A strut flame stabilizer with a wavy cavity

Abstract

The present invention relates to a strut flame stabilizer with wavy cavities. The strut flame stabilizer is composed of a leading edge, a straight section, and a V-shaped bottom surface. Wavy cavities containing 3 to 5 wavelengths are arranged on both side surfaces of the straight section. The advantages and beneficial effects of the present invention are as follows: When the afterburner adopts the strut flame stabilizer with wavy cavities, it has good flame stabilization performance, high combustion efficiency, and small flow resistance loss.

Description

Technical Field

[0001] The present invention relates to a strut flame holder with wavy cavities, which can be used in an integrated afterburner of a high thrust-to-weight ratio aeroengine and belongs to the field of aviation technology. Background Art

[0002] The new generation of afterburning turbofan engines pursues a high thrust-to-weight ratio. In terms of the afterburner, it is required that the components are simple, the cold flow resistance loss is low, the proportion of the afterburning section length is small, and the afterburning efficiency is high at the same time. The afterburner uses a flame holder to stabilize the flame for combustion, and the performance of the flame holder is a decisive factor affecting the performance of the afterburner. Most of the new generation of afterburning turbofan engines adopt an integrated afterburner with an integrated design of a fairing strut and a flame holder. However, the conventional strut flame holder generates a von Kármán vortex street type recirculation vortex, and the stability of the recirculation vortex is poor, which will lead to locally unstable combustion.

[0003] Due to the small proportion of the afterburning section length, the distance from the fuel injection to the trailing edge of the flame holder becomes correspondingly smaller. Before being ignited, the fuel atomization, evaporation and mixing are not sufficient, which easily leads to unstable combustion. After superimposing with the unstable combustion caused by the recirculation vortex, the combustion instability problem will be amplified, thereby affecting the combustion reaction process; the distance from the trailing edge of the flame holder to the nozzle outlet becomes correspondingly smaller, the combustion section becomes shorter, and the flame in the recirculation zone behind the flame holder cannot spread across the entire combustion chamber transversely in time. Part of the oil-gas mixture is not fully burned, and part of the oil-gas mixture is directly discharged without participating in combustion, thus seriously affecting the afterburning efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a strut flame holder with wavy cavities, and wavy cavities are arranged on both side surfaces of the strut flame holder to improve the flame stability, reduce the flow loss and increase the combustion efficiency.

[0005] The present invention is realized through the following technical solutions.

[0006] A strut flame holder with wavy cavities, and wavy cavities are arranged on both side surfaces of the strut flame holder.

[0007] Furthermore, for the strut flame holder, the chord length is 90 - 150 mm, the span length is determined by the specific engine, and it consists of a leading edge, a straight section, and a V-shaped bottom surface. The leading edge is an elliptical surface, and the major axis dimension of the ellipse is 1.7 - 2.5 times that of the minor axis. The leading edge is tangent and continuous with the straight section. The width of the straight section is 24 - 36 mm, and the included angle of the V-shaped bottom surface is 100° - 150°.

[0008] Furthermore, the wavy geometric features of the wavy cavity include 3 to 5 wavelengths, starting and ending at the wave crest positions. The wavy shape is obtained by rounding the corners at the crests and troughs of the zigzag wave, with a fillet radius of 15 to 30 mm, the amplitude of the zigzag wave being 6 to 15 mm, the chordwise distance from the wave midline of the front wall of the wavy cavity to the trailing edge of the strut flame stabilizer being 30 to 36 mm, the cross-sectional shapes of all parts of the wavy cavity being the same, the cross-section being trapezoidal, the front wall of the wavy cavity being perpendicular to the bottom surface, the included angle between the rear wall and the bottom surface being 150° to 160°, the height of the front wall being 5 to 7 mm, and the width of the bottom surface being 10 to 12 mm.

