A pulse detonation rapid initiation combustion chamber and engine

Abstract

This invention belongs to the field of aero-engines, specifically relating to a pulse detonation rapid initiation combustor and engine. In one pulse detonation rapid initiation combustor, a first stream of liquid hydrocarbon fuel and air enters the pre-combustion chamber through the inlet, is ignited by an igniter, and undergoes stable combustion to form high-temperature gas. The high-temperature gas exits from the pre-combustion chamber outlet and enters the upstream of the detonation section. A second stream of liquid hydrocarbon fuel, heated within a sandwich structure, is atomized and sprayed into the upstream of the detonation section. Air enters the upstream of the detonation section through a channel between the outer wall of the pre-combustion chamber and the inner wall of the ignition section. The high-temperature gas, the atomized second stream of liquid hydrocarbon fuel, and the air converge and mix in the upstream of the detonation section and are ignited by the high-temperature gas, completing the initiation process. This invention, firstly, meets the need for rapid initiation and self-sustaining operation of liquid hydrocarbon fuels, especially aviation kerosene, which are difficult to initiate; secondly, it shortens the DDT distance, thereby shortening the length of the detonation chamber.

Description

Technical Field

[0001] This invention belongs to the field of aero-engines, specifically relating to a pulse detonation rapid initiation combustion chamber and engine. Background Technology

[0002] The Pulsed Detonation Engine (PDE) is a power unit that uses pulse detonation combustion technology to generate power. Previous research results have demonstrated its advantages in terms of rapid combustion heat release, high thermal cycle efficiency, and self-pressurization.

[0003] Rapid initiation and self-sustaining are core challenges in pulse detonation combustion technology. Previous studies have primarily employed highly reactive gaseous fuels such as hydrogen, methane, and ethylene to quickly generate stable, self-sustaining detonation waves. Liquid hydrocarbon fuels (such as aviation kerosene), due to their large molecular weight, low reactivity, and the physical processes of atomization and evaporation, result in a longer combustion heat release zone and a slower deflagration-to-detonation transition (DDT) process, making initiation difficult or preventing the formation of stable, self-sustaining detonation waves. However, liquid hydrocarbon fuels (especially aviation kerosene) are currently the most widely used and mature fuels in aero-engines. Therefore, achieving rapid initiation and self-sustaining of liquid hydrocarbon fuels in a pulse detonation combustion chamber has become a pressing engineering challenge. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a pulse detonation rapid initiation combustion chamber and engine. Firstly, this invention meets the need for rapid initiation and self-sustaining operation of liquid hydrocarbon fuels, especially aviation kerosene, which are difficult to detonate. Secondly, by setting up a pre-combustion structure and using the combustion heat generated within the pre-combustion structure to heat the liquid hydrocarbon fuel within the sandwich structure, its atomization efficiency is improved, thereby shortening the DDT distance and consequently reducing the length of the detonation chamber.

[0005] This invention includes the following technical solutions: The first aspect of this invention provides a pulse detonation rapid initiation combustion chamber, comprising an ignition section and a detonation section connected together. A pre-combustion chamber is provided within the ignition section, and the wall of the pre-combustion chamber is configured as a sandwich structure for the passage of a second stream of liquid hydrocarbon fuel. A first stream of liquid hydrocarbon fuel and air enter the pre-combustion chamber through the inlet, are ignited by an igniter, and undergo stable combustion to form high-temperature gas. The high-temperature gas exits from the pre-combustion chamber outlet and enters the upstream of the detonation section. The second stream of liquid hydrocarbon fuel is heated within the sandwich structure and then atomized, entering the upstream of the detonation section. Air enters the upstream of the detonation section through a channel between the outer wall of the pre-combustion chamber and the inner wall of the ignition section. The high-temperature gas, the atomized second stream of liquid hydrocarbon fuel, and the high-temperature gas converge and mix in the upstream of the detonation section and are ignited by the high-temperature gas, completing the initiation process.

[0006] Furthermore, an obstacle structure is provided within the detonation section.

[0007] Furthermore, the obstacle structure is arranged along the axial and circumferential directions of the detonation section.

[0008] Furthermore, the inlet of the pre-combustion chamber is provided with a first atomizing structure, which is used to introduce atomized first-path liquid hydrocarbon fuel into the pre-combustion chamber; the outlet of the sandwich structure is provided with a second atomizing structure, which is used to atomize and spray out heated second-path liquid hydrocarbon fuel.

