CN211370561U - Air inlet channel - Google Patents

Air inlet channel Download PDF

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CN211370561U
CN211370561U CN201922425970.7U CN201922425970U CN211370561U CN 211370561 U CN211370561 U CN 211370561U CN 201922425970 U CN201922425970 U CN 201922425970U CN 211370561 U CN211370561 U CN 211370561U
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air inlet
leading edge
smooth transition
center
blunt leading
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周炳康
李祝飞
杨基明
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University of Science and Technology of China USTC
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University of Science and Technology of China USTC
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Abstract

The utility model discloses an air inlet channel for an engine, which comprises a blunt leading edge, wherein the blunt leading edge comprises a smooth transition section positioned in the center and a straight section connected with the two ends of the smooth transition section; the blunt leading edge is provided with an air inlet and an air outlet, the air inlet and the air outlet are connected through a flow guide channel at the position of the blunt leading edge, and the distance between the air inlet and the center of the smooth transition section is smaller than that between the air outlet and the center of the smooth transition section. In the blunt leading edge that this application provided, through set up the water conservancy diversion passageway at blunt leading edge, utilize the static pressure difference of low reaches on the flow field, need not extra power device and energy supply system, can realize flowing self-loopa, simple structure realizes easily, with high-pressure department air current direction low pressure department position, has reduced the distance of smooth transition section center department shock wave to the wall, has effectively reduced blunt leading edge wall pressure, heat flow load peak value, and then has improved the intake duct performance.

Description

Air inlet channel
Technical Field
The utility model relates to a high mach number pneumatic technology field, in particular to intake duct.
Background
The high mach number aircraft has extremely important military and civil values, the scramjet engine is one of the most potential power modes for realizing high-speed flight, and the air inlet channel is used as an important part of the scramjet engine, and the performance of the air inlet channel is directly related to the efficiency of the whole propulsion system. In recent years, an inward-turning intake duct using a combination of curved shock waves and isentropic compression has attracted much attention because of its excellent performance such as high airflow compression ratio and low total pressure loss.
However, due to the high backswept of the front edge of the inward-rotation type air inlet, a V-shaped overflow port is formed at the intersection position of the root part of the front edge. In practical designs, the leading edge of the inlet exposed to high mach number flow needs to be passivated to some extent for aerodynamic thermal protection and structural strength. However, after the front edge of the air inlet passage is passivated, the shock wave is not attached, a complex wave system structure is generated near the overflow port due to the appearance of the detached shock wave, and meanwhile, the wall pressure, the heat flow and the unsteady oscillation of the flow can be caused, so that the structural strength of the overflow port of the air inlet passage is seriously challenged, and the performance of the air inlet passage is influenced.
Therefore, how to improve the performance of the engine intake duct is an urgent technical problem to be solved by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an intake duct to improve the intake duct performance.
In order to achieve the purpose, the utility model provides an air inlet channel which is used for an engine and comprises a blunt leading edge, wherein the blunt leading edge comprises a smooth transition section positioned in the center and a straight section connected with the two ends of the smooth transition section;
the blunt leading edge is provided with an air inlet and an air outlet, the air inlet is connected with the air outlet through a flow guide channel at the position of the blunt leading edge, and the distance between the air inlet and the center of the smooth transition section is smaller than that between the air outlet and the center of the smooth transition section.
Preferably, the number of the flow guide channels is two, and the two flow guide channels are respectively arranged on two opposite sides of the center line of the blunt leading edge.
Preferably, two said diversion passages share one said air inlet, said air inlet is located at the center of said smooth transition section.
Preferably, the center line of the smooth transition section is in a circular arc structure.
Preferably, the air inlet, the air outlet and the flow guide channel are all circular-section pipelines.
