Injection structure for a rotating detonation combustion chamber to suppress pressure back transmission, rotating detonation turbine engine

Abstract

The present application relates to air-breathing rotary detonation turbine engine technical field, specifically to a kind of rotary detonation combustion chamber injection structure for inhibiting pressure back transmission, comprising: combustion chamber, combustion chamber is cylindrical structure;Laval injection channel, set in one end of combustion chamber, Laval injection channel includes multiple grooves, groove is inclined to the axis of combustion chamber Setting;Air injection cavity, set in one end of Laval injection channel away from combustion chamber;Storage channel, interval setting with the inner wall of combustion chamber, fuel is arranged in storage channel, and multiple fuel injection holes are arranged between storage channel and combustion chamber. By setting Laval injection channel in one end of combustion chamber, while, groove is inclined to the axis of combustion chamber Setting;Injection structure can reduce the situation of pressure oscillation propagating upstream to some extent, the injection structure is inclined along the detonation wave propagation direction Control pressure back transmission effect is more obvious, and flow field stability is obviously enhanced.

Description

Technical Field

[0001] This invention relates to the field of air-breathing rotary detonation turbine engine technology, specifically to a rotary detonation combustion chamber injection structure for suppressing pressure back transmission and a rotary detonation turbine engine. Background Technology

[0002] Traditional air-breathing aero-engines mostly employ isobaric combustion based on the Brayton cycle. However, with advancements in technology and engineering, the cycle efficiency of this method has gradually reached its limit, making further significant improvements difficult. Detonation combustion, as a quasi-isochoric combustion method, features rapid heat release and self-pressurization, theoretically offering higher cycle efficiency and lower pollutant emissions. In combustion chambers employing detonation combustion, the rotating detonation combustor has a simple structure and requires only a single detonation for long-term stable operation, potentially leading to a leap forward in the aero-engine field.

[0003] The rotary detonation combustor ignites the axially injected fuel-oxidant mixture through one or more detonation waves that continuously rotate and propagate in the circumferential direction, thus achieving a pressurization effect. The detonation wave can be regarded as a strongly coupled wave of chemical reaction and shock wave. The coupled detonation wave can circulate and propagate at speeds of thousands of meters per second in the combustion chamber in a direction perpendicular to the fuel injection, continuously burning the injected mixture. This combustion method significantly improves the combustion rate, enabling the combustion chamber to operate stably over a fairly wide range of incoming flow velocities and shortening the residence time in the combustion chamber, thereby reducing the generation and emission of pollutants such as NOx.

[0004] However, the rotating detonation wave inevitably causes pressure oscillations upstream and downstream, especially pressure back transmission upstream. This problem must be solved when applying detonation combustors to air-breathing engines. As is well known, the stable operating conditions of compressors are quite demanding. Even minor disturbances can lead to flow separation, reduced efficiency, or even surge. The efficiency of the compressor has a significant impact on the cycle efficiency of aero-engines. When the compressor efficiency is low, the efficiency of a rotating detonation turbine engine may even be lower than that of a conventional turbine engine. On the other hand, the high-frequency rotating tail shock wave propagating upstream will inevitably affect the stability and service life of the engine. Therefore, controlling and reducing pressure back transmission is imperative in the matching of detonation combustors with air-breathing engines.

[0005] Therefore, some scholars have attempted to control pressure back transmission by redesigning isolation sections and isolation structures, while others have tried to reduce it through injection structures. However, there are few studies on flow matching that take into account flow losses. Summary of the Invention

[0006] Therefore, the present invention provides a rotary detonation combustion chamber injection structure for suppressing pressure back transmission and a rotary detonation turbine engine.

[0007] To address the aforementioned technical problems, this invention provides a rotary detonation combustion chamber injection structure for suppressing pressure back transmission, comprising: a combustion chamber, the combustion chamber being a cylindrical structure; a Laval injection channel located at one end of the combustion chamber, the Laval injection channel comprising multiple grooves, the grooves being inclined to the axis of the combustion chamber; an air injection chamber located at the end of the Laval injection channel away from the combustion chamber; and a storage channel spaced apart from the inner wall of the combustion chamber, the storage channel containing fuel, and multiple fuel injection holes being provided between the storage channel and the combustion chamber.

