A multi-tube spiral sector impulse detonation combustion chamber

Abstract

This invention proposes a multi-tube spiral fan-shaped pulse detonation combustion chamber for a pulse detonation turbine engine, comprising a diffuser, a multi-tube spiral fan-shaped detonation tube, a fuel supply pipe, an outer casing for the combustion chamber, an inner casing for the combustion chamber, and an outlet pressure stabilizing chamber. The airflow, after passing through the diffuser, is divided into two parts. One part flows from the intake cone at the head of the spiral fan-shaped detonation tube into the fuel supply mixing section, where it mixes with fuel injected from the nozzle of the fuel supply mixing section. The combustible mixture enters the ignition and detonation section and is ignited by a hot jet igniter, forming a detonation wave after undergoing a deflagration-to-detonation process. The other part flows through the outer wall of the detonation tube, cooling the tube. The two airflows are mixed and pressure-stabilized in the outlet pressure stabilizing chamber before being discharged into the turbine. By employing a spiral fan-shaped detonation tube, on the one hand, the pulse detonation combustion chamber can be perfectly matched with the annular airflow channel at the compressor outlet of the gas turbine engine, improving the cross-sectional utilization of the flow channel and thus increasing the thrust of the pulse detonation turbine engine; on the other hand, the axial length of the pulse detonation combustion chamber can be shortened, thereby shortening the overall length of the pulse detonation turbine engine, reducing the total engine weight, improving the engine thrust-to-weight ratio, and improving the engine rotor dynamics characteristics due to the shortened axial distance of the entire rotor system.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, specifically a multi-tube spiral fan-shaped pulse detonation combustion chamber. Background Technology

[0002] The pulse detonation turbine engine is a new type of engine that replaces the isobaric combustion chamber of a traditional turbine engine with a pulse detonation combustion chamber. Currently, pulse detonation turbine engines can be classified into several types, including pulse detonation turbofan engines, pulse detonation turbojet engines, and pulse detonation turboshaft engines. Compared with traditional aero engines, it has advantages such as high thermal cycle efficiency, wide operating range, and superior performance per unit area, and has broad application prospects.

[0003] In practical applications, triggering detonation waves in large-diameter circular tubes is quite difficult. Therefore, pulse detonation turbine engines employing multi-tube pulse detonation combustor combinations are a trend in PDTE engineering applications. Currently, most multi-tube pulse detonation combustors consist of several circular cross-section detonation tubes, resulting in low actual cross-sectional utilization of the engine's annular airflow passage (cross-sectional utilization is defined as the ratio of the detonation chamber inlet cross-sectional area to the engine's annular airflow passage cross-sectional area), which is detrimental to improving engine thrust.

[0004] In practical applications, direct detonation of combustible mixtures requires a large amount of energy, and for multiphase non-homogeneous mixtures, direct detonation is very difficult. Indirect detonation is closer to practical engineering applications. Currently, one of the most promising detonation methods is the deflagration-to-detonation method. However, this method requires a long deflagration-to-detonation distance to generate the detonation wave, resulting in an excessively long axial distance in the pulse detonation combustion chamber and an excessively long axial length of the entire engine rotor system. The dynamics of the rotor system and the weight of the engine will limit the engineering application of pulse detonation turbo engines. Summary of the Invention

[0005] Technical problems to be solved

[0006] To improve the cross-sectional utilization of the pulse detonation combustor in the engine's annular flow channel and shorten the axial distance of the pulse detonation combustor, this invention provides a multi-tube spiral fan-shaped pulse detonation combustor. By circumferentially arranging several spiral fan-shaped detonation tubes with fan-shaped cross-sections in parallel, the cross-sectional utilization is improved, and the axial distance of the pulse detonation combustor is shortened, thereby increasing engine thrust, reducing engine mass, improving thrust-to-weight ratio, and improving engine rotor dynamics.