Preferably, the diameter D of the air inlet1Satisfies the following conditions:
0.3r≤D1≤0.4r;
two the gas outlet distributes the relative both sides of central line of blunt leading edge, and be the symmetric distribution, the gas outlet with the water conservancy diversion passageway is the uniform cross section pipeline, the gas outlet with the diameter D of water conservancy diversion passageway2Satisfies the following conditions:
Figure BDA0002342017690000021
where r is the passivation radius of the blunt leading edge.
Preferably, the air outlet is located at the junction of the straight section and the smooth transition section, and the horizontal distance L between the center of the air outlet and the center of the smooth transition section1Satisfies the following conditions:
0.2r≤L1≤8r。
preferably, the connection part of the air inlet and the flow guide channel is connected through a variable-section circular pipeline;
the horizontal distance L between the center of the air inlet and the starting point of the connection part of the flow guide channel2Satisfies the following conditions:
0.3r≤L2≤1r;
where r is the passivation radius of the blunt leading edge.
Preferably, the flow guide channel and the air inlet and the air outlet are smoothly transited through rounding;
radius R of transition of the air inlet and the flow guide channel1Satisfies the following conditions:
0.2r≤R1≤1r;
where r is the passivation radius of the blunt leading edge.
Preferably, the rounding radius R at the transition of the air outlet and the flow guide channel2Satisfies the following conditions:
0.5r≤R2≤4r。
in the technical scheme, the utility model provides an intake duct for the engine, including blunt leading edge, blunt leading edge reaches the straight section that links up with smooth transition section both ends including the smooth transition section that is located the center. The blunt leading edge is provided with an air inlet and an air outlet, the air inlet and the air outlet are connected through a flow guide channel at the blunt leading edge, and the distance between the air inlet and the center of the smooth transition section is smaller than the distance between the air outlet and the center of the smooth transition section. When the engine works, near the center of the smooth transition section, the shock wave interference is complex, and the pressure is high; upstream of the smooth transition, the pressure is lower; and (3) pumping high-pressure airflow at the center of the smooth transition section away from the air inlet by utilizing static pressure difference between the upstream and the downstream of the flow field, and re-ejecting the airflow from the air outlet at the position with lower upstream pressure through the flow guide channel to realize a self-circulation flow control loop.
According to the description, in the air inlet provided by the application, the flow guide channel is formed in the blunt front edge, the flow self-circulation can be realized by utilizing the static pressure difference of the upper and lower streams of the flow field without an additional power device and an energy supply system, the structure is simple, the realization is easy, the air flow at the high pressure part is guided to the position at the low pressure part, the distance from the shock wave at the center of the smooth transition section to the wall surface is reduced, the wall surface pressure of the blunt front edge and the heat flow load peak value are effectively reduced, and the performance of the air inlet is further improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is an isometric view of a blunt leading edge provided by an embodiment of the present invention;
FIG. 2 is a cross-sectional view in a span-wise direction of a blunt leading edge provided by an embodiment of the present invention;
FIG. 3 is an enlarged view of portion A of FIG. 2;
FIG. 4 is a comparison of a conventional Mach number cloud plot of a blunt leading edge with a conventional blunt leading edge symmetry plane provided by the present invention;
FIG. 5 is a comparison of the blunt leading edge provided by the present invention versus the conventional blunt leading edge centerline wall pressure;
figure 6 the present invention provides a comparison of blunt leading edge and conventional blunt leading edge centerline wall heat flow.
Wherein in FIGS. 1-3: 1-air inlet, 2-air outlet, 3-flow guide channel, 4-straight section and 5-smooth transition section.
Detailed Description
The core of the utility model is to provide an air inlet channel to improve the air inlet channel performance.
In order to make those skilled in the art better understand the technical solution of the present invention, the present invention will be further described in detail with reference to the accompanying drawings and embodiments.
Please refer to fig. 1 to fig. 6.