[0008] Furthermore, the angle between the groove and the axis of the combustion chamber is 10°-40°.

[0009] Furthermore, the angle between the groove and the axis of the combustion chamber is 15°.

[0010] Furthermore, the angle between the groove and the axis of the combustion chamber is 30°.

[0011] Furthermore, the throat width of the Laval injection channel is 0.5 mm, and the inlet width is 1.5 mm.

[0012] Furthermore, it also includes a grille, which is inserted into the groove.

[0013] The present invention also provides a rotary detonation turbine engine, including the aforementioned rotary detonation combustion chamber injection structure for suppressing pressure back transmission.

[0014] Furthermore, it also includes: a compressor outlet guide vane, the outlet guide vane being located at the end of the air injection chamber away from the combustion chamber.

[0015] Furthermore, it also includes: a supersonic turbine is provided at the end of the combustion chamber away from the compressor outlet guide vane.

[0016] The technical solution of this invention has the following advantages: The present invention provides a rotary detonation combustion chamber injection structure for suppressing pressure back transmission, comprising: a combustion chamber, wherein the combustion chamber is a cylindrical structure; a Laval injection channel disposed at one end of the combustion chamber, the Laval injection channel comprising multiple grooves, the grooves being inclined to the axis of the combustion chamber; an air injection chamber disposed at the end of the Laval injection channel away from the combustion chamber; and a storage channel spaced apart from the inner wall of the combustion chamber, wherein fuel is disposed in the storage channel, and multiple fuel injection holes are provided between the storage channel and the combustion chamber.

[0017] By setting a Laval injection channel at one end of the combustion chamber, and the injection channel comprising multiple grooves inclined to the axis of the combustion chamber, the injection structure can reduce the upstream propagation of pressure oscillations to a certain extent. The injection structure inclined along the direction of detonation wave propagation has a more significant effect on controlling pressure back propagation and significantly enhances flow field stability. For detailed results, please refer to the invention effects.

[0018] Specifically, the combustion chamber primarily relies on the rotating and propagating detonation wave within the chamber to continuously ignite the injected unburned fresh premixed gas. This detonation wave carries with it oblique shock waves from the downstream outlet and upstream reverse-propagating trailing shock waves. The rotating propagation of these trailing shock waves causes periodic pressure oscillations in upstream components, affecting their normal operation. Therefore, it is necessary to control and reduce the upstream propagation of these waves or pressure oscillations. Laval injection channels can reduce the upstream propagation of pressure oscillations to a certain extent. Laval injection structures inclined along the direction of detonation wave propagation show a more significant effect in controlling pressure reverse propagation and exhibit significantly enhanced flow field stability.

[0019] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or necessary features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the rotary detonation combustion chamber injection structure for suppressing pressure back transmission provided by the present invention; Figure 2 A perspective view of the rotary detonation combustion chamber injection structure for suppressing pressure back transmission provided by the present invention; Figure 3 A cross-sectional view of the rotary detonation combustion chamber injection structure for suppressing pressure back transmission provided by the present invention; Figure 4 A two-dimensional planar structural diagram of the tank body of the rotary detonation combustion chamber injection structure for suppressing pressure back transmission provided by the present invention; Figure 5 A schematic diagram of the injection channel for the rotary detonation combustion chamber injection structure for suppressing pressure back transmission provided by the present invention; Figure 6To compare the pressure oscillation within the injection chamber under the same total injection pressure; where point 1 is located at the contact plane between the injection structure and the injection chamber, and point 2 is located 5 mm upstream of it; Figure 7 A three-dimensional curve showing the reduction of pressure oscillations; Figure 8 This is a schematic diagram illustrating the differences in flow field stability.

[0022] Explanation of reference numerals in the attached figures: 1. Combustion chamber; 2. Laval injection channel; 3. Tank; 4. Air injection chamber; 5. Storage channel; 6. Fuel injection port; 7. Grille; 8. Compressor outlet guide vane; 9. Supersonic turbine. Detailed Implementation

[0023] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are to be considered exemplary in nature and not restrictive.