[0007] Technical solution

[0008] This invention provides a multi-tube spiral fan-shaped pulse detonation combustion chamber, comprising a diffuser 1, a fuel supply pipe 3, a multi-tube spiral fan-shaped detonation tube, an outer combustion chamber casing 7, an inner combustion chamber casing 8, and an outlet pressure stabilizing chamber 9; multiple spiral fan-shaped detonation tubes 6 are arranged in parallel along the circumference within the annular cavity formed by the outer combustion chamber casing 7 and the inner combustion chamber casing 8, and each spiral fan-shaped detonation tube consists of a fuel supply mixing section and an ignition and detonation section; the inlet of the fuel supply mixing section is provided with a head intake cone 2, and a fuel nozzle 4 is installed at the center of the leeward side of the head intake cone 2; the fuel supply pipe passes through the outer casing of the outer combustion chamber casing and the spiral fan-shaped detonation tube, extends into the head intake cone, and communicates with the fuel nozzle; in the ignition and detonation section, a hot jet igniter 5 is located at the upper arc apex of the spiral fan-shaped detonation tube, with an axial distance of 1 to 2 times the equivalent diameter of the detonation tube from the nozzle, and a spiral tube section begins 0.5 to 1 times the equivalent diameter of the detonation tube after the hot jet igniter. After being decelerated and diffused by diffuser 1, the airflow is divided into two parts. One part flows into the fuel mixing section from the head intake cone 2 and mixes with the fuel injected from the fuel nozzle 4. The combustible mixture enters the ignition and detonation section and is ignited by the hot jet igniter 5. After undergoing the deflagration-to-detonation process, a detonation wave is formed. The other part flows through the outer wall of the spiral fan-shaped detonation tube 6 for cooling. The two airflows are mixed and stabilized in the outlet pressure stabilizing chamber 9 before being discharged into the turbine.

[0009] Preferably, the spiral fan-shaped detonation tube 6 includes an oil supply and mixing section and an ignition and detonation section. The oil supply and mixing section is a straight pipe section with a fan-shaped cross-section, and the ignition and detonation section is a spiral pipe section with a fan-shaped cross-section. Several detonation aiding obstacles 12 are provided in the ignition and detonation section. The two end faces of the detonation aiding obstacles 12 are both normal planes of the spiral axis of the spiral fan-shaped detonation tube 6. The blockage ratio of the detonation aiding obstacles 12 is between 0.3 and 0.6, and the interval between every two detonation aiding obstacles 12 is 0.8 to 1.2 times the equivalent diameter of the spiral fan-shaped detonation tube 6.

[0010] Specifically, the number of spiral fan-shaped detonation tubes arranged circumferentially is determined according to the inner and outer diameters of the spiral pulse detonation combustion chamber, and the selection range is between 3 and 12, with the corresponding fan-shaped angle ranging from 120° to 30°.

[0011] Specifically, the head intake cone has a square pyramid at the front and a column with a fan-shaped cross-section at the rear. The center of the column has a fuel supply channel and a mounting hole for the fuel nozzle 4.

[0012] Specifically, the outlet pressure stabilizing chamber has shock wave damping plates on its inner wall, which can weaken the intensity of the detonation wave and reduce the pulsation of the gas at the outlet of the detonation chamber. The number of shock wave damping plates is 1 to 3 depending on the axial length of the pressure stabilizing chamber.

[0013] Invention Effects

[0014] The technical advantages of this invention are as follows: The multi-tube spiral fan-shaped pulse detonation combustion chamber proposed in this invention has two beneficial effects: First, by using a fan-shaped cross-section detonation tube, the annular airflow channel of the engine is perfectly matched, improving the cross-sectional utilization rate of the flow channel, thereby increasing the thrust of the pulse detonation turbine engine; Second, by using a spiral detonation tube, the axial length of the pulse detonation combustion chamber is shortened, thereby shortening the overall length of the pulse detonation turbine engine, reducing the total weight of the engine, improving the thrust-to-weight ratio, and improving the engine rotor dynamics characteristics due to the shortened axial distance of the entire rotor system. Attached Figure Description

[0015] Figure 1 : Structural diagram of the present invention

[0016] Figure 2 : Structural diagram of the spiral sector-shaped detonation tube of the present invention

[0017] Figure 3 Left view of the oil supply and mixing section of the spiral fan-shaped detonation pipe.

[0018] Figure 4 Outlet pressure regulating chamber structure diagram

[0019] Figure 5 : A diagram of the head intake cone structure of an optimized scheme

[0020] Figure 6 : A structural diagram of an optimized outlet voltage regulator

[0021] Explanation of reference numerals in the attached diagram: 1-Diffuser, 2-Head intake cone, 3-Fuel supply pipe, 4-Fuel nozzle, 5-Hot jet igniter, 6-Spiral fan-shaped detonation tube, 7-Outer combustion chamber casing, 8-Inner combustion chamber casing, 9-Outlet pressure stabilizing chamber, 10-Support plate, 11-Spark plug, 12-Detonation aid obstruction, 13-Shock wave damping plate, 14-Connecting pipe, 15-Spiral guide plate. Detailed Implementation

[0022] The invention will be further explained below with reference to specific implementation examples.

