CN116771561A - Axisymmetric air inlet channel and low-energy fluid control method - Google Patents
Axisymmetric air inlet channel and low-energy fluid control method Download PDFInfo
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Abstract
The invention relates to an axisymmetric air inlet channel and a low-energy fluid control method, belonging to the technical field of aircrafts; the axisymmetric air inlet comprises a hollow two-stage center cone, a diffuser connected with the hollow two-stage center cone and a lip cover arranged on the periphery of the diffuser; the two-stage center cone is axially divided into a first-stage center cone and a second-stage center cone; the first-stage central cone is a head of the central cone, and the tail end of the inner cone surface of the first-stage central cone extends out of the lap joint surface along the direction of the bus; the lap joint surface is provided with a drainage groove along the circumferential direction; the second-stage center cone is a conical sleeve, the small-diameter end of the second-stage center cone is connected with the tail end of the first-stage center cone in a sealing manner, and the large-diameter end of the second-stage center cone is connected with the diffusion section; the diffusion section is controlled by the driving assembly, can expand outwards along the radial direction, and simultaneously drives the second-stage center cone to slide along the bus direction of the joint surface, so that the on-off control of the drainage groove is completed. The invention can improve the internal flow field of the wide-speed-range air inlet channel and timely control low-energy fluid generated by the mutual interference of shock wave boundary layers in the air inlet channel.
Description
Technical Field
The invention belongs to the technical field of aircrafts, and particularly relates to an axisymmetric air inlet channel and a low-energy fluid control method.
Background
For the supersonic air inlet of large airspace and wide speed range flight, the design difficulty of the air inlet is that the performance at low altitude and low speed and the performance at high altitude and high speed are simultaneously considered. At low altitude and low speed, the total shrinkage ratio of the air inlet channel is usually required to be designed smaller, and the throat is designed larger so as to meet the requirement of large flow; in the high-altitude high-speed state, in order to fully exert the thrust performance of the engine, the compression efficiency of the air inlet is required to be improved, the required throat area is usually smaller, the contradiction is more prominent along with the widening of the working range of the air inlet, the conventional fixed-geometry air inlet generally adopts a compromise design method, the overall performance of the air inlet is reduced, and the problem that the work of the air inlet in a wide Mach number range needs to be solved is solved by how to solve the contradiction; in addition, the leakage groove is an indispensable part of the wide-speed-range air inlet channel, and the air inlet channel is not started under the action of high back pressure when the ultrasonic speed flies, and the main reason is that: the fast developed boundary layer acts on the shock wave, so that the shock wave system enters the contraction section of the air inlet channel, flow separation, flow blockage and flow capture drop are caused, the flow field of the air inlet channel is unstable, and the phenomenon that the air inlet channel is not started occurs. That is, the rapid development of the boundary layer is an important cause of the inlet passage not being started.
The method for adjusting the throat area disclosed in the prior art comprises the steps of adopting a movable central body to axially move so as to change the opening of a turbine channel; the protrusions of the memory alloy plates are adopted to change the throat height; the driving device is adopted to control the throttle cone to move along the incoming flow direction, so that the section of the throat is changed; the movable throat plate is adopted to adjust the incoming flow of the air inlet channel. These techniques only disclose methods of throat area or height adjustment, but do not allow the fast developing boundary layer to be drawn out of the intake duct, thus increasing the interaction of the boundary layer and shock waves, affecting the anti-back pressure capability of the intake duct. Therefore, how to design a device that can change the contraction ratio of the air inlet channel and meet the opening and closing problems of the drainage groove in different speed ranges under the condition of meeting the overall performance requirement of the engine is a closely focused problem of related researchers.