[0024] In the description of this disclosure, 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," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or connections that allow for communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0026] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] The following disclosure provides numerous different embodiments or examples for implementing various structures of this disclosure. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this disclosure. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this disclosure, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0028] The preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0029] Please see Figures 1 to 8 As shown, the present invention provides a rotary detonation combustion chamber injection structure for suppressing pressure back transmission, comprising: a combustion chamber 1, the combustion chamber 1 being a cylindrical structure; a Laval injection channel 2, disposed at one end of the combustion chamber 1, the Laval injection channel 2 including multiple grooves 3, the grooves 3 being inclined to the axis of the combustion chamber 1; an air injection chamber 4, disposed at the end of the Laval injection channel 2 away from the combustion chamber 1; and a storage channel 5, spaced apart from the inner wall of the combustion chamber 1, the storage channel 5 containing fuel, and multiple fuel injection holes 6 being provided between the storage channel 5 and the combustion chamber 1.

[0030] By setting a Laval injection channel 2 at one end of the combustion chamber 1, and the injection channel including multiple grooves 3, the grooves 3 being inclined to the axis of the combustion chamber 1, the injection structure can reduce the upstream propagation of pressure oscillations to a certain extent. That is, the injection structure with grooves 3 inclined along the direction of detonation wave propagation has a more obvious effect in controlling the back pressure transmission, and the flow field stability is significantly enhanced.

[0031] Specifically, combustion chamber 1 mainly relies on the detonation wave propagating in combustion chamber 1 to continuously ignite the injected unburned fresh premixed gas. The detonation wave will be accompanied by the oblique shock wave at the downstream outlet and the upstream reverse-propagating tail shock wave. The rotational propagation of the tail shock wave will cause periodic pressure oscillations in the upstream components, affecting the normal operation of the upstream components. Therefore, it is necessary to control and reduce the upstream propagation of this wave or pressure oscillation.

[0032] The Laval injection channel 2 can reduce the upstream propagation of pressure oscillations to a certain extent. The Laval injection channel 2, which is inclined along the direction of detonation wave propagation, has a more obvious effect on controlling the back pressure transmission and significantly enhances the stability of the flow field.

[0033] Air is injected through the trough 3 of the circumferential injection channel, while fuel is injected through 60 circumferentially distributed fuel injection holes 6. The two are mixed in the Laval injection channel 2.

[0034] The angle between the axis of the tank 3 and the axis of the combustion chamber 1 is 10°-40°.

[0035] In this embodiment, the angle between the axis of the groove 3 and the axis of the combustion chamber 1 is 15°. Of course, the angle between the axis of the groove 3 and the axis of the combustion chamber 1 can also be 30°.

[0036] This rotating detonation combustion chamber injection structure, which suppresses pressure back transmission, provides upstream components such as the compressor with the smoothest possible operating conditions, thereby improving efficiency and service life. Considering that fuel and air are mostly injected through small holes or channels 3, the shapes of both conventional injection structures and the injection structure of this invention are shown in two-dimensional planar diagrams.

[0037] See Figure 5 As shown, (a) is a traditional orifice-wide slot type, (b) is a traditional orifice-narrow slot type, (c) is a Laval injection channel, (d) is a Laval injection channel with a channel body tilted at 15°, and (e) is a Laval injection channel with a channel body tilted at 15°. Within the Laval injection channel 2, the throat width between two adjacent channels 3 is 0.5 mm, and the inflow width is 1.5 mm. To facilitate comparison of pressure oscillation reduction, the effects of conventional orifice-type injection systems were considered. Figure 5 (a), (b), where Figure 5 (a) The situation has the same injection area as the designed Laval injection channel. Figure 5 (b) The case has the same minimum area as the Laval injection channel and similar injection flow rate under the same injection conditions (e.g., total pressure).

[0038] Basic simulation calculations were performed on the above injection structure. The results show that compared with the traditional slot injection structure, the designed injection structure can reduce the upstream propagation of pressure oscillations to a certain extent. The Laval injection channel 2, which is inclined along the direction of detonation wave propagation, has a more obvious effect on controlling the back pressure transmission, and the flow field stability is significantly enhanced.

