CN111173619B - Inward-rotating air inlet channel and V-shaped blunt front edge thereof - Google Patents

Abstract

The invention discloses a V-shaped blunt leading edge of an inward turning type air inlet channel, which comprises a conical curve section and a straight leading edge section; the number of the straight front edge sections is two, and the straight front edge sections and the two straight front edge sections are respectively connected with the two ends of the conical curve section in a smooth tangent way to form a V shape; the passivation radius at the central position of the conical curve section is r1, the passivation radius at the position of the tangent point of the conical curve section and the straight front edge section is r2, wherein r1 is larger than r2, and the passivation radius of the front edge of the conical curve section continuously decreases from the central position to the tangent points at the two sides. In the V-shaped blunt leading edge, the radius of the tapered curve segment continuously decreases from the center position to the leading edge at the two ends, and the severe aerodynamic heat caused by stagnation of the airflow at the center point is relieved. The invention also discloses an inward-rotating air inlet channel, and the application of the V-shaped passivation front edge is beneficial to relieving aerodynamic heat.

Description

Inward-turning air intake and its V-shaped blunt leading edge

Technical Field

The present invention relates to the technical field of mechanical industry, and more specifically, to an inward-turning air inlet, and also to a V-shaped blunt leading edge of the inward-turning air inlet.

Background Art

The hypersonic inlet captures the incoming flow and decelerates and pressurizes it, and is one of the important aerodynamic components of the scramjet engine. The three-dimensional inward-rotating inlet has attracted extensive attention at home and abroad due to its advantages such as strong airflow capture capability, high compression efficiency and convenient integrated design.

The leading edge of the inner-turning air inlet is usually designed as a V-shaped structure to improve the starting ability of the air inlet under low Mach number inflow conditions. Considering the aerodynamic thermal protection and structural safety performance, the prior art makes a uniform blunt design for the V-shaped leading edge. However, in the existing V-shaped blunt leading edge, the root of the V is the airflow stagnation point, which will cause severe aerodynamic heat.

Therefore, how to alleviate the aerodynamic thermal environment at the root of the V-shape in the V-shaped blunt leading edge is a problem that needs to be solved urgently by those skilled in the art.

Summary of the invention

In view of this, the present invention provides a V-shaped blunt leading edge of an inward-turning air inlet, wherein the leading edge blunt radius in the conical curve section continuously decreases from the center position to the two ends, thereby alleviating the severe aerodynamic heat caused by the stagnation of the airflow at the center point. The present invention also provides an inward-turning air inlet, which uses the above-mentioned V-shaped blunt leading edge, which is beneficial to alleviating aerodynamic heat.

To achieve the above object, the present invention provides the following technical solutions:

A V-shaped blunt leading edge of an inward-turning air inlet, comprising:

conic section,

There are two straight front edge segments, and the two straight front edge segments are smoothly tangently connected to two ends of the conic curve segment to form a "V" shape;

The blunt radius at the center position of the conic section is r1, and the blunt radius at the tangent point of the conic section with the straight leading edge section is r2, wherein r1>r2, and the leading edge blunt radius of the conic section decreases continuously from the center position to the tangent points on both sides.

Preferably, in the above-mentioned V-shaped blunt leading edge, the center line of the conic curve segment is a conic curve or a quasi-conic curve.

Preferably, in the above-mentioned V-shaped blunt leading edge, the blunt leading edge of the conic curve segment is a blunt leading edge obtained by performing non-uniform rounding and blunting treatment with the center line of the conic curve segment as the outline.

Preferably, in the V-shaped blunt leading edge, the leading edge blunting radius r of the conic curve segment from the center position to the tangent points on both sides varies along the center line according to the following formula:

r＝r ₂ +(r ₁ -r ₂ )[sinφ] ⁿ

in, is the angle between the tangent direction of the center line and the incoming flow direction; 0.5<n<10; θ is the half angle of the two straight leading edge segments.

Preferably, in the above-mentioned V-shaped blunt leading edge, the half angle satisfies: 12°<θ<65°.

Preferably, in the above-mentioned V-shaped blunt leading edge, the two straight leading edge segments are symmetrically arranged.

Preferably, in the above-mentioned V-shaped blunt leading edge, the center line of the straight leading edge segment is a straight line segment symmetrical on both sides; the blunt leading edge of the straight leading edge segment is a blunt leading edge obtained by uniformly chamfering and passivating the center line of the straight leading edge segment as the outline, and the passivation radius is equal to r2.

An inward-turning air inlet, characterized in that it comprises a V-shaped blunt leading edge, wherein the V-shaped blunt leading edge is the V-shaped blunt leading edge described in any one of the above technical solutions.

