Water ramjet engine with bluff body cavity powder inlet structure

Abstract

The invention discloses a water ramjet engine with a bluff body cavity powder inlet structure. The water ramjet engine comprises a combustion chamber; the fuel gas generator is used for providing high-temperature fuel gas for the combustion chamber, and the fuel gas generator is fixedly connected to the front end of the combustion chamber; the powder conveying pipe is fixedly assembled in the fuel gas generator, the front end of the powder conveying pipe is connected with the powder supply device, and the rear end of the powder conveying pipe extends into the combustion chamber from a gas inlet in the front end of the combustion chamber; the exhaust nozzle is fixedly communicated with the rear end of the combustion chamber; and the bluff body is fixedly communicated with the rear end of the powder conveying pipe, and an opening of the bluff body faces the exhaust nozzle. The device has a good mixing combustion effect, and meanwhile deposition on the wall face of the combustion chamber and the surface of the bluff body can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water ramjet engine, in particular to a water ramjet engine with powder inlet structure of blunt body cavity. BACKGROUND

[0002] The powder water ramjet engine is a special type of ramjet engine, which uses metal powder such as magnesium, aluminum, boron, etc. as fuel, and uses water as oxidant and working medium. It uses the violent chemical reaction between metal powder and water under high water temperature and pressure to release a large amount of heat energy and hydrogen, thereby generating thrust. The powder water ramjet engine has the characteristics of high ignition temperature, long ignition delay time and combustion time due to the complexity of the ignition combustion process, and high particle density and mass.

[0003] At present, for the water ramjet engine, the main way to mix and stabilize the flame is to install a single blunt body in the combustion chamber through fixed support plates or to supply powder to the combustion chamber through a powder swirl injector. However, it is difficult to install a blunt body with fixed support plates, and the fixed support plates have a great influence on the flow field in the engine, which is easy to form deposition on the surface of the combustion chamber wall and the blunt body. The powder swirl injector promotes the powder mixing process through swirl. The fluidization pressure of this type of injector is high, and the fluidization gas flow rate is fast, which can make the powder quickly disperse uniformly in the combustion chamber under the action of drag and centrifugal inertia, achieving the purpose of mixing and combustion. However, this type of injection method is easy to cause the powder to form deposition on the wall of the engine combustion chamber under the action of centrifugal inertia. The deposition of powder on the wall of the engine combustion chamber will destroy the integrity of the flow field in the combustion chamber, which is easy to cause combustion oscillation, noise and other factors that are not conducive to the normal operation of the engine. SUMMARY

[0004] Therefore, it is necessary to provide a water ramjet engine with powder inlet structure of blunt body cavity to solve the above technical problems, which has good mixing and combustion effect and can reduce the deposition on the wall of the combustion chamber and the surface of the blunt body.

[0005] The present application provides a water ramjet engine with powder inlet structure of blunt body cavity, comprising: a combustion chamber; a gas generator for providing high-temperature gas to the combustion chamber, the gas generator being fixedly connected to the front end of the combustion chamber; a powder transport pipe, the powder transport pipe being fixedly assembled in the gas generator, the front end of the powder transport pipe being connected to the powder supply device, and the rear end of the powder transport pipe extending into the interior of the combustion chamber from the air inlet of the front end of the combustion chamber; a tail nozzle fixedly connected to the rear end of the combustion chamber; A conical cylinder-shaped bluff body is fixedly connected with the rear end of the powder conveying pipe, and the opening of the bluff body faces the tail nozzle.

[0006] In one of the embodiments, the axis of the bluff body is collinear with the axis of the combustion chamber.

[0007] In one of the embodiments, the included angle between the generatrix of the bluff body and the axis is 25°-60°.

[0008] In one of the embodiments, the gas generator is provided with an annular sealing plate, an outer shell, an inner shell, an annular propellant blocking plate and an annular end-burning double-base propellant column. Both the outer shell and the inner shell are cylindrical, and the axes of both are coincident with the axis of the annular sealing plate. Both the outer shell and the inner shell are fixedly connected to the side of the annular sealing plate facing the combustion chamber, the inner shell is arranged inside the outer shell, and the axial diameter of the inner shell is less than or equal to half of the axial diameter of the outer shell. The rear end of the outer shell is fixedly connected with the front end of the combustion chamber through a flange. The annular end-burning double-base propellant column is arranged in the annular cylindrical cavity formed between the outer shell and the inner shell, the annular propellant blocking plate is arranged behind the annular end-burning double-base propellant column, and the outer side wall of the annular propellant blocking plate abuts against the inner side wall of the outer shell.