Disclosure of Invention
The technical problems to be solved are as follows:
in order to avoid the defects of the prior art, the invention provides an axisymmetric air inlet and a low-energy fluid control method, wherein the air inlet adopts a center cone of a split sealing structure, and can meet the throat area requirement of the air inlet in a wide speed range by combining the characteristic of controllable axial linear motion of a second-stage center cone; the flow discharging groove is coupled with the split center cone, the opening and closing of the flow discharging groove can be controlled while the throat area is regulated, so that the high flow requirement of the engine under the low incoming flow Mach number is met, and the low-energy fluid in the air inlet channel is discharged under the high incoming flow Mach number; the invention can improve the internal flow field of the wide-speed-range air inlet, timely control low-energy fluid generated by the mutual interference of shock wave boundary layers in the air inlet, improve the total pressure recovery coefficient of the air inlet, and lay a technical foundation for engineering application of the wide-speed-range air inlet and even development of an advanced aircraft.
The technical scheme of the invention is as follows: an axisymmetric air inlet comprises a hollow two-stage center cone, a diffuser connected with the hollow two-stage center cone and a lip cover arranged on the periphery of the diffuser;
the two-stage center cone is axially divided into a first-stage center cone and a second-stage center cone; the first-stage central cone is a head of the central cone, and the tail end of the inner cone surface of the first-stage central cone extends out of the lap joint surface along the direction of the bus; the lap joint surface is provided with a drainage groove along the circumferential direction; the second-stage center cone is a conical sleeve, the small-diameter end of the second-stage center cone is connected with the tail end of the first-stage center cone in a sealing manner, and the large-diameter end of the second-stage center cone is connected with the diffusion section;
the diffusion section is controlled by the driving assembly, can expand outwards along the radial direction, and simultaneously drives the second-stage center cone to slide along the bus direction of the joint surface, so that the on-off control of the drainage groove is completed.
The invention further adopts the technical scheme that: the inner conical surface of the second-stage center cone is provided with a sealing ring, and the sealing ring is used for sealing connection between the small-diameter end of the second-stage center cone and the lap joint surface of the first-stage center cone; when the small diameter end of the second-stage center cone is attached to the tail end of the first-stage center cone, the leakage groove on the joint surface is closed through the sealing ring; when the second-stage center cone slides along the lap joint surface to the lip cover, the leakage groove on the lap joint surface is exposed, namely the leakage groove is opened, and the sealing ring is in sealing connection with the outer edge of the lap joint surface.
The invention further adopts the technical scheme that: the second-stage center cone is coaxially and fixedly connected with the diffusion section, and both the second-stage center cone and the diffusion section are made of memory alloy; under the heating state, the outward expansion force of the driving assembly causes the diffusion section to expand outwards along the radial direction, and simultaneously drives the large-diameter end of the second-stage center cone to expand, thereby changing the throat height.
The invention further adopts the technical scheme that: the drainage grooves are two semicircular through grooves symmetrically arranged on the lap joint surface or a plurality of through holes uniformly distributed along the circumferential direction of the lap joint surface.
The invention further adopts the technical scheme that: the distance between the lip cover and the large diameter end of the second-stage center cone is the height H of the throat th Determined by the altitude and Mach number of flight at cruise of the aircraft; the area calculation formula of the throat is as follows:
wherein A is 0 Is the capture area of the air inlet, sigma is the total pressure recovery coefficient of the air inlet after oblique shock, q (lambda) 0 ) And q (lambda) th ) Solving according to the Mach number of the incoming stream; the throat height of the air inlet channel can be calculated through the throat area obtained through calculation.
The invention further adopts the technical scheme that: at an incoming flow Mach number 0< Ma <2.0, the 1/2 cone angle α of the first stage center cone is 10 °.
The invention further adopts the technical scheme that: the thickness of the sealing ring is smaller than the sloping plate thickness of the second-stage center cone, so that the influence of the addition of the sealing ring on the flow field is negligible.
The invention further adopts the technical scheme that: the sealing ring is made of elastic materials, and the diameter d of the sealing ring is used for ensuring the sealing performance of the second-stage center cone in the moving process 1 The inner diameter d of the lap joint surface of the first-stage center cone is not less than 2 The method comprises the steps of carrying out a first treatment on the surface of the The compression quantity of the initial state of the sealing ring is delta l, and the delta l is increased in the moving process, so that the sealing performance in the moving process is ensured.