[0039] The specific content is described as follows: The injection structure of the present invention can be applied to an air-breathing rotary detonation turbine engine. The injection structure can be connected to the injection chamber of fuel and oxidizer at the top and the rotary detonation combustion chamber 1 at the bottom. The detonation wave rotates and propagates in the injection chamber, with a trailing shock wave constantly sweeping across the injection structure. Under the pressure boosting effect of the compressor, the total injection pressure can maintain most of the Laval injection channel 2 in a supersonic form, while the pressure disturbance cannot cross the supersonic region to propagate upstream. For a small part of the area behind the detonation wave, the Laval injection channel 2 is blocked by the extremely high pressure area behind the wave. In this part of the area, through the interaction between the tapering of the Laval injection channel 2 (for the anti-propagation wave) and the anti-propagation wave, that is, the anti-propagation wave will form a reflected wave when it hits the tapering wall to further reduce the airflow movement and pressure disturbance behind, thereby minimizing the upstream propagation of pressure oscillation.

[0040] Considering that the propagation of the detonation wave will cause some of the airflow behind the wave to propagate a certain distance along the direction of the detonation wave, and this motion will inevitably affect the motion of the reverse propagation wave, the airflow may be used to suppress the reverse wave. In addition, the wave reflection of the inclined Laval injection channel 2 is different from that of the vertical injection. Therefore, we designed the inclined Laval injection channel 2, that is, the vertical Laval injection channel 2 is inclined at 15° and 30° respectively along the direction of detonation wave propagation.

[0041] Since air-breathing engines primarily rely on air injection, it is crucial to minimize pressure backflow. Therefore, Laval injection channel 2 is selected for the air injection passage. To simplify the structure and ensure smooth flow, an annular groove injection is chosen. For fuel injection, where pressure oscillation is less critical, a traditional orifice injection is employed. The two types of fuel are cross-mixed in the expansion section of Laval injection channel 2 to enhance the mixing effect and prevent backfire.

[0042] Considering that most rotary detonation combustion chambers currently use hydrogen as fuel, it is necessary to take targeted measures to prevent hydrogen embrittlement during material selection and processing. This can be achieved by using new hydrogen-resistant steels, adding appropriate alloying elements to reduce the tendency for hydrogen embrittlement, and, if necessary, coating the exterior of the components with a protective layer.

[0043] See Figure 6 As shown, this injection structure, while maintaining simplicity and stability, significantly reduces the back-transmission amplitude of pressure oscillations compared to traditional slot injection structures. Taking a two-dimensional case as an example, as... Figure 6 As shown, for the same injection area ratio Figure 6(a) and Figure 6 (c) The injection structure significantly reduces pressure back transmission, but the flow rates differ greatly between the two cases, making the comparison not very valuable; for approximately the same flow rate... Figure 6 (b) and Figure 6 (c) The injection structure exhibits significant pressure oscillation suppression at point 2, 5 mm upstream of the plane where it contacts the injection chamber. Furthermore, the inclined Laval injection... Figure 6 (d) and Figure 6 (e) shows that the pressure oscillation almost disappears after the flow field stabilizes, indicating that the control and reduction effect of this structure is more obvious.

[0044] in, Figure 6 To compare the pressure oscillation within the injection chamber under the same total injection pressure; where point 1 is located at the contact plane between the injection structure and the injection chamber, and point 2 is located 5 mm upstream of it; Please see Figure 7 As shown, to closely approximate real-world applications, three-dimensional simulations were performed to further verify the structure's oscillation reduction capability. The results show that the pressure oscillation amplitude at the upstream monitoring point of the channel was reduced by 91%, confirming the structure's effectiveness. Furthermore, the injection structure enhances flow field stability. At lower flow rates, orifice-type injection systems cannot form stable detonation waves, operating in a quasi-detonation manner. However, due to its larger injection area ratio, the injection structure facilitates detonation wave formation, further improving the flow field stability of Laval injection channel 2.