[0009] In one of the embodiments, the powder conveying pipe comprises, in the powder conveying direction, a throttling cone pipe section, a flow control pipe section and a support pipe section fixedly connected in sequence. The opening of the throttling cone pipe section faces the annular sealing plate, the opening of the throttling cone pipe section is fitted to the inner side wall of the annular sealing plate, and the throttling cone pipe section is fixedly connected with the annular sealing plate. The outer side of the flow control pipe section is fixedly assembled with an adjustable ball valve through a threaded joint. The outer side wall of the support pipe section is integrally connected with a support member, the support member is annular columnar, the front end of the support member is fixedly connected with the rear end of the inner shell in the axial direction, and the outer diameter of the support member is equal to the outer diameter of the inner shell. The annular propellant blocking plate is sleeved on the outer side of the support member, and the annular propellant blocking plate is uniformly provided with a plurality of gas through holes.

[0010] In one of the embodiments, the inner end of the support pipe section is provided with a straight-flow nozzle.

[0011] In one of the embodiments, the side wall of the combustion chamber is provided with at least one injection hole for injecting water into the combustion chamber. In the axial direction of the combustion chamber, the injection hole is located behind the bluff body.

[0012] In one of the embodiments, an annular heat insulation layer is arranged between the annular sealing plate and the annular end-burning double-base propellant column, and the annular heat insulation layer is sleeved on the inner shell.

[0013] The beneficial effects of the present application are: the water ramjet engine with the bluff body cavity powder inlet structure has the cone cylinder shaped bluff body fixed through the powder conveying pipe extending into the combustion chamber, without fixing through the fixing support plate and the like, reducing the influence on the flow in the combustion chamber and reducing the deposition of the combustion chamber wall surface and the bluff body surface. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The overall structure schematic diagram of the water ramjet engine with the bluff body cavity powder inlet structure provided by the embodiment of the present application is provided. Figure 2 For Figure 1 The cross-sectional structure schematic diagram along the combustion chamber axis is one of the following: Figure 3 The cross-sectional schematic diagram along the gas generator axis after the gas generator and the powder conveying pipe are assembled is one of the following: Figure 4 The assembly relationship view of the powder conveying pipe and the bluff body is provided. Figure 5 The structure schematic diagram of the annular medicine blocking plate is provided. Figure 6 The combustion chamber front end flow field streamline diagram provided by the embodiment of the present application is provided. Figure 7 The particle trajectory diagram in the combustion chamber provided by the embodiment of the present application is provided.

[0015] The reference signs are explained as follows: 100, combustion chamber; 200, gas generator; 210, annular sealing plate; 220, outer shell; 230, inner shell; 240, annular heat insulation layer; 250, annular medicine blocking plate; 260, annular end-burning double-base propellant column; 300, powder conveying pipe; 310, throttling cone pipe section; 320, flow control pipe section; 330, support pipe section; 340, adjustable ball valve; 350, support; 360, gas through hole; 370, straight-flow nozzle; 400, tail nozzle; 500, bluff body. DETAILED DESCRIPTION

[0016] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings.

[0017] It should be noted that, in the description of the present application, "upper", "lower", "top", "bottom", orientation or position relationship are based on the drawings.Figure 1 It is to be understood that the orientation terms are used only to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0018] In one embodiment, as shown in Figure 1 and Figure 2 The water ramjet engine with blunt cavity powder inlet structure of the present embodiment comprises: A combustion chamber 100 for powder particle and water vapor mixture combustion.

[0019] A gas generator 200 for providing high-temperature gas to the combustion chamber 100, the gas generator 200 is fixedly connected to the front end of the combustion chamber 100. The high-temperature gas is used for the mixture of powder particles and water vapor.

[0020] In the present embodiment, the wall surface of the front end of the combustion chamber 100 and the rear end of the gas generator 200 is an inclined wall surface, which aims to reduce the size of the air inlet at the front end of the combustion chamber 100, improve the sealing performance of the combustion chamber 100, and enhance the combustion effect of the powder particles.

