can rotate freely and flexibly under the pressure difference between the intake air flow and the torsion spring 3, the length of the second groove 5 in this embodiment is 2 mm larger than the length of the air intake baffle 2, and the width of the second groove 5 is 2 mm larger than the width of the air intake baffle 2.

[0040] like Figure 5 and 6 As shown, a plurality of through grooves 9 are provided on the outer ring of the nozzle, and each through groove 9 corresponds one-to-one to the second groove 5 on the inner ring of the nozzle, wherein the through grooves 9 are used to avoid affecting the rotation of the intake baffle 2 when the intake baffle 2 rotates.

[0041] Specifically, the shape of the air intake guide channel 4 is determined by the shape of the air intake baffle 2 , and can be rectangular or trapezoidal, which will not be described in detail in this embodiment.

[0042] like Figure 3 As shown, there is an interference fit of 1mm between the nozzle inner ring and the nozzle outer ring. A pin hole 6 for connecting the nozzle inner ring and the nozzle outer ring is provided on both the nozzle inner ring and the nozzle outer ring. The pin hole is provided in the leading edge area of ​​the nozzle inner ring. The pin hole of the nozzle inner ring and the nozzle outer ring are connected by a pin. Figure 4 and Figure 5 As shown, in this embodiment, the nozzle inner and outer rings are machined separately. Several lobe-shaped pre-swirl nozzles 7 are evenly distributed on the outer circumference of the inner ring. The lobe height of these lobe-shaped pre-swirl nozzles 7 is equal to the radial height of the leading edge plate 1. Furthermore, several pin holes are evenly distributed on both the inner and outer rings. To avoid significant interference with airflow, the pin holes are located on the inner ring on the leading edge of the lobe-shaped pre-swirl nozzles 7. During assembly, the torsion spring 3 and the air intake baffle 2 are first installed. The air intake baffle 2 is secured to the first groove 5 of the nozzle inner ring using the rotating shaft 8. The inner and outer rings are then connected, ensuring an interference fit of 0.1 mm in diameter. Assembly is performed by heating the outer ring.

[0043] A pre-swirl air supply system includes the device for adaptively adjusting the air intake flow of the pre-swirl air supply system according to the present invention.

[0044] How it works

[0045] like Figures 1 to 3 As shown, when the engine is in high cruise condition, the intake pressure generated by the higher flow rate and pressure of the incoming flow is greater than the preload force of the torsion spring 3 of the intake baffle 2. At this time, the intake baffle 2 is driven to rotate around the rotating shaft 8 under the pressure difference between the intake pressure and the preload force, until the intake baffle 2 gradually rotates around the rotating shaft 8 independently until it is close to the second groove 5. At this time, the intake area of ​​the leaf hole type pre-swirl nozzle 7 is increased, the intake baffle 2 is in full open mode, and the air intake volume of the pre-swirl air supply system is also increased accordingly, thereby meeting the demand for cooling air volume of the high-temperature turbine blades, that is, all the airflow in this flow path in high cruise condition enters the pre-swirl air supply system; when the engine is in low cruise condition, the rotation speed of the engine rotor components is low, and the amount of cooling air required by the turbine blades is also low. At this time, the pressure difference before and after the leaf hole type pre-swirl nozzle 7 is reduced, acting on the intake baffle. 2 is less than the preload of the torsion spring 3 of the intake baffle 2. At this time, the intake baffle 2 is automatically rotated back to its original position under the pressure difference between the preload of the torsion spring 3 and the intake pressure. At this time, the intake baffle 2 is in the fully closed mode, the intake area of ​​the leaf hole pre-swirl nozzle 7 is reduced, and the air intake of the pre-swirl air supply system is reduced to an appropriate range, which not only ensures sufficient cooling air for the turbine blades, but also improves the thrust-to-weight ratio and operating efficiency of the engine and reduces the fuel consumption rate. That is, in the low cruise condition, no airflow enters the pre-swirl air supply system in this flow path; in other cruise conditions, the intake baffle 2 drives the intake baffle 2 to rotate around the rotating shaft 8 according to the pressure difference between the intake pressure and the preload to achieve the corresponding opening adjustment, that is, the partially open mode, which is manifested as part of the airflow in this flow path entering the pre-swirl air supply system. Therefore, the present invention can autonomously adjust the intake area of ​​the leaf hole pre-swirl nozzle 7 to meet the air intake demand of the pre-swirl air supply system according to different engine working conditions.