[0023] See attached document Figure 1-4In this embodiment, the head intake cone 2 at the inlet of the spiral fan-shaped detonation tube 6 is fixed to the center of the fan-shaped cross-section of the spiral fan-shaped detonation tube by two support plates 10 and the fuel supply pipe 3. The center of the leeward side of the head intake cone 2 is fixed with a fuel nozzle 4 by a thread. Fuel is supplied to the fuel nozzle 4 through the fuel supply pipe 3 that passes through the combustion chamber 7 and the wall of the spiral fan-shaped detonation tube 6 and extends into the head intake cone 2. The hot jet igniter 5 is set at a distance of 1 to 2 times the equivalent diameter of the detonation tube downstream of the fuel nozzle 4 to ensure that the combustible mixture formed by the mixing of fuel and airflow can smoothly enter the interior of the hot jet igniter 5, and the axial distance between the hot jet igniter 5 and the nozzle 4 is not too long. The hot jet igniter 5 is located at the upper arc apex of the spiral fan-shaped detonation tube 6 and is integrally formed with it. Starting from 0.5 to 1 times the equivalent diameter of the detonation tube after the hot jet igniter 5, there is a section of spiral tube. Inside the spiral tube, there are several detonation aiding obstacles 12 integrally manufactured with the tube wall. The obstacle blockage ratio is between 0.3 and 0.6, and the obstacle spacing is 0.8 to 1.2 times the equivalent diameter of the spiral fan-shaped detonation tube, so as to ensure that the flow loss and flow capacity of the detonation chamber are considered while effectively shortening the DDT distance. Several spiral fan-shaped detonation tubes 6 are connected in parallel along the circumference and manufactured as a whole. They are installed in the annular cavity formed by the outer combustion chamber 7 and the inner combustion chamber 8 to match the annular airflow channel of the engine. The front end of the annular cavity is connected to the diffuser 1 by welding, and the rear end is connected to the outlet pressure stabilizing cavity 9 containing the shock wave damping plate 13 by welding.

[0024] The multi-tube spiral fan-shaped pulse detonation combustion chamber, when in operation, the high-velocity airflow from the upstream compressor is decelerated and diffused by the diffuser 1 and then divided into two parts. One part enters multiple spiral fan-shaped detonation tubes 6 through the head intake cone 2, and the other part flows through the outer wall of the spiral fan-shaped detonation tubes 6 to cool it. The airflow entering the spiral fan-shaped detonation tube 6 interacts with the fuel injected by the fuel nozzle 4 in the fuel supply mixing section, forming a fully mixed combustible mixture that flows downstream to fill the ignition and detonation section. At this time, the hot jet igniter 5 is also filled with combustible mixture. Then, the spark plug 11 in the hot jet igniter 5 ignites, and the hot jet igniter 5 generates a hot jet. The deflagration flame begins to be generated in the ignition and detonation section and spreads downstream. Under the influence of the detonation aiding obstacle 12, the flame undergoes a short deflagration-to-detonation process and finally forms a stable and self-sustaining detonation wave before reaching the outlet of the spiral fan-shaped detonation tube 6. After that, the airflow reaches the outlet of the detonation tube and mixes and stabilizes with the cooling airflow outside the detonation tube in the outlet pressure stabilizing chamber 9. Under the action of the shock wave resistance plate 13, the exhaust pulsation is further reduced. Finally, the stabilized airflow is discharged into the turbine and impacts the turbine to do work.

[0025] A further optimization of the present invention is as follows: the head intake cone 2 is a hollow structure, with a connecting pipe 14 extending from each side. Adjacent detonation pipes are interconnected through the connecting pipes. (Refer to the attached document.) Figure 5This structure can reduce the pressure from the downstream back-transmission pressure wave. On the other hand, the high-temperature combustion products generated by the ignition of one detonation tube are transmitted to two adjacent detonation tubes through the connecting pipe under the action of back-transmission pressure, igniting the fresh reactants in the adjacent detonation tubes. This can realize the control of multiple detonation chambers by one igniter, thereby reducing the number of jet igniters and reducing the weight of the entire detonation chamber.