The invention further adopts the technical scheme that: the driving assembly comprises a first connecting rod, a second connecting rod and a driver; the first connecting rods are arranged along the axial direction of the diffusion section, the inner ends of the first connecting rods are connected with the driver, the outer ends of the first connecting rods are hinged with one ends of the second connecting rods along the circumferential direction, and the other ends of the second connecting rods are respectively hinged with the inner wall of the diffusion section along the circumferential direction; the first connecting rods are controlled by the driver to move linearly along the axial direction of the diffuser, and one ends of the second connecting rods are driven to move axially along the diffuser, so that pulling force or pressure is applied to the wall surface of the diffuser.
The low-energy fluid control method of the axisymmetric air inlet channel comprises the following steps:
when the Mach number of the incoming flow increases, the driving assembly drives the diffusion section to expand outwards along the radial direction, and simultaneously drives the second-stage center cone and the sealing ring to move outwards along the bus of the lap joint surface of the first-stage center cone, and the throat area is reduced along with the movement of the second-stage center cone, so that the flow discharge groove is changed from a closed state to an open state;
when the Mach number of the incoming flow is reduced, the driving assembly drives the diffusion section to radially converge, and simultaneously drives the second-stage center cone and the sealing ring to move inwards along the generatrix of the lap joint surface of the first-stage center cone, and the throat area is increased along with the movement of the second-stage center cone, so that the flow discharge groove is changed from an open state to a closed state.
Advantageous effects
The invention has the beneficial effects that: according to the axisymmetric air inlet with the flow-discharging groove, the throat area is changed by adjusting the position of the second-stage center cone, so that the performance requirements of the air inlet under different Mach numbers are met, the flow requirement of an engine is larger under the condition of low incoming flow Mach numbers, if the flow-discharging groove is added at the moment, a part of fluid flows out and the flow requirement is not met, and at the moment, the flow-discharging groove is closed by moving the second-stage center cone towards the direction of the first-stage center cone; under high incoming flow Mach number, the flow demand of the engine is smaller, and low-energy fluid can be generated in the air inlet channel under high back pressure due to mutual interference of shock wave boundary layers, and at the moment, the drainage groove is opened by moving the second-stage center cone in a direction away from the first-stage center cone.
The second-stage center cone and the diffusion section of the invention are made of memory alloy, the phase transition temperature of the conventional memory alloy is below 150 ℃, the phase transition temperature belongs to the range of the low-temperature shape memory alloy, the air inlet flight working condition of the invention is 0-11 km, the Ma is 0-2, the temperature is below 117 ℃, and the deformation range of the memory alloy is satisfied.
When the Mach number of the incoming flow is larger than the Mach number of the design point, the outlet of the air inlet needs to meet the condition of subsonic velocity, back pressure is applied to the outlet of the air inlet, low-energy fluid can be generated in the air inlet along with the application of the back pressure, the air inlet cannot be started normally due to insufficient anti-back pressure capacity of the air inlet, and the low-energy fluid in the air inlet can be discharged timely through the flow discharging groove, so that the anti-back pressure capacity of the air inlet is increased, and the pneumatic performance of the air inlet is improved. As shown in fig. 1, the performance of the supersonic air inlet channel added with the drainage channel is compared with that of the supersonic air inlet channel not added with the drainage channel, and as can be seen from the graph, the addition of the drainage channel can timely discharge low-energy fluid in the air inlet channel, and the anti-reverse pressure capability and the total pressure recovery coefficient of the air inlet channel are improved. Table 1 shows the aerodynamic performance of the inlet with/without the bleed slot.