In a specific implementation manner, the air intake duct provided by the embodiment of the present invention is used for an engine, and includes a blunt leading edge, where the blunt leading edge includes a smooth transition section 5 located at the center and a straight section 4 connected with two ends of the smooth transition section; the blunt leading edge is provided with an air inlet 1 and an air outlet 2, the air inlet 1 and the air outlet 2 are connected through a flow guide channel 3 at the blunt leading edge, and the distance between the air inlet 1 and the center of the smooth transition section 5 is smaller than the distance between the air outlet 2 and the center of the smooth transition section 5. As shown in fig. 1 and fig. 3, the blunt front edge is a plate structure, so as to facilitate the display of the positions of the flow guide channel, the air inlet and the air outlet.
Preferably, the gas inlet 1 is arranged at the central position of the smooth transition section 5, and the gas outlet 2 is arranged at the position where the smooth transition section 5 or the straight section 4 is connected with the smooth transition section 5.
The air inlet 1 is vertical to the wall surface of the opening position of the smooth transition section 5, and the air outlet 2 is along the direction of a spanwise coordinate (z axis).
When the engine works, near the center of the smooth transition section 5, the shock wave interference is complex, and the pressure is high; upstream of the smooth transition 5, the pressure is lower; by utilizing static pressure difference of the upper and lower streams of the flow field, high-pressure airflow at the center of the smooth transition section 5 is pumped out from the air inlet 1 and is re-sprayed out from the air outlet 2 at the position with lower pressure of the upper stream through the flow guide channel 3, so that a self-circulation flow control loop is realized.
As can be seen from the above description, in the air inlet provided in the embodiment of the present application, the flow guide channel 3 is formed on the blunt front edge, and the static pressure difference between the upstream and downstream of the flow field is utilized to draw the high-pressure air flow at the center of the smooth transition section 5 away from the air inlet 1, and the high-pressure air flow passes through the flow guide channel 3 and is re-ejected from the air outlet 2 at the position with lower upstream pressure, so that the flow self-circulation can be achieved without an additional power device. The flow self-circulation can be realized without an extra power device and an energy supply system, the structure is simple, the realization is easy, the air flow at the high pressure part is guided to the position at the low pressure part, the distance from the shock wave at the center of the smooth transition section 5 to the wall surface is reduced, the wall surface pressure of the blunt leading edge and the heat flow load peak value are effectively reduced, and the performance of the air inlet channel is further improved.
Preferably, there are two flow guide channels 3, and the two flow guide channels 3 are respectively arranged on two opposite sides of the centerline position of the blunt leading edge.
In one specific implementation method, two flow guide channels 3 share one air inlet 1, and the air inlet 1 is positioned in the center of the smooth transition section 5.
Specifically, the center line of the smooth transition section 5 is an arc line structure, specifically, an arc. Alternatively, the shape of the center line of the smooth transition section 5 is an elliptical structure, a hyperbolic shape, a parabolic shape, or the like.
In one embodiment, the gas inlet 1, the gas outlet 2 and the flow guide channel 3 are all circular cross-section pipes.
In one embodiment, the flow guide channel and the air inlet 1 and the air outlet 2 are smoothly transited through rounding;
radius R of transition between air inlet 1 and flow guide channel 31Satisfies the following conditions:
0.2r≤R1≤1r;
radius R of transition between air outlet 2 and flow guide channel 32Satisfies the following conditions:
0.5r≤R2≤4r;
r is the passivation radius of the blunt leading edge.
In one embodiment, the diameter D of the gas inlet 11Satisfies the following conditions:
0.3r≤D1not more than 0.4r, in particular, D1May be 0.35 r.
Where r is the passivation radius of the blunt leading edge.
Specifically, the air outlet 2 and the flow guide channel 3 are equal-section pipelines, and the diameters D of the air outlet 2 and the flow guide channel 32Satisfies the following conditions:
Figure BDA0002342017690000051
the gas outlet 2 is positioned at the joint of the straight section and the smooth transition section 5, and the horizontal distance L between the center of the gas outlet 2 and the center of the smooth transition section 51Satisfies the following conditions:
0.2r≤L1l is not more than 8r, specifically, not more than 0.4r1≤0.6r,
r is the passivation radius of the blunt leading edge.