The present invention provides a V-shaped blunt leading edge of an inward-turning air inlet, comprising a conic curve segment and a straight leading edge segment; there are two straight leading edge segments, and the two straight leading edge segments are smoothly tangently connected to the two ends of the conic curve segment respectively to form a "V" shape; the blunt radius at the center position of the conic curve segment is r1, and the blunt radius at the tangent point position of the conic curve segment and the straight leading edge segment is r2, wherein r1>r2, and the leading edge blunt radius of the conic curve segment continuously decreases from the center position to the tangent points on both sides.

The invention provides a V-shaped blunt leading edge, in which the blunting radius of the leading edge in the conic curve section decreases continuously from the center position to the two ends, so as to alleviate the severe aerodynamic heat caused by the stagnation of the airflow at the center point.

The present invention also provides an inward-turning air inlet, which uses the above-mentioned V-shaped passivated leading edge, which is beneficial to alleviating aerodynamic heat.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

FIG1 is an axonometric view of a V-shaped blunt leading edge provided by an embodiment of the present invention;

FIG2 is a front view of a V-shaped blunt leading edge provided by an embodiment of the present invention;

Fig. 3 is a cross-sectional view taken along line A-A in Fig. 2;

Fig. 4 is a cross-sectional view taken along line B-B in Fig. 2;

FIG5 is a left side view of a V-shaped blunt leading edge provided by an embodiment of the present invention;

FIG6 is a numerical schlieren diagram of the x-z symmetric plane and a wall heat flow cloud diagram of a uniformly passivated V-shaped blunt leading edge provided by an embodiment of the present invention;

FIG7 is a numerical schlieren diagram of an x-z symmetric plane and a wall heat flow cloud diagram provided by an embodiment of the present invention;

FIG8 is a diagram showing the pressure distribution along the center line of the conic curve segment wall of a V-shaped blunt leading edge and a uniformly blunted V-shaped blunt leading edge provided by an embodiment of the present invention;

9 is a heat flux distribution diagram of a V-shaped blunt leading edge and a uniformly passivated V-shaped blunt leading edge along the center line of the conic curve segment wall provided by an embodiment of the present invention;

Among them, in Figures 1 to 5:

Conic section 1; straight leading edge section 2.

DETAILED DESCRIPTION

The embodiment of the present invention discloses a V-shaped blunt leading edge of an inward-turning air inlet, wherein the leading edge blunt radius of the conic curve section decreases continuously from the center position to the two ends, thereby alleviating the severe aerodynamic heat caused by the stagnation of the airflow at the center point. The embodiment of the present invention also discloses an inward-turning air inlet, which is beneficial to alleviating the aerodynamic heat by applying the V-shaped blunt leading edge.

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

Please refer to Figures 1 to 9. An embodiment of the present invention provides a V-shaped blunt leading edge of an inward-turning air inlet, including a conical curve segment 1 and a straight leading edge segment 2; there are two straight leading edge segments 2, and the two are smoothly tangently connected to the two ends of the conical curve segment 1 respectively (that is, a smooth transition is made from the connection between the conical curve segment 1 and the straight leading edge segment 2, and the extension direction of the straight leading edge segment 2 is tangent to the end of the conical curve segment 1 that matches it), forming a "V" shape; the blunting radius at the center position of the conical curve segment 1 (that is, the root center point position of the V-shaped blunt leading edge) is r1, and the blunting radius at the tangent point position of the conical curve segment 1 and the straight leading edge segment 2 is r2, wherein r1>r2, and the leading edge blunting radius of the conical curve segment 1 continuously decreases from the center position to the tangent points on both sides (that is, the connection between the end of the conical curve segment 1 and the straight leading edge segment 2).

The embodiment of the present invention provides a V-shaped blunt leading edge, in which the leading edge blunting radius of the conic curve section 1 decreases continuously from the center position to the two ends, thereby alleviating the severe aerodynamic heat caused by the stagnation of the airflow at the center point.

Specifically, in the V-shaped blunt leading edge, the center line of the conic curve segment 1 is a conic curve or a quasi-conic curve. The blunt leading edge of the conic curve segment 1 is a blunt leading edge obtained by performing non-uniform rounding and blunting treatment on the center line of the conic curve segment 1 as the outline.

The leading edge blunting radius r of the conic curve segment 1 from the center position to the tangent points on both sides varies along the center line according to the following formula:

r＝r ₂ +(r ₁ -r ₂ )[sinφ] ⁿ

in, is the angle between the centerline tangent direction and the horizontal incoming flow direction, as shown in FIG2 ; 0.5<n<10; θ is the half angle of the two straight leading edge segments 2 .

In the V-shaped blunt leading edge provided in the above embodiment, the half angle θ of the two straight leading edge segments 2 satisfies: 12°<θ<65°.