TABLE 1 aerodynamic performance with/without flow grooves
| With/without leakage grooves | Ma | Pressure ratio | Total pressure coefficient of restitution |
| Without any means for | 1.8 | 4.45 | Bow shock wave ejection |
| Has the following components | 1.8 | 4.45 | 95.38％ |
Drawings
FIG. 1 is a comparison of Ma1.8 inlet aerodynamic performance; (a) Ma1.8 pressure ratio 4.45-no drainage groove, (b) Ma1.8 pressure ratio 4.45-drainage groove;
FIG. 2 is an axisymmetric inlet with bleed grooves with adjustable throat area at low incoming Mach numbers;
FIG. 3 is an axisymmetric inlet with bleed grooves with adjustable throat area at high incoming Mach numbers;
reference numerals illustrate: 1. a first stage center cone; 2. a second stage center cone; 3. a seal ring; 4. axisymmetric inlet diffuser sections; 5, a drainage groove; 6. a lip cover; 7. a connecting rod; 8. a hinge; 9. a driver.
Detailed Description
The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention.
Aiming at the problem that the prior art cannot extract the fast developed boundary layer from the air inlet channel, so that the interaction between the boundary layer and shock waves is increased and the anti-reverse pressure capability of the air inlet channel is influenced, the invention designs an axisymmetric air inlet channel which adopts a center cone of a split sealing structure and combines the characteristic of controllable axial linear motion of a second-stage center cone to meet the throat area requirement of the wide-speed-range air inlet channel; the flow discharging groove is coupled with the split center cone, and the opening and closing of the flow discharging groove can be controlled while the throat area is regulated, so that the high flow requirement of the engine under the low incoming flow Mach number is met, and the low-energy fluid in the air inlet channel is discharged under the high incoming flow Mach number.
The axisymmetric air inlet comprises a hollow two-stage center cone, a diffuser connected with the hollow two-stage center cone, and a lip cover arranged on the periphery of the diffuser; the two-stage center cone is axially divided into a first-stage center cone and a second-stage center cone; the first-stage central cone is a head of the central cone, and the tail end of the inner cone surface of the first-stage central cone extends out of the lap joint surface along the direction of the bus; the lap joint surface is provided with a drainage groove along the circumferential direction; the second-stage center cone is a conical sleeve, the small-diameter end of the second-stage center cone is connected with the tail end of the first-stage center cone in a sealing manner, and the large-diameter end of the second-stage center cone is connected with the diffusion section; the diffusion section is controlled by the driving assembly, can expand outwards along the radial direction, and simultaneously drives the second-stage center cone to slide along the bus direction of the joint surface, so that the on-off control of the drainage groove is completed.
The inner conical surface of the second-stage center cone is provided with a sealing ring, and the sealing ring is used for sealing connection between the small-diameter end of the second-stage center cone and the lap joint surface of the first-stage center cone; when the small diameter end of the second-stage center cone is attached to the tail end of the first-stage center cone, the leakage groove on the joint surface is closed through the sealing ring; when the second-stage center cone slides along the lap joint surface to the lip cover, the leakage groove on the lap joint surface is exposed, namely the leakage groove is opened, and the sealing ring is in sealing connection with the outer edge of the lap joint surface. The drainage grooves are two semicircular through grooves symmetrically arranged on the lap joint surface or a plurality of through holes uniformly distributed along the circumferential direction of the lap joint surface.
The second-stage center cone is coaxially and fixedly connected with the diffusion section, and both the second-stage center cone and the diffusion section are made of memory alloy; under the heating state, the outward expansion force of the driving assembly causes the diffusion section to expand outwards along the radial direction, and simultaneously drives the large-diameter end of the second-stage center cone to expand, thereby changing the throat height.
The driving assembly comprises a first connecting rod, a second connecting rod and a driver; the first connecting rods are arranged along the axial direction of the diffusion section, the inner ends of the first connecting rods are connected with the driver, the outer ends of the first connecting rods are hinged with one ends of the second connecting rods along the circumferential direction, and the other ends of the second connecting rods are respectively hinged with the inner wall of the diffusion section along the circumferential direction; the first connecting rods are controlled by the driver to move linearly along the axial direction of the diffuser, and one ends of the second connecting rods are driven to move axially along the diffuser, so that pulling force or pressure is applied to the wall surface of the diffuser.
