阅读说明：本技术 一种组合式燃烧稳定装置 (Combined combustion stabilizing device ) 是由 丁兆波 孙纪国 刘倩 杨进慧 许晓勇 于 2019-09-29 设计创作，主要内容包括：一种组合式燃烧稳定装置,包括喷注器基体、氧化剂顶盖、声腔环、隔板喷嘴和普通喷嘴；喷注器基体和氧化剂顶盖焊接连接,喷注器基体上表面为V型阶梯式结构,喷注器基体和氧化剂顶盖形成氧化剂头腔。声腔环焊接于喷注器基体下表面外缘,声腔环和喷注器基体之间形成燃料头腔。隔板喷嘴和喷注器基体V型阶梯式结构之间通过螺纹+钎焊的形式连接,且隔板喷嘴伸出喷注器基体下表面一定距离；在喷注器基体的V型阶梯式结构上,以V型阶梯式结构中心为圆心,安装有多圈普通喷嘴。本发明从源头上降低了高频不稳定燃烧的激励源,同时可以对多种振型的推力室固有声学不稳定和喷注耦合声学不稳定进行抑制。(A combined combustion stabilizing device comprises an injector substrate, an oxidant top cover, an acoustic cavity ring, a clapboard nozzle and a common nozzle; the injector substrate and the oxidant top cover are connected in a welding mode, the upper surface of the injector substrate is of a V-shaped stepped structure, and the injector substrate and the oxidant top cover form an oxidant head cavity. The acoustic cavity ring is welded on the outer edge of the lower surface of the injector substrate, and a fuel head cavity is formed between the acoustic cavity ring and the injector substrate. The clapboard nozzle and the injector matrix V-shaped stepped structure are connected in a thread and brazing mode, and the clapboard nozzle extends out of the lower surface of the injector matrix for a certain distance; a plurality of circles of common nozzles are arranged on the V-shaped stepped structure of the injector substrate by taking the center of the V-shaped stepped structure as the center of a circle. The invention reduces the excitation source of high-frequency unstable combustion from the source, and can inhibit the inherent acoustic instability and the injection coupling acoustic instability of the thrust chamber with various vibration modes.)

1. A combined combustion stabilizing device is characterized in that: the ultrasonic ejector comprises an ejector substrate (1), an oxidant top cover (2), an acoustic cavity ring (5), a partition plate nozzle and a common nozzle;

the injector base body (1) is welded and connected with the oxidant top cover (2), the upper surface of the injector base body (1) is of a V-shaped stepped structure, and the injector base body (1) and the oxidant top cover (2) form an oxidant head cavity (4);

the acoustic cavity ring (5) is welded on the outer edge of the lower surface of the injector base body (1), a fuel head cavity (3) is formed between the acoustic cavity ring (5) and the injector base body (1), and a fuel head cavity inlet (6) is machined in the lower surface of the injector base body (1);

the clapboard nozzle and the V-shaped stepped structure of the injector base body (1) are connected in a mode of thread and brazing, and the clapboard nozzle extends out of the lower surface of the injector base body (1) for a certain distance;

a plurality of circles of common nozzles are arranged on the V-shaped stepped structure of the injector substrate (1) by taking the center of the V-shaped stepped structure as the center of a circle.

2. The combined combustion stabilizing device of claim 1, wherein: the baffle nozzle adopts the following two arrangement modes:

1) the center of the V-shaped stepped structure is taken as the center of a circle and is circumferentially arranged along the radius r, and adjacent partition plate nozzles are closely adjacent to form a closed annular partition plate structure;

2) the partition plate nozzles form m strip-shaped arrays, each strip-shaped array is radially arranged along the V-shaped stepped structure, adjacent partition plate nozzles are closely adjacent, and the m strip-shaped arrays are uniformly distributed along the circumferential direction which takes the center of the V-shaped stepped structure as the center of a circle.

3. The combined combustion stabilizing device of claim 2, wherein: the side wall of the clapboard nozzle is provided with a radial inlet hole and a cooling channel, and the fuel in the fuel head cavity (3) enters from the inlet hole and is discharged after being cooled by the cooling channel.

4. The combined combustion stabilizing device of claim 1, wherein: in the multi-circle common nozzle, n1 circles positioned at the outermost part are low-flow-intensity-density nozzles, n2 circles positioned at the middle part are high-flow-intensity-density nozzles, and the other circles are reference-flow-intensity-density nozzles, wherein n1 is 1, 2 or 3, and n2 is 1 or 2.

5. The combined combustion stabilizing device of claim 4, wherein: the lengths of the common nozzles are different, and the common nozzles are gradually increased from the center of the V-shaped stepped structure outwards, so that the outlet of each nozzle is flush with the lower surface of the injector base body (1).