[0021] A powder transport pipe 300 fixedly assembled in the gas generator 200, the front end of the powder transport pipe 300 is connected to the powder supply device, and the rear end of the powder transport pipe 300 extends into the combustion chamber 100 from the air inlet at the front end of the combustion chamber 100.

[0022] Specifically, the distance from the rear end of the powder transport pipe 300 to the inside of the combustion chamber 100 through the air inlet at the front end of the combustion chamber 100 is greater than the horizontal projection distance in the inclined direction of the front end of the combustion chamber 100.

[0023] A tail nozzle 400 fixedly connected to the rear end of the combustion chamber 100. The tail nozzle 400 is used to compress high-temperature and high-pressure gas and generate thrust, etc.

[0024] A conical cylinder-shaped blunt body 500 fixedly connected to the rear end of the powder transport pipe 300, the opening of the blunt body 500 faces the tail nozzle 400. The blunt body 500 is fixed by the powder transport pipe 300 extending into the combustion chamber 100, without the need for fixing by a fixed support plate or the like, reducing the impact on the flow in the combustion chamber 100 and reducing the deposition of the combustion chamber 100 wall surface and the blunt body 500 surface.

[0025] The obturator 500 in the embodiment is a conical cylinder. After the powder enters the combustion chamber 100 through the obturator 500, a symmetrical detached vortex with a low air flow speed is formed in the rear edge area of the obturator 500, which can quickly spread the powder particles, reduce the deposition of the powder particles on the wall surface of the combustion chamber 100 and the wall surface of the obturator 500, and increase the residence time of the powder particles, thus creating favorable conditions for the temperature increase of the powder particles and promoting the ignition process of the powder particles, thereby achieving the effect of improving the combustion efficiency of the engine.

[0026] In one of the embodiments, the axis of the obturator 500 and the axis of the combustion chamber 100 are collinear, which can ensure that the outlet of the powder particles is located at the center of the combustion chamber 100 and ensure the diffusion space of the powder particles.

[0027] In one of the embodiments, the included angle between the generatrix of the obturator 500 and the axis is 25°-60°. Preferably, the included angle between the generatrix of the obturator 500 and the axis is 45°, so that the detached vortex formed is least affected by the water vapor vortex and the high-temperature gas vortex, thereby improving the combustion efficiency in the combustion chamber.

[0028] In one of the embodiments, as shown in Figure 3 and Figure 4 , the gas generator 200 is provided with an annular sealing plate 210, an outer shell 220, an inner shell 230, an annular propellant blocking plate 250, and an annular end-burning double-base propellant column 260.

[0029] The outer shell 220 and the inner shell 230 are both cylindrical and their axes are coincident with the axis of the annular sealing plate 210. The outer shell 220 and the inner shell 230 are both fixedly connected to one side of the annular sealing plate 210 facing the combustion chamber 100. The inner shell 230 is arranged inside the outer shell 220, and the axial diameter of the inner shell 230 is less than or equal to half of the axial diameter of the outer shell 220.

[0030] The rear end of the outer shell 220 is fixedly connected to the front end of the combustion chamber 100 through a flange, thereby ensuring the sealing of the high-temperature gas.

[0031] The annular end-burning double-base propellant column 260 is arranged in the annular cylindrical cavity formed between the outer shell 220 and the inner shell 230. The annular propellant blocking plate 250 is arranged behind the annular end-burning double-base propellant column 260, and the outer side wall of the annular propellant blocking plate 250 abuts against the inner side wall of the outer shell 220.

[0032] Specifically, the annular end-burning double-base propellant column 260 in the embodiment can be a double-base propellant with high nitrogen content, low mechanical sensitivity, and high content of combustion product gas. The annular end-burning double-base propellant column 260 provides high-temperature gas for the water ramjet engine to ensure that the reaction of the powder particles and the water vapor reaches the ignition temperature. The annular propellant blocking plate 250 prevents large propellant fragments generated during the combustion of the propellant from blocking the nozzle.

[0033] An annular heat insulation layer 240 is arranged between the annular sealing plate 210 and the annular end-burning double-base grain column 260, and is sleeved on the inner shell 230. The annular heat insulation layer 240 provides thermal protection for the gas generator 200 and protects the wall surface.