Preferably, the articulated department of diffuser inner wall is provided with the arc, converts the stress point that the second connecting rod applyed into the stress surface for the diffuser atress is even, and the pressure of second connecting rod makes the diffuser evenly expand outward along circumference, and the pulling force of second connecting rod can restrain the diffuser and expand outward along circumference.
The invention can improve the internal flow field of the wide-speed-range air inlet, timely control low-energy fluid generated by the mutual interference of shock wave boundary layers in the air inlet, improve the total pressure recovery coefficient of the air inlet, and lay a technical foundation for engineering application of the wide-speed-range air inlet and even development of an advanced aircraft.
Examples:
as shown in fig. 2, the invention provides an axisymmetric air inlet with a throat area adjustable and a drainage groove, which comprises a first-stage center cone 1, a second-stage center cone 2, a sealing ring 3, an axisymmetric air inlet diffuser 4, a drainage groove 5, a lip cover 6, a connecting rod 7, a hinge 8 and a driver 9, wherein the connecting rod 7 comprises a first connecting rod and a second connecting rod. The second-stage center cone 2 is fixedly connected with the diffusion section 4, the second-stage center cone 3 is fixedly connected with the sealing ring 3, and the driver 9 is fixedly connected with the first connecting rod and is positioned on the inner side of the center cone. The driver 9 controls the convergence and expansion of the diffusion section 4 to drive the second-stage center cone 2 and the sealing ring 3 to move along the direction of the first-stage center cone, so that the requirement of large flow under low incoming flow Mach number and the requirement of large contraction ratio and high performance under high incoming flow Mach number can be met in the process, and the air inlet channel can keep high pneumatic performance in a wide speed range.
Preferably, the thickness of the sealing ring 3 is less than the thickness of the second-stage central cone sloping plate, so that the influence of the addition of the sealing ring on the flow field is negligible.
Preferably, the sealing ring 3 is made of elastic material, and the diameter d of the sealing ring is used for ensuring the sealing performance of the central cone in the moving process 1 Inner diameter d of the first-stage center cone is not less than 2 . The compression quantity of the initial state of the sealing ring is delta l, and the delta l is increased in the moving process, so that the sealing performance in the moving process is ensured.
Preferably, the second-stage center cone and the diffuser are fixedly connected, and the second-stage center cone and the diffuser are made of memory alloy, and generally, the phase transition temperature of the conventional memory alloy is below 150 ℃, and the conventional memory alloy belongs to the range of low-temperature shape memory alloy.
The length of the second stage center cone 2 is according to the throat height H th To determine throat height H th As determined by the altitude and mach number of the aircraft at cruising. The end position of the second stage center cone determines the throat height H th Throat height is according to the flow conservation formula:
wherein: k is a constant, P * Is the total pressure, T * For total temperature, A 0 Is the capture area of the air inlet channel, A th Is the throat area of the air inlet channel, q (lambda) is the flowAnd the quantity function sigma is the total pressure recovery coefficient of the air inlet channel after oblique shock.
And eliminating the same physical quantity on both sides:
wherein A is 0 Is the capture area of the air inlet, sigma is the total pressure recovery coefficient of the air inlet after oblique shock, q (lambda) 0 ) And q (lambda) th ) The throat area of the air inlet channel can be finally obtained according to the Mach number of the incoming flow, so that the throat height of the air inlet channel can be obtained.
The axisymmetric air inlet with the flow discharging groove with the adjustable throat area has the structure of a first-stage center cone, a second-stage center cone, a sealing ring, a diffusion section and the flow discharging groove as shown in figure 2, wherein the included angle between the first-stage center cone and the horizontal plane is alpha, and under the Mach number of a design point, the flow discharging groove is sealed by shock waves according to the sealing principle and the throat height H th The starting position of the lip mask can be determined.