[0045] The rotary detonation combustion chamber injection structure for suppressing pressure back-transmission also includes a grille 7, which is inserted into the channel 3. Arranging the grille 7 and inserting it into the channel 3 ensures that the airflow is incident at the required tilt angle, while simultaneously providing conditions for the reflection of back-transmission waves.

[0046] Of course, the grating 7 can also be a leaf grating.

[0047] The present invention also provides a rotary detonation turbine engine, including a rotary detonation combustion chamber injection structure for suppressing pressure back transmission, and further including a compressor outlet guide vane 8 and a supersonic turbine 9. The outlet guide vane 8 is located in front of the air injection chamber 4, and the supersonic turbine 9 is located at the end of the combustion chamber 1 away from the outlet guide vane 8.

[0048] Considering the application of the rotating detonation combustion chamber 1 in an air-breathing engine, the compressor 8, supersonic turbine 9 and rotating detonation combustion chamber 1 are integrated. The back transmission of control pressure oscillations to upstream components such as the compressor is reduced by using the Laval injection channel 2. At the same time, the airflow direction is adjusted by using the compressor outlet guide vane 7 so that it is injected at an angle along the direction of detonation wave propagation.

[0049] The main possible reasons for the reduction of back propagation by the injection structure are as follows: First, the circumferential velocity brought about by the inclined injection of the airflow along the direction of detonation wave propagation reduces the pressure oscillation; second, the reflection is more intense when the back propagation wave propagates along the inclined Laval channel.

[0050] Therefore, as Figure 1 As shown, the airflow direction is adjusted by the compressor outlet guide vane 8, causing the airflow to deflect about 15° in the direction of detonation wave propagation. Furthermore, blades or grids are inserted into the tank 3 to ensure that the airflow is incident at the required tilt angle, while providing conditions for the reflection of the back-transmitting wave. This scheme can comprehensively consider both the airflow direction and wave reflection mechanisms. It should be noted that the number of tanks 3 should correspond to the number of fuel injection holes 6 to ensure the mixing effect.

[0051] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A rotary detonation combustion chamber injection structure for suppressing pressure back transmission, characterized in that, include: Combustion chamber (1), wherein the combustion chamber (1) has a cylindrical structure; A circumferential Laval injection channel (2) is provided at one end of the combustion chamber (1). The Laval injection channel (2) includes multiple grooves (3). The grooves (3) and the axis of the combustion chamber (1) are inclined along the direction of detonation wave propagation. An air injection chamber (4) is located at one end of the Laval injection channel (2) away from the combustion chamber (1); A storage channel (5) is provided at a distance from the inner wall of the combustion chamber (1). Fuel is provided in the storage channel (5), and multiple fuel injection holes (6) are provided between the storage channel (5) and the combustion chamber (1). The angle between the axis of the tank (3) and the axis of the combustion chamber (1) is 10°-40°; It also includes a grille (7) inserted into the groove (3).

2. The rotary detonation combustion chamber injection structure for suppressing pressure back transmission according to claim 1, characterized in that, The angle between the axis of the tank (3) and the axis of the combustion chamber (1) is 15°.

3. The rotary detonation combustion chamber injection structure for suppressing pressure back transmission according to claim 1, characterized in that, The angle between the axis of the tank (3) and the axis of the combustion chamber (1) is 30°.

4. The rotary detonation combustion chamber injection structure for suppressing pressure back transmission according to claim 1, characterized in that, The throat width between two adjacent tanks (3) of the Laval injection channel (2) is 0.5 mm, and the inflow width is 1.5 mm.

5. A rotary detonation turbine engine, characterized in that, The rotary detonation combustion chamber injection structure for suppressing pressure back transmission, as described in any one of claims 1-4.

6. The rotary detonation turbine engine according to claim 5, characterized in that, Also includes: The compressor outlet guide vane (8) is located at the end of the air injection chamber (4) away from the combustion chamber (1).

7. The rotary detonation turbine engine according to claim 6, characterized in that, Also includes: A supersonic turbine (9) is provided at one end of the combustion chamber (1) away from the compressor outlet guide vane (8).

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