6. The combined combustion stabilizing device of claim 1, wherein: the edge of the sound cavity ring (5) is circumferentially provided with a plurality of independent sound cavities with different depths and opening widths, and two adjacent sound cavities are separated by a sound cavity separation rib (7).

7. The combined combustion stabilizing device of claim 1, wherein: an ignition channel is arranged at the central position of the injector base body (1), one end of the ignition channel penetrates through the oxidant top cover (2) to be connected with an external ignition source, and the other end of the ignition channel is communicated with a downstream combustion chamber.

8. A method of implementing a combined combustion stabilizing arrangement as claimed in any one of claims 1 to 7, characterized by the steps of:

(1) the oxidant of the oxidant head cavity (4) enters from the axial inlets of the common nozzle and the partition plate nozzle and is sprayed into a downstream combustion chamber;

(2) after flowing out from a regenerative cooling channel of the upstream combustion chamber, the fuel enters a fuel head cavity (3) through a fuel head cavity inlet (6) to cool an acoustic cavity ring (5);

(3) a part of the cooled fuel enters from a radial inlet of a common nozzle, is directly sprayed into a downstream combustion chamber and is mixed with an oxidant; the other part enters from a radial inlet of the clapboard nozzle, is discharged to a downstream combustion chamber after being cooled by the cooling channel and is mixed with an oxidant;

(4) an ignition source ignites the combustion agent and oxidant in the downstream combustion chamber through an ignition passageway.

Technical Field

The invention relates to a combined combustion stabilizing device, and belongs to the technical field of liquid rocket engines.

Background

The problem of unstable combustion is always a worldwide problem which troubles the technical development of the liquid rocket engine. In the development of almost every high thrust liquid rocket engine, unstable combustion problems are encountered, with high frequency unstable combustion being the most damaging, potentially leading to transient ablation or structural damage to engine components. High frequency combustion instabilities can generally be divided into two broad categories: inherent acoustic instability and injection-coupled acoustic instability. The inherent acoustic instability is caused by the coupling between the propellant combustion heat release process and the combustion chamber acoustic mode shape. Whereas the injection coupling acoustic instability is caused by the coupling between the propellant injection process and the combustion chamber acoustic mode.

In order to control the occurrence of combustion instability in engineering, measures can be taken from two aspects: firstly, according to the coupling mechanism, a targeted measure is adopted to weaken the coupling action of the oscillator so as to reduce the energy for maintaining oscillation; secondly, damping can be increased by adding a stable device such as a clapboard and the like, so that oscillation is promoted to be attenuated. Practice has shown that different stability measures are required for different types of combustion instabilities, and that, particularly with increasing engine thrust, a single stability measure for a certain unstable mode shape has traditionally not been able to solve the problem.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the defects of the prior art are overcome, and the combined combustion stabilizing device is provided, so that the excitation source of high-frequency unstable combustion is reduced from the source, and the inherent acoustic instability and the injection coupling acoustic instability of the thrust chamber with various vibration modes can be inhibited.

The technical solution of the invention is as follows:

a combined combustion stabilizing device comprises an injector substrate, an oxidant top cover, an acoustic cavity ring, a clapboard nozzle and a common nozzle;

the injector substrate and the oxidant top cover are welded and connected, the upper surface of the injector substrate is of a V-shaped stepped structure, and the injector substrate and the oxidant top cover form an oxidant head cavity;

the acoustic cavity ring is welded on the outer edge of the lower surface of the injector substrate, a fuel head cavity is formed between the acoustic cavity ring and the injector substrate, and a fuel head cavity inlet is machined in the lower surface of the injector substrate;

the clapboard nozzle and the injector matrix V-shaped stepped structure are connected in a thread and brazing mode, and the clapboard nozzle extends out of the lower surface of the injector matrix for a certain distance;

a plurality of circles of common nozzles are arranged on the V-shaped stepped structure of the injector substrate by taking the center of the V-shaped stepped structure as the center of a circle.

The baffle nozzle adopts the following two arrangement modes:

1) the center of the V-shaped stepped structure is taken as the center of a circle and is circumferentially arranged along the radius r, and adjacent partition plate nozzles are closely adjacent to form a closed annular partition plate structure;

2) the partition plate nozzles form m strip-shaped arrays, each strip-shaped array is radially arranged along the V-shaped stepped structure, adjacent partition plate nozzles are closely adjacent, and the m strip-shaped arrays are uniformly distributed along the circumferential direction which takes the center of the V-shaped stepped structure as the center of a circle.