[0009] Compared with the prior art, the advantages and beneficial effects achieved by the present invention are as follows:

[0010] First, the flame stabilization performance is good. The conventional strut flame stabilizer generates a von Kármán vortex street type recirculation vortex, and the stability of its recirculation vortex is poor, and combustion instability problems are likely to occur. After arranging wavy cavities on both sides of the conventional strut flame stabilizer, a K-H type recirculation vortex is generated, and the stability of the recirculation vortex is enhanced. The vortices in the cavities are beneficial to the evaporation and mixing of fuel, which is conducive to stable and efficient combustion. The wavy cavities form vortices, causing the mainstream near the wall surface to flow towards the rear wall of the cavity. The wavy geometric features of the cavities make the fuel more concentrated in the wake area of the troughs relative to the wake area of the crests, and the fuel content along the span of the flame stabilizer is distributed in a wavy shape, which is beneficial to broadening the flame stabilization range. Therefore, better flame stabilization performance can be obtained.

[0011] Second, the combustion efficiency is high. After arranging wavy cavities on both sides of the conventional strut flame stabilizer, a K-H type recirculation vortex is generated, and the stability of the recirculation vortex is enhanced. The vortices in the cavities are beneficial to the evaporation and mixing of fuel, and also cause the mainstream near the wall surface to flow towards the rear wall of the cavity. The wavy geometric features of the cavities make the fuel more concentrated in the wake area of the troughs relative to the wake area of the crests, and the fuel content along the span of the flame stabilizer is distributed in a wavy shape, which is beneficial to obtaining stable and efficient combustion. Therefore, higher combustion efficiency can be obtained.

[0012] Third, the flow resistance loss is small. To achieve the same flame stabilization performance and combustion efficiency, compared with increasing the blockage thickness of the conventional strut flame stabilizer, arranging wavy cavities on both sides of the conventional strut flame stabilizer causes less flow resistance loss. Moreover, replacing the von Kármán vortex street type recirculation vortex with a K-H type recirculation vortex is beneficial to reducing the flow resistance loss. Therefore, the flow resistance loss is smaller. Description of the Drawings

[0013] Figure 1 An isometric view of the strut flame stabilizer with wavy cavities in the present invention.

[0014] Figure 2 A side view of the strut flame stabilizer with wavy cavities in the present invention.

[0015] Figure 3 It is the top view of the strut flame stabilizer with a wavy cavity in the present invention.

[0016] Figure 4 It is the front view of the strut flame stabilizer with a wavy cavity in the present invention.

[0017] Figure 5 It is the rear view of the strut flame stabilizer with a wavy cavity in the present invention.

[0018] Figure 6 It is the longitudinal section V X distribution of the strut flame stabilizer with a wavy cavity in the present invention.

[0019] Figure 7 It is the transverse section V X distribution of the strut flame stabilizer with a wavy cavity in the present invention.

[0020] Figure 8 It is the streamline of the strut flame stabilizer with a wavy cavity in the present invention. Figure 1 。

[0021] Figure 9 It is the streamline of the strut flame stabilizer with a wavy cavity in the present invention. Figure 2 。

[0022] In the attached drawings, 1 is the leading edge; 2 is the straight section; 3 is the V-shaped bottom surface; 4 is the wavy cavity; L1 is the chord length of the strut flame stabilizer; L2 is the width of the bottom surface of the wavy cavity; L3 is the chordwise distance from the wave midline of the front wall of the wavy cavity to the trailing edge of the strut flame stabilizer; W1 is the width of the straight section; W2 is the height of the front wall of the wavy cavity; H1 is the span of the strut flame stabilizer; α1 is the included angle of the V-shaped bottom surface of the strut flame stabilizer; α2 is the included angle between the rear wall and the bottom surface of the wavy cavity; R is the fillet radius of the fillets at the wave peaks and wave troughs of the zigzag wave; A is the amplitude of the zigzag wave. Detailed implementation manners

[0023] Next, the present invention will be further described in detail in conjunction with the attached Figures 1 to 5 drawings and embodiments.