[0034] In one embodiment, as shown in the figure, the powder conveying pipe 300 includes, in the powder conveying direction, a throttling cone pipe segment 310, a flow control pipe segment 320 and a support pipe segment 330 fixedly connected in sequence. Figure 5

[0035] The opening of the throttling cone pipe segment 310 is directed towards the annular sealing plate 210, and the opening of the throttling cone pipe segment 310 is in abutment with the inner side wall of the annular sealing plate 210. The throttling cone pipe segment 310 is fixedly connected with the annular sealing plate 210. The throttling cone pipe segment 310 can reduce the powder flow and seal the inside of the inner shell 230.

[0036] The outer side of the flow control pipe segment 320 is fixedly assembled with an adjustable ball valve 340 through a threaded joint. The adjustable ball valve 340 is used to further throttle and control the powder flow.

[0037] The outer side wall of the support pipe segment 330 is integrally connected with a support piece 350. The support piece 350 is annular and columnar. The front end of the support piece 350 is fixedly connected with the rear end of the inner shell 230 in the axial direction. The outer diameter of the support piece 350 is equal to the outer diameter of the inner shell 230. The outer diameter of the support piece 350 is equal to the outer diameter of the inner shell 230 and is fixed in the axial direction, which can prevent high-temperature gas from escaping into the inside of the inner shell 230 and damaging the powder conveying pipe.

[0038] The annular propellant blocking plate 250 is sleeved on the outer side of the support piece 350, and the annular propellant blocking plate 250 is uniformly provided with a plurality of gas through holes 360. Specifically, the gas through holes 360 in the embodiment are rectangular.

[0039] In one embodiment, a straight-flow nozzle 370 is arranged inside the end of the support pipe segment 330. The straight-flow nozzle 370 can make the powder particles more dispersed in the cavity structure area, accelerate the temperature increasing rate in the high-temperature area, and significantly improve the mixing and combustion efficiency of the powder fuel and water vapor.

[0040] In one embodiment, at least one injection hole for injecting water into the combustion chamber 100 is arranged on the side wall of the combustion chamber 100. The injection hole is located behind the bluff body 500 in the axial direction of the combustion chamber 100. A spiral nozzle is preferably arranged inside the injection hole to inject water into the combustion chamber 100, and the water outlet direction of the spiral nozzle is preferably inclined to the bluff body 500. The water entering the combustion chamber 100 will form water vapor and mix with the powder particles for combustion under the action of high-temperature gas.

[0041] ​In a specific embodiment, two groups of water injection holes are symmetrically arranged on the wall of the combustion chamber 100, and along the axis direction of the combustion chamber 100, the first group of injection holes is arranged near the front end of the combustion chamber 100, and the second group of injection holes is arranged in the middle of the combustion chamber 100.

[0042] The simulation experiment of the water ramjet engine with the blunt cavity powder inlet structure in the embodiment is finally obtained, and the flow field streamline diagram of the front end of the combustion chamber 100 is as shown in Figure 6 , and the particle trajectory diagram is as shown in Figure 7 .

[0043] Figure 6 In the figure, the No. 1 and No. 6 vortex areas are high-temperature gas vortex areas, the No. 3 and No. 4 vortex areas are powder particle vortex areas, and the No. 2 and No. 5 vortex areas are water vapor vortex areas.

[0044] It can be found from Figure 6 and Figure 7 that the presence of the conical cylinder-shaped blunt body 500 makes most of the particles complete the mixing and combustion with water vapor in the vortex area, and the high temperature generated by the propellant grain combustion makes the water droplets evaporate, and the coupling process of the powder particles and the water vapor mixing and combustion is self-sustaining, so as to realize the working process of the water ramjet engine combustion chamber 100. The front end flow field of the water ramjet engine combustion chamber 100 is mainly dominated by six vortexes, the interaction between the particles and the fluid is dominated by the drag force at low Reynolds number, and the particles tend to be on the interface between the vortexes under the coupling effect between the vortex structures. In the front end flow field of the combustion chamber 100, the pair of symmetric revolving vortexes of No. 3 and No. 4 is induced downstream by the powder inlet structure of the blunt body 500, the symmetric vortexes of No. 2 and No. 5 are induced by the water injection on the side wall, and the particles are mainly distributed on the interface between the No. 3-No. 2 and No. 4-No. 5 vortexes from Figure 7 . Therefore, most of the powder particles are completely combusted in the center of the combustion chamber 100 downstream of the blunt body 500 structure, and only a small amount of powder particles will be transported to the wall of the combustion chamber 100, so as to avoid the deposition of solid metal oxides generated by combustion on the wall of the combustion chamber 100 and the surface of the blunt body 500, which will destroy the flow field in the combustion chamber 100 or block the powder injection inlet.