The side wall of the clapboard nozzle is provided with a radial inlet hole and a cooling channel, and the fuel in the fuel head cavity enters from the inlet hole and is discharged after being cooled by the cooling channel.

In the multi-circle common nozzle, n1 circles positioned at the outermost part are low-flow-intensity-density nozzles, n2 circles positioned at the middle part are high-flow-intensity-density nozzles, and the other circles are reference-flow-intensity-density nozzles, wherein n1 is 1, 2 or 3, and n2 is 1 or 2.

The lengths of the common nozzles are different, and the common nozzles are gradually increased outwards from the center of the V-shaped stepped structure, so that the outlet of the nozzle is flush with the lower surface of the injector substrate.

The edge circumference of the sound cavity ring is provided with a plurality of independent sound cavities with different depths and opening widths, and two adjacent sound cavities are separated by a sound cavity partition rib.

An ignition channel is arranged at the central position of the injector substrate, one end of the ignition channel penetrates through the oxidant top cover to be connected with an external ignition source, and the other end of the ignition channel is communicated with a downstream combustion chamber.

The implementation method of the combined combustion stabilizing device comprises the following steps:

(1) the oxidant of the oxidant head cavity enters from the axial inlets of the common nozzle and the partition plate nozzle and is sprayed into a downstream combustion chamber;

(2) after flowing out from the upstream combustion chamber regenerative cooling channel, the fuel enters the fuel head cavity through the inlet of the fuel head cavity to cool the acoustic cavity ring;

(3) a part of the cooled fuel enters from a radial inlet of a common nozzle, is directly sprayed into a downstream combustion chamber and is mixed with an oxidant; the other part enters from a radial inlet of the clapboard nozzle, is discharged to a downstream combustion chamber after being cooled by the cooling channel and is mixed with an oxidant;

(4) an ignition source ignites the combustion agent and oxidant in the downstream combustion chamber through an ignition passageway.

Compared with the prior art, the invention has the beneficial effects that:

(1) the injector substrate adopts a stepped design, so that the length of each circle of oxidant nozzles (common nozzles) can be changed, the frequency of the oxidant nozzles is obviously increased along with the reduction of the length of the nozzles, on one hand, the energy required by exciting coupling resonance is greatly increased, on the other hand, the longitudinal acoustic frequency inconsistency and energy dispersion of each circle of oxidant nozzles are ensured, the acoustic frequency error is realized, and the occurrence of unstable injection coupling acoustics is greatly inhibited.

(2) The common nozzle adopts a flow intensity density partition design, so that the concentration of combustion energy release can be effectively reduced, and the excitation source of high-frequency unstable combustion can be effectively reduced by reducing the flow intensity density of the transverse vibration mode pressure wave trough.

(3) The invention adopts the design of the radial/circumferential combined discharge type clapboard nozzle, and can effectively damp typical transverse unstable vibration modes.

(4) The invention adopts the design of the composite acoustic cavity, can be used as effective supplement of the partition board by adjusting the depth of the acoustic cavity, adjusts the suppressed frequency of the partition board, and can correspondingly adjust the damping characteristic of the partition board by adjusting the width of the acoustic cavity.

Drawings

FIG. 1 is a schematic view of the combined combustion stabilizing device of the present invention;

FIG. 2 is a view from the A direction of the schematic structural diagram of the combined combustion stabilizing device of the present invention;

FIG. 3 is a schematic diagram of the structure of the acoustic chamber of the modular combustion stabilization unit of the present invention, wherein (a) is a top view and (b) is a cross-sectional view.

Detailed Description

The combined combustion stabilizing device achieves the purpose that the combined combustion stabilizing device can simultaneously restrain inherent acoustic instability and injection coupling acoustic instability of thrust chambers with various vibration modes.

Specifically, the combined combustion stabilizing device provided by the invention comprises an injector base body 1, an oxidant top cover 2, an acoustic cavity ring 5, a common nozzle and a diaphragm nozzle, as shown in figure 1.

The injector base body 1 is welded and connected with the oxidant top cover 2, the upper surface of the injector base body 1 is of a V-shaped stepped structure, an ignition channel is arranged at the central position of the injector base body 1, one end of the ignition channel penetrates through the oxidant top cover 2 to be connected with an external ignition source, and the other end of the ignition channel is communicated with a downstream combustion chamber; the injector base body 1 and the oxidant cap 2 form an oxidant head chamber 4.

The acoustic cavity ring 5 is welded on the outer edge of the lower surface of the injector base body 1, a fuel head cavity 3 is formed between the acoustic cavity ring 5 and the injector base body 1, and a fuel head cavity inlet 6 is machined in the lower surface of the injector base body 1. The combustor regeneration coolant enters the fuel head chamber 3 through the fuel head chamber inlet 6 while cooling the acoustic chamber ring 5.