The center of the air inlet 1 is connected with two starting points of the flow guide channel 3 through a variable-section circular pipeline.
In one specific embodiment, the connection part of the air inlet 1 and the flow guide channel 3 is connected through a variable-section circular pipeline;
horizontal distance L between the center of the air inlet 1 and the air inlet end of the flow guide channel 32Satisfies the following conditions:
0.3r≤L2l is not more than 1r, specifically, not more than 0.5r2≤0.8r。
Where r is the passivation radius of the blunt leading edge.
In one embodiment, referring to fig. 3, the design parameters of the automatic circulation flow control device of the present example are: diameter D of the gas inlet 110.4r, the diameter D of the air outlet 2 and the flow guide channel 320.283r, the horizontal distance L between the center of the air outlet 2 and the center of the smooth transition section 511.9r, the horizontal distance L between the center of the air inlet 1 and the air inlet end of the diversion channel 32Radius R of the transition between the inlet 1 and the flow channel 3 is 0.3R1Radius R of transition between the air outlet 2 and the flow guide channel 3 is 0.4R20.5r, where r is the leading edge passivation radius. The control effect of this example is illustrated by numerical simulations as follows:
FIG. 4 is a graph showing a Mach number cloud comparison of the blunt leading edge symmetric surface with the flow control device of the present application compared to the conventional flow control device, wherein the incoming flow Mach number is 6 and the incoming flow direction is from left to right; as can be seen from the flow lines in fig. 4, the air flow does enter from the air inlet 1 of the control device, flows through the flow guide channel 3 and then is ejected from the air outlet 2; the distance from the shock wave to the wall at the center of the smooth transition 5 is reduced by about 33% with flow control compared to the case without flow control.
Figure 5 shows the comparison of the pressure at the centerline of the blunt leading edge with flow control in the flow channel 3 compared to the conventional flow control without flow control, with the horizontal axis representing the spanwise coordinate divided by the radius of the leading edge passivation and the vertical axis representing the local pressure divided by the incoming flow static pressure, and in the figure the solid line shows the results without flow control and the dotted line shows the results with flow control. As can be seen from fig. 5, there is a distinct peak in the wall pressure distribution between the inlet port 1 and the outlet port 2, and the pressure peak drops by about 28% after flow control. That is to say, the utility model discloses blunt leading edge automatic circulation flow control device has effectively reduced blunt leading edge wall pressure load peak value.
FIG. 6 illustrates the comparison of the blunt leading edge centerline wall heat flow with conventional flow control versus conventional flow control without, with the horizontal axis being the spanwise coordinate divided by the leading edge passivation radius and the vertical axis being the local heat flow divided by the theoretical value of the stagnation point heat flow for a cylinder of the same passivation radius, with the solid line indicating the results of the non-use of flow control and the dotted line indicating the results of the use of flow control. It can be seen from fig. 6 that there is also a significant peak in the wall heat flow distribution between inlet 1 and outlet 2, whereas with flow control the peak heat flow load is reduced by about 27%. Therefore, the control effect is obvious.
When the device works, near the center of the smooth transition section 5, the shock wave interference is complex, and the pressure is high; upstream of the smooth transition 5, the pressure is lower; by utilizing static pressure difference of the upper and lower streams of the flow field, high-pressure airflow at the center of the smooth transition section 5 is pumped out from the air inlet 1 and is re-sprayed out from the air outlet 2 at the position with lower pressure of the upper stream through the flow guide channel 3, so that a self-circulation flow control loop is realized. In addition, the cross section of the flow guide channel 3 is circular, so that the structure is slightly damaged, the length of the flow guide channel 3 is short, the complexity of the device is reduced, and the flowing smoothness is improved; the two flow guide channels 3 are designed in an up-and-down symmetrical mode, the sectional area of an inlet is the sum of the sectional areas of the upper outlet and the lower outlet, and the flowing smoothness is further improved.