[0009] Furthermore, the inlet of the pre-combustion chamber is provided with a first swirling structure, which is arranged around the first atomizing structure.

[0010] Furthermore, a second swirling structure is provided between the annulus formed between the outer wall of the pre-combustion chamber and the inner wall of the ignition section. The second swirling structure is used to accelerate the mixing of high-temperature combustion gas, atomized second-path liquid hydrocarbon fuel, and air.

[0011] Furthermore, the thickness of the sandwich structure is 1mm-4mm.

[0012] Furthermore, the ratio of the maximum inner diameter of the pre-combustion chamber to the inner diameter of the ignition section is 0.55-0.85.

[0013] Furthermore, the pre-combustion chamber is located at the center of the ignition section.

[0014] A second aspect of the present invention provides an engine including the combustion chamber described above.

[0015] By adopting the above technical solution, the present invention has the following advantages: 1. The first aspect of this invention meets the need for rapid initiation and self-sustaining operation of liquid hydrocarbon fuels, especially aviation kerosene, which are difficult to detonate. It can accelerate the application of pulse detonation combustion technology in the engineering field (especially the aerospace field) and effectively solve practical engineering problems such as the safety, storage, and transportation of gaseous fuels. The second aspect is that by setting a pre-combustion structure and heating the liquid hydrocarbon fuel in the sandwich structure with the heat generated by combustion in the pre-combustion structure, the atomization efficiency is improved, thereby shortening the DDT distance and thus shortening the detonation chamber length.

[0016] 2. The second liquid hydrocarbon fuel of the present invention flows through the sandwich structure of the pre-combustion chamber, which absorbs heat from the pre-combustion chamber wall and forms a cooling protection for the pre-combustion chamber wall, thereby improving the life of the pre-combustion chamber; on the other hand, it heats the second liquid hydrocarbon fuel, accelerates the atomization and evaporation rate of the second liquid hydrocarbon fuel, thereby further shortening the length of the detonation chamber.

[0017] 3. By setting a second swirl structure, the present invention enhances the mixing of high-temperature combustion gas, atomized second-path liquid hydrocarbon fuel and air, which facilitates rapid initiation and self-sustaining.

[0018] 4. The present invention has a simple overall structure, high reliability, and is easy to implement and apply in engineering.

[0019] 5. The rapid detonation device of the present invention effectively improves the ignition and detonation energy and the activity of the gas mixture by utilizing the pre-combustion chamber scheme. It does not require additional devices such as hydrogen dosing, oxygen supplementation, or heating to improve the activity of the gas mixture, making the system relatively simpler and easier to implement. 6. Existing pulse detonation combustion chambers that operate with liquid hydrocarbon fuels mainly use relatively highly reactive fuels such as gasoline and methanol. Liquid aviation kerosene still faces significant challenges in terms of initiation and self-sustaining. The device of this invention is expected to achieve reliable ignition, initiation, and self-sustaining of liquid kerosene.

[0020] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the 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 based on these drawings without creative effort.

[0022] Figure 1This is a schematic diagram of the structure of a pulse detonation rapid initiation combustion chamber according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the pre-combustion chamber in an embodiment of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the pre-combustion chamber in an embodiment of the present invention. Figure 2 ; Figure 4 This is a schematic diagram of the first swirl structure in an embodiment of the present invention. Figure 1 ; Figure 5 This is a schematic diagram of the first swirl structure in an embodiment of the present invention. Figure 2 ; Figure 6 This is a schematic diagram of the second swirl structure in an embodiment of the present invention. Figure 1 ; Figure 7 This is a schematic diagram of the second swirl structure in an embodiment of the present invention. Figure 2 ; Figure 8 This is a schematic diagram of the second swirl structure in an embodiment of the present invention. Figure 3 ; In the diagram, 1-ignition section, 2-pre-combustion chamber, 3-distributor, 4-first pipe, 5-second pipe, 6-first atomizing structure, 7-igniter, 8-detonation section, 2.1-first swirl structure, 2.2-recirculation zone, 2.3-second swirl structure, 2.4-outer wall, 2.5-inner wall, 2.6-second atomizing structure. Detailed Implementation

[0023] The following description provides many different embodiments or examples for implementing various features of the invention. The elements and arrangements described in the specific examples below are only for concise expression of the invention and are merely examples, not intended to limit the invention.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the prior art, the patent with publication number CN110131071B discloses the use of fuel oil as fuel. However, in this technology, the fuel oil and oxidizing gas are first introduced into the main detonation chamber for mixing before ignition, and the fuel oil is only atomized. This method has the following problems: (1) The patent does not preheat the fuel oil, and the fuel oil atomization and evaporation efficiency is low, which affects the rapid detonation and self-sustaining of the fuel oil; (2) The multi-stage ignition and step-by-step detonation structure makes the system relatively more complex, and it is evident that the length and weight of the detonation chamber will be increased, reducing the thrust-to-weight ratio of the engine.