The clapboard nozzle and the injector matrix 1V-shaped stepped structure are connected through threads and brazing and extend out of the lower surface of the injector matrix 1 for a certain distance. The side wall of the clapboard nozzle is provided with a radial inlet hole and a cooling channel, and the fuel in the fuel head cavity 3 enters from the inlet hole and is discharged after being cooled by the cooling channel.

As shown in FIG. 2, diaphragm nozzles including a combined discharge design employing radial diaphragm nozzles 11 and circumferential diaphragm nozzles 12 may effectively damp typical laterally unstable modes. The circumferential partition plate nozzles 12 are circumferentially arranged along the radius r by taking the center of the V-shaped stepped structure as the circle center, and adjacent partition plate nozzles are closely adjacent to form a closed annular partition plate structure; the radial baffle nozzles 11 form m strip-shaped arrays, each strip-shaped array is arranged along the radial direction, adjacent baffle nozzles are closely adjacent, and the m strip-shaped arrays are uniformly distributed along the circumferential direction which takes the center of the V-shaped stepped structure as the center of a circle.

On the V-shaped stepped structure of the injector substrate 1, a plurality of circles of ordinary nozzles are installed by taking the center of the V-shaped stepped structure as the center of a circle, wherein n1 circles positioned at the outermost part are low-flow high-density nozzles, n2 circles positioned at the middle part are high-flow high-density nozzles, and the other circles are reference-flow high-density nozzles. n1 is 1, 2 or 3, and n2 is 1 or 2.

As shown in fig. 2, the outermost 2 rings were formed by using the # 1 low flow intensity nozzle 15 and the # 2 low flow intensity nozzle 16 as the low flow intensity nozzles. The middle 4 circles are high-flow-intensity nozzles formed by using 1# high-flow-intensity nozzles 13 and 2# high-flow-intensity nozzles 14. The other rings are formed by using the reference flow high density nozzles 17 as the reference flow high density nozzles. The types of the inner nozzles in the same circle are consistent. The partition design of the flow intensity of the common nozzle can effectively reduce the concentration of combustion energy release on one hand, and can effectively reduce the excitation source of high-frequency unstable combustion by reducing the flow intensity of the transverse vibration type pressure wave trough on the other hand.

The lengths of the common nozzles are different, and the common nozzles are gradually increased from the center of the V-shaped stepped structure outwards, so that the outlet of each nozzle is flush with the lower surface of the injector substrate 1.

As shown in fig. 2, a composite acoustic cavity design is adopted in the circumferential direction of the injector substrate 1, and the acoustic cavities 8 # 1, 9 # 2 and 10 # 3 with different depths and opening areas are arranged at intervals and can be used as effective supplements of the partition plate to damp the frequencies or higher-order frequencies in the partition plate regions with different frequencies.

As shown in fig. 3, a plurality of independent acoustic cavities with different depths h and opening widths b are circumferentially arranged at the edge of the acoustic cavity ring 5, and two adjacent acoustic cavities are separated by an acoustic cavity barrier rib 7. The suppression frequency can be correspondingly adjusted by adjusting the depth h of the acoustic cavity; by adjusting the width b of the acoustic cavity, the damping characteristics can be adjusted accordingly. In fig. 3, (a) is a plan view and (b) is a sectional view.

The combined combustion stabilizing device of the invention is realized by the following method:

(1) the oxidant of the oxidant head cavity 4 enters from the axial inlets of the common nozzle and the partition nozzle and is sprayed into a downstream combustion chamber;

(2) after flowing out from the upstream combustion chamber regenerative cooling channel, the fuel enters the fuel head cavity 3 through the fuel head cavity inlet 6 to cool the acoustic cavity ring 5;

(3) a part of the cooled fuel enters from a radial inlet of a common nozzle, is directly sprayed into a downstream combustion chamber and is mixed with an oxidant; the other part enters from a radial inlet of the clapboard nozzle, is discharged to a downstream combustion chamber after being cooled by the cooling channel and is mixed with an oxidant;

(4) an ignition source ignites the combustion agent and oxidant in the downstream combustion chamber through an ignition passageway.

The invention comprises a stepped injector, a flow intensity partition, a discharge type partition nozzle and a composite sound cavity, on one hand, the excitation source of high-frequency unstable combustion is reduced from the source, on the other hand, the unstable frequency error of injection coupling acoustics can be realized, and the effective inhibition of the high-frequency unstable combustion of inherent acoustics of various vibration modes can be realized.

The invention is not described in detail and is within the knowledge of a person skilled in the art.