[0045] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A water-jet engine with a blunt-body cavity powder inlet structure, characterized in that, include: Combustion chamber (100); A gas generator (200) is used to supply high-temperature gas to the combustion chamber (100), and the gas generator (200) is fixedly connected to the front end of the combustion chamber (100); A powder transport pipe (300) is fixedly installed inside the gas generator (200). The front end of the powder transport pipe (300) is connected to a powder supply device, and the rear end of the powder transport pipe (300) extends into the combustion chamber (100) from the air inlet at the front end of the combustion chamber (100). Tail nozzle (400), the tail nozzle (400) is fixedly connected to the rear end of the combustion chamber (100); A cone-shaped blunt body (500) is fixedly connected to the rear end of the powder transport pipe (300), and the opening of the blunt body (500) faces the tail nozzle (400).

2. The water-jet engine with a blunt-body cavity powder inlet structure according to claim 1, characterized in that, The axis of the blunt body (500) and the axis of the combustion chamber (100) are collinear.

3. The water-jet engine with a blunt-body cavity powder inlet structure according to claim 2, characterized in that, The angle between the generatrix and the axis of the blunt body (500) is 25°~60°.

4. The water-jet engine with a blunt-body cavity powder inlet structure according to claim 3, characterized in that, The gas generator (200) is provided with an annular sealing plate (210), an outer shell (220), an inner shell (230), an annular baffle plate (250), and an annular end-burning dual-base propellant column (260); Both the outer shell (220) and the inner shell (230) are cylindrical, and their axes coincide with the axis of the annular sealing plate (210). The outer shell (220) and the inner shell (230) are both fixedly connected to the side of the annular sealing plate (210) facing the combustion chamber (100). The inner shell (230) is disposed inside the outer shell (220). The shaft diameter of the inner shell (230) is less than or equal to half of the shaft diameter of the outer shell (220). The rear end of the outer casing (220) is fixedly connected to the front end of the combustion chamber (100) via a flange; The annular end-burning dual-base propellant column (260) is disposed in the annular cylindrical cavity formed between the outer shell (220) and the inner shell (230), and the annular baffle plate (250) is disposed behind the annular end-burning dual-base propellant column (260), with the outer sidewall of the annular baffle plate (250) abutting against the inner sidewall of the outer shell (220).

5. The water-jet engine with a blunt-body cavity powder inlet structure according to claim 4, characterized in that, The powder transport pipe (300) includes a throttling cone pipe section (310), a flow control pipe section (320) and a support pipe section (330) that are fixedly connected in sequence along the powder transport direction; The opening of the throttling cone section (310) faces the annular sealing plate (210), the opening of the throttling cone section (310) is in contact with the inner wall of the annular sealing plate (210), and the throttling cone section (310) is fixedly connected to the annular sealing plate (210). An adjustable ball valve (340) is fixedly mounted on the outside of the flow control pipe section (320) via a threaded joint; The outer wall of the support pipe section (330) is integrally connected with a support member (350). The support member (350) is annular columnar. The front end of the support member (350) is axially fixedly connected to the rear end of the inner shell (230). The outer diameter of the support member (350) is equal to the outer diameter of the inner shell (230). The annular baffle plate (250) is sleeved on the outside of the support member (350), and the annular baffle plate (250) is evenly provided with a plurality of gas passage holes (360).

6. The water-jet engine with a blunt-body cavity powder inlet structure according to claim 5, characterized in that, A direct-flow nozzle (370) is provided inside the end of the support tube section (330).

7. The water-jet engine with a blunt-body cavity powder inlet structure according to claim 4, characterized in that, The side wall of the combustion chamber (100) is provided with at least one injection hole for spraying water into the combustion chamber (100); Along the axial direction of the combustion chamber (100), the injection hole is located behind the blunt body (500).

8. The water-jet engine with a blunt-body cavity powder inlet structure according to claim 4, characterized in that, An annular heat insulation layer (240) is provided between the annular sealing plate (210) and the annular end-burning dual-base propellant column (260), and the annular heat insulation layer (240) is sleeved on the inner shell (230).

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