[0026] Compared with the prior art, on the one hand, the ignition of the pre-combustion chamber 2 and the air and liquid hydrocarbon fuel used for detonation in this invention are carried out simultaneously, resulting in high detonation efficiency; and the liquid hydrocarbon fuel used for detonation is heated, which increases the chemical activity of the fuel, accelerates the atomization and evaporation of the fuel, and enables the liquid fuel to detonate quickly, which has the advantage of further shortening the DDT distance; on the other hand, the structure of this invention is simpler, smaller in size and weight, and has the advantage of improving the thrust-to-weight ratio of the engine.

[0027] The first aspect of this embodiment provides a pulse detonation rapid initiation combustion chamber, combined with... Figure 1 As shown, it includes a connected ignition section 1 and a detonation section 8. A pre-combustion chamber 2 is provided within the ignition section 1. The wall of the pre-combustion chamber 2 is configured as a sandwich structure for the passage of a second stream of liquid hydrocarbon fuel. The first stream of liquid hydrocarbon fuel and air enter the pre-combustion chamber 2 through the inlet and are ignited by the igniter 7, forming a high-temperature gas. The high-temperature gas ( Figure 1 The second stream of liquid hydrocarbon fuel (Wg) is discharged from the outlet of the pre-combustion chamber 2 and enters the upstream of the detonation section 8. After being heated in the sandwich structure, the second stream of liquid hydrocarbon fuel (Wg) is sprayed out as atomized liquid hydrocarbon fuel. Figure 1 (Wf) enters the upstream of the detonation stage 8 and the air ( Figure 1 The gas enters the upstream of the detonation section 8 through the channel between the outer wall 2.4 of the pre-combustion chamber 2 and the inner wall of the ignition section 1. The high-temperature combustion gas, the atomized second-path liquid hydrocarbon fuel, and the high-temperature combustion gas converge and mix upstream of the detonation section 8 and are ignited by the high-temperature combustion gas to complete the detonation process. The liquid hydrocarbon fuel (first-path liquid hydrocarbon fuel and second-path liquid hydrocarbon fuel) can be fuel oil or kerosene.

[0028] The structure of this embodiment incorporates a pre-combustion chamber 2 within the ignition section 1. Air and the first stream of liquid hydrocarbon fuel are combusted within the pre-combustion chamber 2 to form high-temperature gas, which serves as a high-energy ignition source for the detonation chamber. This also increases the enthalpy of the gas mixture upstream of the detonation section 8, facilitating rapid detonation of the liquid fuel. The sandwich structure of the pre-combustion chamber 2 heats the second stream of liquid hydrocarbon fuel, resulting in lower viscosity and higher activity, making it easier to atomize and burn.

[0029] The pre-combustion chamber 2 has a double-layered, hollow, annular structure. The double layers form a sandwich structure, and the hollow inner cavity is used for combustion; combined with Figure 2 , Figure 3 As shown, Figure 2 In the combustion chamber, from the inlet to the outlet, the inner diameter of the combustion chamber first increases, then decreases, and finally remains constant. Figure 3 In the combustion chamber, from the inlet to the outlet, the inner diameter of the combustion chamber remains constant at first, and then gradually decreases.

[0030] To further shorten the distance of DDT, combined with Figure 1 As shown, an obstacle structure is provided inside the detonation section 8.

[0031] It is worth noting that as long as an obstacle structure is set within the detonation section 8, the goal of shortening the DDT can be achieved. Therefore, any arrangement and method of the obstacle structure within the detonation section 8 should be included in this embodiment. Based on the obstacle structure, to further shorten the DDT distance, the obstacle structure is arranged along the axial and circumferential directions of the detonation section 8. The obstacle structure in this embodiment can be uniformly or non-uniformly arranged; and the height of the obstacle structure along the path can vary depending on the initiation and self-sustaining characteristics of different fuels. For example, from upstream to downstream, the axial spacing of the obstacle structure gradually increases, while the height of the obstacle structure gradually decreases.