The two straight leading edge segments 2 are arranged symmetrically, that is, the center lines of the two straight leading edge segments 2 are straight line segments symmetrical to each other on both sides of the x-y plane, as shown in Figure 1; the blunt leading edge of the straight leading edge segment 2 is a blunt leading edge obtained by uniformly chamfering and passivating the center line of the straight leading edge segment 2 as the outline, and the passivation radius is equal to r2.

The operating principle of the V-shaped blunt leading edge provided by the embodiment of the present invention is as follows:

1. The shock wave interference at the root of conic curve section 1 is complex and the aerodynamic thermal environment is harsh. Reasonably setting a larger blunting radius r1 at the center point of the V-shaped blunt leading edge root can alleviate the severe aerodynamic heat caused by the stagnation of airflow at the center point;

2. The aerodynamic thermal environment faced by the swept straight leading edge section 2 is relatively not harsh, and a smaller straight leading edge section 2 blunting radius r2 can be used to reduce resistance and improve aerodynamic performance.

3. The detached shock wave generated by the straight leading edge section 2 intersects and interferes with the shock wave generated by the V-shaped root, transmitting the shock wave of the incident wall; starting from the tangent point of the straight leading edge section 2 and the conic section 1, the airflow direction near the wall of the conic section 1 is continuously deflected, generating a series of compression waves. According to the analysis of shock wave interference theory, the shock wave intensity of the incident wall can be weakened by allowing the shock wave of the incident wall to intersect with the above-mentioned compression wave on the same side, thereby reducing the aerodynamic force/thermal load on the wall. In addition, the straight leading edge section 2 uses a smaller blunting radius r2, and the detached shock wave generated by the straight leading edge section 2 is closer to the wall, which increases the airflow leakage efficiency and reduces the accumulation of airflow along the straight leading edge section 2 to the V-shaped root, making the shock wave generated by the V-shaped root closer to the wall, and the shock wave of the incident wall intersects with the above-mentioned compression wave on the same side. The range is larger, further weakening the shock wave intensity of the incident wall, thereby greatly reducing the aerodynamic force/thermal load on the wall.

The V-shaped blunt leading edge provided in this embodiment has the following beneficial effects:

1. Under the conditions that the passivation radius r1 at the center point of the V-shaped root and the incoming flow conditions are the same, the non-uniformly passivated V-shaped blunt leading edge provided by this embodiment has significantly lower wall pressure and heat flux peak values compared with the conventional uniformly passivated V-shaped blunt leading edge;

2. This embodiment uses a conic curve or a quasi-conic curve as the center line of the conic curve segment 1, and the contraction transition of the wall surface is smooth, so that the process of airflow converging to the root of the V-shaped blunt leading edge is as gentle as possible, avoiding the generation of a more complex shock wave interference structure;

3. This embodiment only adjusts the blunt radius of the V-shaped blunt leading edge, which has a simple structure, is easy to implement, has a low manufacturing cost, and is easy to use.

The V-shaped blunt leading edge is described below with a specific embodiment:

The design parameters of the non-uniformly blunted V-shaped blunt leading edge in this embodiment are: the center line of the conic curve segment is an arc with a curvature radius of 6.5 mm, the blunt radius r1 at the center point of the V-shaped root is 2 mm, the blunt radius r2 at the tangent point and the straight leading edge segment is 1 mm, the blunt radius from the center point of the V-shaped root to the tangent point gradually decreases, the leading edge half angle θ is 24°, the incoming flow Mach number Ma is 6, the static temperature T is 115K, and the static pressure P is 800Pa.

As a comparison with the present embodiment, the design parameters of the conventional uniformly passivated V-shaped blunt leading edge are: the center line of the conic curve segment is an arc with a curvature radius of 6.5 mm, the passivation radius of the conic curve segment and the straight leading edge segment is uniform and unchanged, r1=r2=2 mm, the leading edge half angle θ=24°, the incoming flow Mach number Ma=6, the static temperature T=115 K, and the static pressure P=800 Pa. Attached Figure 6 shows the numerical schlieren diagram of the x-z symmetric plane of the root of the uniformly passivated V-shaped blunt leading edge and the wall heat flow cloud diagram, wherein the wall heat flow is dimensionless by dividing the local heat flow by the theoretical heat flow value of the center point of the V-shaped root. It can be seen from Figure 6 that the heat flux at the center point of the V-shaped root is relatively high; complex shock wave interference occurs on both sides of the conic curve segment, and the transmitted shock waves generated by the shock wave interference on both sides are incident on the wall, and the wall heat flux near the shock wave incident point increases sharply; the aerodynamic thermal environment faced by the swept straight leading edge segment is relatively not harsh; starting from the tangent point of the straight leading edge segment and the conic curve segment, a series of compression waves are generated near the wall of the conic curve segment.