[0046] Secondly, during assembly, first fix the torsion spring 3 and the air intake baffle 2 in the second groove through the rotating shaft 8, then nest the nozzle outer ring on the nozzle inner ring, and use pins to fasten the nozzle inner ring and the nozzle outer ring.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for adaptively adjusting the intake flow of a pre-swirl air supply system, characterized in that: include: A plurality of air intake guide assemblies are evenly distributed on the inner ring of the nozzle, and each air intake guide assembly is connected to the leading edge of a blade of a lobe hole type pre-swirl nozzle (7), an air intake guide channel (4) is formed in the air intake guide assembly, and the air intake guide channel (4) is connected to the nozzle flow channel of the corresponding lobe hole type pre-swirl nozzle (7); the air intake guide assembly comprises: two leading edge plates (1), the leading edge plates (1) are arranged on the outer peripheral surface of the inner ring of the nozzle, the end of the leading edge plate (1) is connected to the leading edge of the blade of the lobe hole type pre-swirl nozzle (7) of the inner ring of the nozzle, and the air intake guide channel (4) is formed between the two leading edge plates (1); An air intake baffle (2) is rotatably arranged in the air intake guide channel (4) via a rotating shaft (8), and a torsion spring (3) is arranged on the rotating shaft (8) for providing a pre-tightening force for the air intake baffle (2). In the pre-tightening state, the air intake baffle (2) is perpendicular to the surface of the nozzle inner ring, and the air intake baffle (2) is driven to rotate by the differential pressure between the air intake pressure under different cruise conditions and the pre-tightening force of the torsion spring (3), so as to adjust the air intake area entering the leaf hole type pre-swirl nozzle (7).

2. The device for adaptively adjusting the intake air flow of a pre-swirl air supply system according to claim 1, characterized in that: The end surface of the air intake baffle (2) is provided with two connecting ears, the rotating shaft (8) is passed through the two connecting ears, the torsion spring (3) is sleeved on the rotating shaft (8) between the two connecting ears, and one force-bearing end of the torsion spring (3) contacts the side wall of the air intake baffle (2), and the other force-bearing end of the torsion spring (3) is connected to the outer peripheral surface of the nozzle inner ring in the air intake guide channel (4).

3. The device for adaptively adjusting the intake air flow of a pre-swirl air supply system according to claim 2, characterized in that: A first groove is provided on each of the opposite surfaces in the middle of the two leading edge plates (1), and the end of the rotating shaft (8) is fixedly connected to the groove wall of the first groove corresponding to the leading edge plate (1). A second groove (5) is provided on the outer peripheral surface of the nozzle inner ring between the two first grooves, and a connecting hole is provided on the second groove (5), wherein the force-bearing end of the torsion spring (3) is connected to the connecting hole.

4. The device for adaptively adjusting the intake air flow of a pre-swirl air supply system according to claim 3, characterized in that: The length of the second groove (5) is greater than the length of the air intake baffle (2), and the width of the second groove (5) is greater than the width of the air intake baffle (2) by 1 mm to 3 mm.

5. The device for adaptively adjusting the intake air flow of a pre-swirl air supply system according to claim 3, characterized in that: A plurality of through grooves (9) are provided on the outer ring of the nozzle, and each through groove (9) corresponds one-to-one to a second groove (5) on the inner ring of the nozzle.

6. The device for adaptively adjusting the intake air flow of a pre-swirl air supply system according to claim 1, characterized in that: There is interference fit between the nozzle inner ring and the nozzle outer ring.

7. The device for adaptively adjusting the intake air flow of a pre-swirl air supply system according to claim 1, characterized in that: Both the nozzle inner ring and the nozzle outer ring are provided with pin holes (6) for connecting the nozzle inner ring and the nozzle outer ring, and the pin holes (6) are provided in the leading edge area of ​​the nozzle inner ring.

8. The device for adaptively adjusting the intake air flow of a pre-swirl air supply system according to claim 1, characterized in that: The centerline direction of the air intake guide channel (4) is parallel to the incoming flow direction.

9. A pre-swirl air supply system, characterized in that: The invention comprises a device for adaptively adjusting the air intake flow of a pre-swirl air supply system as described in any one of claims 1 to 8.

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