[0032] To improve the ignition efficiency of the pre-combustion chamber 2, a first atomizing structure 6 is provided at the inlet of the pre-combustion chamber 2. The first atomizing structure 6 is used to introduce atomized first-path liquid hydrocarbon fuel into the pre-combustion chamber 2. For example, the first atomizing structure 6 can be a nozzle.

[0033] After the second stream of liquid hydrocarbon fuel enters the sandwich structure, the combustion heat in the pre-combustion chamber 2 heats the fuel, resulting in lower viscosity and higher reactivity, making it easier to atomize and burn. To ensure complete atomization of the second stream of liquid hydrocarbon fuel ejected from the sandwich structure, a second atomizing structure 2.6 is provided at the outlet of the sandwich structure. This structure atomizes and ejects the heated second stream of liquid hydrocarbon fuel. Figures 6-8 As an example, the second atomizing structure 2.6 can be a nozzle. Figure 6 , Figure 7 and Figure 8 Various nozzle structures capable of achieving the objectives of this invention are shown.

[0034] Combination Figure 1As shown, the inlet of the pre-combustion chamber 2 is provided with a connected first swirl structure 2.1, which surrounds the first atomizing structure 6. The purpose is to enhance the mixing of the first-path liquid hydrocarbon fuel with air and to form a recirculation zone 2.2 at the head of the pre-combustion chamber 2, facilitating rapid ignition and stable combustion in the pre-combustion chamber 2. Figure 4 , Figure 5 As shown, for example, the first swirling structure 2.1 can be an axial swirler ( Figure 4 The left side of the figure shows a schematic diagram of an axial cyclone separator installed at the inlet of the pre-combustion chamber 2, and the right side shows a front view of the axial cyclone separator; the first cyclone structure 2.1 can also be a radial cyclone separator ( Figure 5 The left side of the figure shows a schematic diagram of the axial cyclone separator installed at the inlet of the pre-combustion chamber 2, and the right side shows a front view of the axial cyclone separator.

[0035] To enhance the mixing of high-temperature combustion gas, atomized second-stage liquid hydrocarbon fuel, and air, a second swirling structure 2.3 is provided between the outer wall 2.4 of the pre-combustion chamber 2 and the inner wall of the ignition section 1 to form an annulus. The second swirling structure 2.3 is used to accelerate the mixing of high-temperature combustion gas, atomized second-stage liquid hydrocarbon fuel, and air.

[0036] Furthermore, Wa and Wg can be set to opposite swirl directions, which can further shear and atomize Wf, making it more favorable for ignition and detonation of the mixture. The swirl directions of Wa and Wg can be controlled by the first swirl structure 2.1 and the second swirl structure 2.3.

[0037] Combination Figure 2 , Figure 3 As shown, the wall of the pre-combustion chamber 2 includes an outer wall 2.4 and an inner wall 2.5, which form a sandwich structure. The distance between the outer wall 2.4 and the inner wall 2.5 is δ, and the value of δ is not limited in this invention. Preferably, the thickness of the sandwich structure is 1mm-4mm. Furthermore, from the main combustion zone of the pre-combustion chamber 2 to the outlet of the pre-combustion chamber 2, the δ value gradually increases; the δ value is smaller at the main combustion zone of the pre-combustion chamber 2, which can accelerate the flow of the second-path liquid hydrocarbon fuel in this area, allowing the second-path liquid hydrocarbon fuel to quickly absorb heat and flow backward; at the same time, it can avoid excessive heat absorption and low flow rate of the second-path liquid hydrocarbon fuel leading to carbon buildup and coking; the δ value is larger at the outlet of the pre-combustion chamber 2, which slows down the flow rate of the second-path liquid hydrocarbon fuel, which is beneficial to increasing the static pressure of the second-path liquid hydrocarbon fuel in this area, allowing the second-path liquid hydrocarbon fuel to be rapidly atomized after passing through the nozzle.