The low-energy fluid control method of the axisymmetric air inlet passage comprises the following steps:
when the Mach number of the incoming stream is low (Ma<1.2 A smaller constriction ratio is required for the inlet duct, at which point the throat height H th The shock wave/boundary layer interference degree is relatively weak under the high back pressure working condition, the small diameter end of the second-stage center cone is attached to the tail end of the first-stage center cone, and the drainage groove is in a closed state;
along with the increase of the Mach number of the incoming flow, in order to give full play to the thrust performance of the engine, the compression efficiency of the air inlet channel needs to be improved, the required throat area is usually smaller, at the moment, the diffuser section 4 is driven by the control driver 9 to expand outwards along the radial direction, meanwhile, the second-stage center cone 2 and the sealing ring 3 are driven to move outwards along the generatrix of the lap joint surface of the first-stage center cone 1, along with the movement of the second-stage center cone, the sealing ring 3 is always in a compression state, the sealing performance inside the air inlet channel is ensured, and the angle gamma between connecting rods is increased. In the process of adjusting the actuating mechanism, the throat height of the air inlet channel is reduced (as shown in fig. 3), the requirement of large contraction ratio is met, in addition, due to the increase of the incoming flow Mach number, shock waves/boundary layer interference is serious under the high back pressure working condition, a large amount of low-energy fluid is arranged in the air inlet channel, in the process of adjusting, the flow discharging groove 3 is changed from a closed state to an open state, the low-energy fluid in the air inlet channel can be timely discharged, the air inlet channel is prevented from being not started, and the pneumatic heat is well buffered. Through the adjustment of the adjustable mechanism, the air inlet channel can meet the air inlet requirements under different Mach numbers, and low-energy fluid generated by mutual interference of shock wave boundary layers can be discharged under the working condition of high back pressure, so that the pneumatic performance of the air inlet channel and the overall performance of an engine are greatly improved.
Specifically, the axisymmetric air inlet with the flow discharging groove and the adjustable throat area is characterized in that an adjusting mechanism is added on the basis of a traditional non-adjustable axisymmetric air inlet, the design is convenient, the throat area requirement of the air inlet under the wide-speed-range flight is met through a control driver, the problem that low-energy fluid exists in the air inlet under the high-back pressure working condition is solved, the total pressure recovery coefficient of the air inlet is improved to a large extent, and the overall performance requirement of an engine is better met.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations may be made in the above embodiments by those skilled in the art without departing from the spirit and principles of the invention.
Claims (10)
1. An axisymmetric air inlet channel, characterized in that: the device comprises a hollow two-stage center cone, a diffuser connected with the center cone and a lip cover arranged on the periphery of the diffuser;
the two-stage center cone is axially divided into a first-stage center cone and a second-stage center cone; the first-stage central cone is a head of the central cone, the tail end of the inner cone surface of the first-stage central cone extends out of a joint surface along the direction of a bus, and a drainage groove is formed in the joint surface along the circumferential direction; the second-stage center cone is a conical sleeve, the small-diameter end of the second-stage center cone is connected with the tail end of the first-stage center cone in a sealing manner, and the large-diameter end of the second-stage center cone is connected with the diffusion section;
the diffusion section is controlled by the driving assembly, can expand outwards along the radial direction, and simultaneously drives the second-stage center cone to slide along the bus direction of the joint surface, so that the on-off control of the drainage groove is completed.
2. An axisymmetric inlet according to claim 1, characterized in that: the inner conical surface of the second-stage center cone is provided with a sealing ring, and the sealing ring is used for sealing connection between the small-diameter end of the second-stage center cone and the lap joint surface of the first-stage center cone; when the small diameter end of the second-stage center cone is attached to the tail end of the first-stage center cone, the leakage groove on the joint surface is closed through the sealing ring; when the second-stage center cone slides along the lap joint surface to the lip cover, the leakage groove on the lap joint surface is exposed, namely the leakage groove is opened, and the sealing ring is in sealing connection with the outer edge of the lap joint surface.