[0024] A strut flame stabilizer with a wavy cavity is provided with wavy cavities 4 on both side surfaces of the strut flame stabilizer.

[0025] As a further improvement of the embodiment of the present invention, for the strut flame stabilizer, the chord length L1 is 90 - 150 mm, specifically 120 mm in this embodiment; the span H1 is determined by the specific engine, specifically 180 mm in this embodiment. It is composed of a leading edge 1, a straight section 2, and a V-shaped bottom surface 3. The leading edge 1 is an elliptical surface, and the major axis dimension of the ellipse is 1.7 - 2.5 times the minor axis, specifically 1.77 times in this embodiment. The leading edge 1 is tangent and continuous with the straight section 2. The width W1 of the straight section 2 is 24 - 36 mm, specifically 26 mm in this embodiment. The included angle α1 of the V-shaped bottom surface 3 is 100° - 150°, specifically 120° in this embodiment.

[0026] As a further improvement of the embodiment of the present invention, the wavy geometric feature of the wavy cavity 4 includes 3 - 5 wavelengths, specifically 3 in this embodiment, starting and ending at the wave crest positions. The wavy shape is obtained by rounding the wave crests and wave troughs of a sawtooth wave, and the rounding radius R is 15 - 30 mm, specifically 18 mm in this embodiment. The amplitude A of the sawtooth wave is 6 - 15 mm, specifically 12 mm in this embodiment. The chordwise distance L3 from the wave midline of the front wall of the wavy cavity 4 to the trailing edge of the strut flame stabilizer is 30 - 36 mm, specifically 33 mm in this embodiment. The cross-sectional shape of each part of the wavy cavity 4 is the same, and the cross-section is trapezoidal. The front wall of the wavy cavity 4 is perpendicular to the bottom surface, the included angle α2 between the rear wall and the bottom surface is 150° - 160°, specifically 155° in this embodiment. The height W2 of the front wall is 5 - 7 mm, specifically 6 mm in this embodiment. The width L2 of the bottom surface is 10 - 12 mm, specifically 11 mm in this embodiment.

[0027] The above-described embodiments are only the preferred embodiments of the present invention, rather than an exhaustive list of all feasible embodiments of the present invention. For those of ordinary skill in the art, any obvious modifications made without departing from the principles and spirit of the present invention should be considered to be included within the protection scope of the claims of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the said claims.

Claims

1. A strut flame stabilizer with a wavy cavity, characterized in that, The described strut flame stabilizer has a chord length of 90 - 150 mm, and the span length is determined by the specific engine; the strut flame stabilizer is composed of a leading edge (1), a straight section (2), and a V-shaped bottom surface (3). The leading edge (1) is an elliptical surface, and the major axis dimension of the ellipse is 1.7 - 2.5 times that of the minor axis. The leading edge (1) is tangent and continuous with the straight section (2). The width of the straight section (2) is 24 - 36 mm. The included angle of the V-shaped bottom surface (3) is 100° - 150°. Wave-shaped cavities (4) are arranged on both side surfaces of the strut flame stabilizer. The wave shape of the wave-shaped cavity (4) contains 3 - 5 wavelengths, starting and ending at the wave crest positions. The wave shape is obtained by rounding the wave crest and wave trough of a sawtooth wave, with a rounding radius of 15 - 30 mm. The amplitude of the sawtooth wave is 6 - 15 mm. The chordwise distance from the wave midline of the front wall of the wave-shaped cavity (4) to the trailing edge of the strut flame stabilizer is 30 - 36 mm. The cross-sectional shape of each part of the wave-shaped cavity (4) is the same, and the cross-section is trapezoidal. The front wall of the wave-shaped cavity (4) is perpendicular to the bottom surface, and the included angle between the rear wall and the bottom surface is 150° - 160°. The height of the front wall is 5 - 7 mm, and the width of the bottom surface is 10 - 12 mm.

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