[0026] A further optimization of the present invention is that a spiral guide plate 15 can be installed inside the outlet pressure stabilizing chamber 9, as shown in the attached figure. Figure 6 On the one hand, it can enhance the mixing of the cooling airflow on the outer wall of the detonation tube with the airflow at the outlet of the detonation tube, reducing the pulsation of the gas at the outlet of the detonation chamber. On the other hand, the spiral guide plate 15 guides the airflow to directly impact the turbine rotor at a suitable angle, thereby eliminating the turbine guide of the engine and further reducing the engine weight.

[0027] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A multi-tube spiral sector impulse detonation combustion chamber, characterized by: It includes a diffuser (1), an oil supply pipe (3), a multi-tube spiral fan-shaped detonation tube, an outdoor combustion chamber (7), an indoor combustion chamber (8), and an outlet pressure stabilizing chamber (9); the multi-tube spiral fan-shaped detonation tube consists of multiple spiral fan-shaped detonation tubes (6) arranged in parallel along the circumference in the annular cavity formed by the outdoor combustion chamber (7) and the indoor combustion chamber (8), and each spiral fan-shaped detonation tube (6) consists of an oil supply mixing section and an ignition detonation section; the oil supply mixing section is a section with a fan-shaped cross-section. The ignition and detonation section is a spiral section with a fan-shaped cross-section; the inlet of the fuel supply and mixing section is provided with a head intake cone (2), the front part of the head intake cone (2) is a square pyramid, and the rear part is a column with a fan-shaped cross-section. The center of the column is provided with a fuel supply channel and a fuel nozzle mounting hole. The fuel nozzle (4) is installed at the center of the leeward side of the head intake cone (2). The fuel supply pipe passes through the combustion chamber outside the casing (7) and the spiral fan-shaped detonation tube (6). The outer shell extends into the head intake cone (2) and communicates with the fuel nozzle (4); in the ignition and detonation section, the hot jet igniter (5) is set at the upper arc top of the spiral fan-shaped detonation tube (6), and the axial distance between it and the fuel nozzle (4) is 1 to 2 times the equivalent diameter of the spiral fan-shaped detonation tube. The spiral fan-shaped detonation tube (6) starts as a spiral tube 0.5 to 1 times the equivalent diameter of the detonation tube along the axial direction after the hot jet igniter (5); the airflow is decelerated and diffused by the diffuser (1). After compression, the airflow is divided into two parts. One part of the airflow flows into the fuel mixing section from the head intake cone (2) and mixes with the fuel sprayed from the fuel nozzle (4) to form a combustible mixture that enters the ignition and detonation section and is ignited at the hot jet igniter (5). After undergoing the deflagration-to-detonation process, a detonation wave is formed. The other part of the airflow flows through the outer wall of each spiral fan-shaped detonation tube (6) and cools it. The two parts of the airflow are mixed and stabilized in the outlet pressure stabilizing chamber (9) before being discharged into the turbine.

2. A multiple-pulse detonation combustor according to claim 1, wherein Several detonation aids (12) are provided in the ignition and detonation section. The two end faces of the detonation aids (12) are the normal plane of the spiral axis of the spiral fan-shaped detonation tube (6). The blockage ratio of the detonation aids (12) is between 0.3 and 0.

6. The interval between each two detonation aids (12) is 0.8 to 1.2 times the equivalent diameter of the spiral fan-shaped detonation tube (6).

3. A multiple-pulse detonation combustor according to claim 1, wherein The number of spiral fan-shaped detonation tubes (6) arranged circumferentially depends on the inner and outer diameters of the spiral pulse detonation combustion chamber, and the selection range is between 3 and 12, with the corresponding fan-shaped angle range being 120° to 30°.

4. A multiple-pulse detonation combustor according to claim 1, wherein The head intake cone (2) is a hollow structure with a connecting pipe (14) extending from each side. Adjacent detonation tubes are connected to each other through the connecting pipe (14). The connecting pipe (14) is configured to transfer the high-temperature combustion products generated by the ignition of one detonation tube to the adjacent detonation tube under the action of reverse pressure, so as to ignite the fresh reactants in the adjacent detonation tube.

5. A multiple-pulse detonation combustor according to claim 1, wherein The inner wall of the outlet pressure stabilization cavity is provided with shock wave damping plates to weaken the intensity of the detonation wave and reduce the pulsation of the gas at the outlet of the detonation chamber, and the number of the shock wave damping plates is 1-3 according to the axial length of the pressure stabilization cavity.

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