Attached Figure 7 shows the numerical schlieren diagram of the x-z symmetric plane and the wall heat flow cloud diagram of the non-uniformly passivated V-shaped blunt leading edge of this embodiment, wherein the wall heat flow is dimensionless by dividing the local heat flow by the theoretical heat flow value of the center point of the V-shaped root. By comparing Attached Figures 6 and 7, it can be seen that under the same conditions of the center line of the V-shaped root, the passivation radius r1 at the center point of the V-shaped root, and the incoming flow conditions, the accumulated amount of airflow at the V-shaped root is reduced after adopting this embodiment, and the detached shock wave generated by the straight leading edge section and the shock wave generated by the V-shaped root are closer to the wall; on both sides of the conic curve section, the shock wave transmitted by the shock wave interference intersects with the compression wave near the wall of the conic curve section on the same side in a larger range before it is incident on the wall.

FIG8 shows the pressure comparison on the center line of the conic curve segment wall of the present embodiment and the uniformly blunt V-shaped blunt leading edge, the horizontal axis is the circumferential angle along the arc center line, and the vertical axis is the dimensionless pressure after the local pressure is divided by the theoretical value of the pressure at the center point of the V-shaped root. As can be seen from FIG8, compared with the uniformly blunt V-shaped blunt leading edge, the maximum pressure after adopting the present embodiment decreases by about 47%. By adopting the design of the present invention, the shock wave intensity of the incident wall can be weakened, and the pressure load on the blunt leading edge wall can be effectively reduced.

Attached Figure 9 shows a heat flux comparison between the present embodiment and the uniformly passivated V-shaped blunt leading edge conic curve segment wall centerline, the horizontal axis is the circumferential angle along the arc centerline, and the vertical axis is the dimensionless heat flux after the local heat flux is divided by the theoretical value of the heat flux at the center point of the V-shaped root. As can be seen from Figure 9, compared with the uniformly passivated V-shaped blunt leading edge, due to the reduction in the straight leading edge passivation radius of the present embodiment, the heat flux value near the tangent point position (66°) on both sides increases slightly, but the aerodynamic thermal environment is relatively not harsh. Compared with the uniformly passivated V-shaped blunt leading edge, the maximum heat flux of the present embodiment decreases by about 43%. By adopting the design of the present invention, the heat flux load on the blunt leading edge wall can be effectively reduced.

An embodiment of the present invention provides an inward-turning air inlet, comprising a V-shaped blunt leading edge, wherein the V-shaped blunt leading edge is the V-shaped blunt leading edge provided in the above embodiment.

The inward-turning air intake provided in this embodiment uses the V-shaped blunt leading edge, which is beneficial to relieving aerodynamic heat. Of course, the inward-turning air intake provided in this embodiment also has other effects related to the V-shaped blunt leading edge provided in the above embodiments, which will not be repeated here.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims (4)

1. A V-shaped blunt leading edge for an internal transfer air inlet, comprising:

The conical curve section is provided with a plurality of concave curve sections,

The straight front edge sections are two and are respectively and smoothly tangent to the two ends of the conical curve section to form a V shape; the two straight front edge sections are symmetrically arranged;

The passivation radius at the central position of the conical curve section is r ₁, the passivation radius at the tangential point position of the conical curve section and the straight front edge section is r ₂, wherein r ₁ > r₂, the front edge passivation radius of the conical curve section continuously decreases from the central position to tangential points at two sides;

The blunt leading edge of the conical curve section is obtained by taking the central line of the conical curve section as a contour and carrying out non-uniform rounding passivation treatment;

the front edge passivation radius r of the conical curve section from the center position to the tangential point positions on the two sides is changed along the center line according to the following formula:

wherein phi is an included angle between the tangential direction of the central line and the incoming flow direction; 0.5 < n < 10; θ is the half angle of the two straight leading edge segments;

The central line of the straight front edge section is a straight line section with two symmetrical sides; the blunt leading edge of the straight leading edge section is obtained by uniformly rounding and passivating the central line of the straight leading edge section serving as a contour, and the passivating radius is equal to r ₂.

2. The V-shaped blunt leading edge of claim 1 wherein the centerline of the conic curve segment is a conic curve.

3. The V-shaped blunt leading edge according to claim 1, wherein said half-angle satisfies: 12 ° < θ < 65 °.

4. An internal-rotation type air inlet channel, which comprises a V-shaped blunt front edge, wherein the V-shaped blunt front edge is the V-shaped blunt front edge as claimed in any one of claims 1 to 3.