[0038] Combination Figure 1As shown, the ignition section 1 is cylindrical with an inner diameter of D1, and the pre-combustion chamber 2 has a maximum inner diameter of D2. The cross-sectional area ratio of the ignition section 1 and the pre-combustion chamber 2 needs to be designed appropriately, taking into account the following aspects: a) ensuring that the pre-combustion chamber 2 can ignite quickly and operate stably; b) ensuring that the gas energy at the outlet of the pre-combustion chamber 2 is sufficient to ignite the oil-gas mixture at its tail; c) minimizing the amount of air diverted by the pre-combustion chamber 2 based on the above two points, so as to ensure that the main detonation gas flow has sufficient work capacity. Therefore, the ratio of the maximum inner diameter of the pre-combustion chamber 2 to the inner diameter of the ignition section 1 is 0.55-0.85.

[0039] Combination Figure 1 As shown, the pre-combustion chamber 2 is located in the center of the ignition section 1, which facilitates the uniform mixing of the high-temperature gas at the tail of the pre-combustion chamber 2 with the mainstream air in the detonation chamber, and is beneficial to the uniform development and flow of the detonation gas along the flow path.

[0040] Combination Figure 1 As shown, the inlet of the pre-combustion chamber 2 is connected to the liquid hydrocarbon fuel tank via a first pipe 4, and the sandwich structure is connected to the liquid hydrocarbon fuel tank via a second pipe 5. The first pipe 4 and the second pipe 5 are connected to the liquid hydrocarbon fuel tank via a distributor 3.

[0041] The second aspect of this embodiment provides an engine including the combustion chamber described above.

[0042] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more.

[0043] All terms used in this invention (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this invention pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0044] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pulse detonation rapid initiation combustion chamber, characterized in that, The system includes a connected ignition section (1) and a detonation section (8). The ignition section (1) is equipped with a pre-combustion chamber (2). The wall of the pre-combustion chamber (2) is configured as a sandwich structure for the passage of the second liquid hydrocarbon fuel. The first liquid hydrocarbon fuel and air enter the pre-combustion chamber (2) through the inlet and are ignited by the igniter (7) to form high-temperature gas. The high-temperature gas is discharged from the outlet of the pre-combustion chamber (2) and enters the upstream of the detonation section (8). The second liquid hydrocarbon fuel is heated in the sandwich structure and then sprayed out as atomized second liquid hydrocarbon fuel and enters the upstream of the detonation section (8). Air enters the upstream of the detonation section (8) through the channel between the outer wall (2.4) of the pre-combustion chamber (2) and the inner wall (2.5) of the ignition section (1). The high-temperature gas, the atomized second liquid hydrocarbon fuel and air are mixed and ignited by the high-temperature gas in the upstream of the detonation section (8) to complete the detonation process.

2. The pulse detonation rapid initiation combustion chamber according to claim 1, characterized in that, The detonation section (8) is equipped with an obstacle structure.

3. The pulse detonation rapid initiation combustion chamber according to claim 2, characterized in that, The obstacle structure is arranged along the axial and circumferential directions of the detonation section (8).

4. The pulse detonation rapid initiation combustion chamber according to claim 1, characterized in that, The inlet of the pre-combustion chamber (2) is provided with a first atomizing structure (6), which is used to introduce atomized first-path liquid hydrocarbon fuel into the pre-combustion chamber (2); the outlet of the sandwich structure is provided with a second atomizing structure (2.6), which is used to atomize and spray out heated second-path liquid hydrocarbon fuel.

5. A pulse detonation rapid initiation combustion chamber according to claim 4, characterized in that, The inlet of the pre-combustion chamber (2) is provided with a first swirling structure (2.1) that is connected to the first swirling structure (2.1), which is arranged around the first atomizing structure (6).

6. The pulse detonation rapid initiation combustion chamber according to claim 1, characterized in that, A second swirling structure (2.3) is provided between the annulus formed between the outer wall (2.4) of the pre-combustion chamber (2) and the inner wall of the ignition section (1). The second swirling structure (2.3) is used to accelerate the mixing of high-temperature combustion gas, atomized second-path liquid hydrocarbon fuel and air.

7. The pulse detonation rapid initiation combustion chamber according to claim 1, characterized in that, The thickness of the sandwich structure is 1mm-4mm.

8. The pulse detonation rapid initiation combustion chamber according to claim 1, characterized in that, The ratio of the maximum inner diameter of the pre-combustion chamber (2) to the inner diameter of the ignition section (1) is 0.55-0.

85.

9. A pulse detonation rapid initiation combustion chamber according to claim 1, characterized in that, The pre-combustion chamber (2) is located at the center of the ignition section (1).

10. An engine, characterized in that, It includes a combustion chamber as described in any one of claims 1-9.

Images