By the above-mentioned the technical scheme provided by the utility model, the utility model provides an obtuse leading edge automatic circulation control device utilizes the static pressure difference in low reaches on the flow field, need not extra power device and energy supply system, can realize flowing self-loopa, and simple structure realizes easily. On the premise of not changing the geometrical characteristics of the blunt leading edge, the distance from the shock wave at the center of the smooth transition section 5 to the wall surface is obviously reduced, and the pressure and the heat flow load peak value of the wall surface of the blunt leading edge are effectively reduced. In addition, the automatic circulation flow control device has wide application range and can be realized aiming at blunt leading edges with different geometric characteristics.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. An air inlet channel for an engine, characterized by comprising a blunt leading edge, wherein the blunt leading edge comprises a smooth transition section (5) at the center and a straight section (4) connected with two ends of the smooth transition section;
air inlet (1) and gas outlet (2) have been seted up on the blunt leading edge, air inlet (1) with gas outlet (2) pass through water conservancy diversion passageway (3) that the blunt leading edge position is connected, air inlet (1) with the distance at smooth transition section (5) center is less than gas outlet (2) with the distance at smooth transition section (5) center.
2. The air inlet according to claim 1, characterized in that the number of the flow guide channels (3) is two, and the two flow guide channels (3) are respectively arranged on two opposite sides of the centerline position of the blunt leading edge.
3. The intake duct according to claim 1, characterized in that two of the flow-guiding channels (3) share one of the intake openings (1), and the intake opening (1) is located in the center of the smooth transition section (5).
4. The intake duct according to claim 1, characterized in that the centre line of the smooth transition (5) is of circular arc configuration.
5. Air inlet duct according to claim 1, characterized in that the air inlet (1), the air outlet (2) and the flow guide channel (3) are all circular-section ducts.
6. Air intake duct according to claim 5, characterized in that the diameter D of the air intake opening (1)1Satisfies the following conditions:
0.3r≤D1≤0.4r;
two gas outlets (2) are distributed on two opposite sides of the center line of the blunt front edge and are symmetrically distributed, the gas outlets (2) and the flow guide channel (3) are equal-section pipelines, and the gas outlets(2) And the diameter D of the flow guide channel (3)2Satisfies the following conditions:
Figure FDA0002342017680000011
where r is the passivation radius of the blunt leading edge.
7. The air inlet according to claim 6, characterized in that the air outlet (2) is located at the junction of the straight section (4) and the smooth transition section (5), and the horizontal distance L between the center of the air outlet (2) and the center of the smooth transition section (5)1Satisfies the following conditions:
0.2r≤L1≤8r。
8. the air inlet duct according to claim 1, characterized in that the connection of the air inlet (1) and the flow guide channel (3) is connected by a variable cross-section circular duct;
the horizontal distance L of the starting point of the joint of the center of the air inlet (1) and the flow guide channel (3)2Satisfies the following conditions:
0.3r≤L2≤1r;
where r is the passivation radius of the blunt leading edge.
9. The air inlet according to claim 1, characterized in that the flow guide channel (3) and the air inlet (1) and the air outlet (2) are smoothly transited by rounding;
the radius R of the transition between the air inlet (1) and the flow guide channel (3)1Satisfies the following conditions:
0.2r≤R1≤1r;
where r is the passivation radius of the blunt leading edge.
10. Air inlet according to claim 9, characterized in that the outlet opening (2) merges with the flow guide channel (3) with a rounding radius R2Satisfies the following conditions:
0.5r≤R2≤4r。
CN201922425970.7U 2019-12-27 2019-12-27 Air inlet channel Active CN211370561U (en)

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Application Number Priority Date Filing Date Title
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Publications (1)

Publication Number Publication Date
CN211370561U true CN211370561U (en) 2020-08-28

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