3. An axisymmetric inlet according to claim 2, characterized in that: the thickness of the sealing ring is smaller than the sloping plate thickness of the second-stage center cone, so that the influence of the addition of the sealing ring on the flow field is negligible.
4. An axisymmetric inlet according to claim 3, characterized in that: the sealing ring is made of elastic materials, and the diameter d of the sealing ring is used for ensuring the sealing performance of the second-stage center cone in the moving process 1 The inner diameter d of the lap joint surface of the first-stage center cone is not less than 2 The method comprises the steps of carrying out a first treatment on the surface of the The compression quantity of the initial state of the sealing ring is delta l, and the delta l is increased in the moving process, so that the sealing performance in the moving process is ensured.
5. An axisymmetric inlet according to claim 1, characterized in that: the second-stage center cone is coaxially and fixedly connected with the diffusion section, and both the second-stage center cone and the diffusion section are made of memory alloy; under the heating state, the outward expansion force of the driving assembly causes the diffusion section to expand outwards along the radial direction, and simultaneously drives the large-diameter end of the second-stage center cone to expand, thereby changing the throat height.
6. An axisymmetric inlet according to claim 1, characterized in that: the drainage grooves are two semicircular through grooves symmetrically arranged on the lap joint surface or a plurality of through holes uniformly distributed along the circumferential direction of the lap joint surface.
7. An axisymmetric inlet according to claim 1, characterized in that: the distance between the lip cover and the large diameter end of the second-stage center cone is the height H of the throat th Determined by the altitude and Mach number of flight at cruise of the aircraft; the area calculation formula of the throat is as follows:
wherein A is 0 Is the capture area of the air inlet, sigma is the total pressure recovery coefficient of the air inlet after oblique shock, q (lambda) 0 ) And q (lambda) th ) Solving according to the Mach number of the incoming stream; the throat height of the air inlet channel can be calculated through the throat area obtained through calculation.
8. An axisymmetric inlet according to claim 1, characterized in that: at an incoming flow Mach number 0< Ma <2.0, the 1/2 cone angle α of the first stage center cone is 10 °.
9. An axisymmetric inlet according to claim 1, characterized in that: the driving assembly comprises a first connecting rod, a second connecting rod and a driver; the first connecting rods are arranged along the axial direction of the diffusion section, the inner ends of the first connecting rods are connected with the driver, the outer ends of the first connecting rods are hinged with one ends of the second connecting rods along the circumferential direction, and the other ends of the second connecting rods are respectively hinged with the inner wall of the diffusion section along the circumferential direction; the first connecting rods are controlled by the driver to move linearly along the axial direction of the diffuser, and one ends of the second connecting rods are driven to move axially along the diffuser, so that pulling force or pressure is applied to the wall surface of the diffuser.
10. A method of low energy fluid control of an axisymmetric inlet according to any of claims 1 to 9, characterized by:
when the Mach number of the incoming flow increases, the driving assembly drives the diffusion section to expand outwards along the radial direction, and simultaneously drives the second-stage center cone and the sealing ring to move outwards along the bus of the lap joint surface of the first-stage center cone, and the throat area is reduced along with the movement of the second-stage center cone, so that the flow discharge groove is changed from a closed state to an open state;
when the Mach number of the incoming flow is reduced, the driving assembly drives the diffusion section to radially converge, and simultaneously drives the second-stage center cone and the sealing ring to move inwards along the generatrix of the lap joint surface of the first-stage center cone, and the throat area is increased along with the movement of the second-stage center cone, so that the flow discharge groove is changed from an open state to a closed state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310743822.8A CN116771561A (en) | 2023-06-23 | 2023-06-23 | Axisymmetric air inlet channel and low-energy fluid control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310743822.8A CN116771561A (en) | 2023-06-23 | 2023-06-23 | Axisymmetric air inlet channel and low-energy fluid control method |
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