CN114991993B

CN114991993B - Self-excited detonation engine

Info

Publication number: CN114991993B
Application number: CN202210370146.XA
Authority: CN
Inventors: 陈玲; 陈科; 陈鸿; 陈道如
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-09-08
Filing date: 2022-04-08
Publication date: 2024-03-19
Anticipated expiration: 2042-04-08
Also published as: CN113803189A; CN114991993A

Abstract

A self-excited detonation engine mainly comprises an air inlet channel, a valve (with or without a valve), a detonation chamber, an exploder, a spray pipe, a fuel supply system, an ignition system, a cooling system, a control system and the like; the initiator mainly comprises a plurality of single hyperbolic grooves and/or other convergent grooves, and each groove corresponds to a reflection area of the inner wall of the engine body for focusing pressure waves by reflection of the grooves or converging by reflection; the single hyperbola refers to one of the hyperbolas; the inner wall of the machine body refers to the inner walls of the air inlet channel, the detonation chamber and the spray pipe; the pressure wave refers to an intake pressure wave, an atmospheric pressure wave returned from the rear end of the spray pipe or a high-temperature and high-pressure gas pressure wave. The technical scheme adopted by the invention is as follows: the detonation is achieved by reflective focusing or reflective convergence of the pressure wave by the recess of the initiator.

Description

Self-excited detonation engine

Technical Field

The invention relates to a self-excited detonation engine, which belongs to the category of pulse detonation engines and is a new concept engine based on detonation combustion.

Background

Since 1881 scientists discovered the knock phenomenon, the knock theory was gradually perfected and at the same time the concept of a knock engine was also developed in the application. The knock engine currently under investigation mainly has: pulse detonation engines, oblique detonation wave engines, and rotary detonation wave engines.

The pulse detonation engine is a new concept engine which utilizes high-temperature and high-pressure gas generated by pulse detonation waves to generate thrust. Detonation waves are supersonic (about 2000 m/s) combustion waves with their own compression function, detonation combustion approaches isovolumetric combustion, and thermal cycling efficiency (about 49%) is much higher than that of conventional engines (about 27%). The engine based on detonation combustion has the advantages of high combustion and energy release speed, high thermal cycle efficiency, low fuel consumption rate, simple structure, small volume, light weight, high thrust-weight ratio, large specific impulse and the like.

Although the detonation engine has a plurality of advantages, the problems of high-frequency detonation, working stability and the like are not substantially progressed mainly because of the technical deficiency and are still in the research and research stage at present. There are two types of current detonation schemes: direct detonation and indirect detonation, the direct detonation achieves detonation by high-voltage instant discharge, the detonation frequency is high, but very high energy (about 10 ⁵ Joules/second), is not repairable in applications; the indirect detonation realizes the detonation through the conversion from detonation to detonation (DDT), but the period from filling of fuel to the conversion from detonation to detonation of the DDT pipe is long, the detonation frequency is low (about 10 times/second), the detonation frequency is far less than the detonation frequency (about 100 times/second) of the detonation engine for generating the approximate continuous thrust, and both detonation schemes are not applicable, so the actual application cannot be realized, and the exploration of the applicable high-frequency detonation scheme is a key technology to be solved urgently at present.

Disclosure of Invention

A self-excited detonation engine mainly comprises an air inlet channel, a valve (with or without a valve), a detonation chamber, an exploder, a spray pipe, a fuel supply system, an ignition system, a cooling system, a control system and the like; the initiator mainly comprises a plurality of single hyperbolic grooves and/or other convergent grooves, and each groove corresponds to a reflection area of the inner wall of the engine body for focusing pressure waves by reflection of the grooves or converging by reflection; the single hyperbola refers to one of the hyperbolas; the inner wall of the machine body refers to the inner walls of the air inlet channel, the detonation chamber and the spray pipe; the pressure wave refers to an intake pressure wave, an atmospheric pressure wave returned from the rear end of the spray pipe or a high-temperature and high-pressure gas pressure wave.

The technical scheme adopted by the invention is as follows: the detonation is achieved by reflective focusing or reflective convergence of the pressure wave by the recess of the initiator.

Drawings

Fig. 1 and 2 are schematic diagrams of lateral structures of valved and valveless self-excited detonation engines, respectively.

Fig. 3 and 4 are schematic views of longitudinal structures of valved and valveless self-excited detonation engines, respectively.

FIG. 5, a schematic diagram of the output axial structure of a valveless rotary self-excited detonation engine (the engine is distributed circumferentially or in a spiral).

In the figure: 1-an air inlet pipe; 2-nozzle; 3-rotary valve (fig. 1, 3), diversion cone (fig. 2, 4, 5); 4-rotary valve inlet (fig. 1, 3), deflector ring (fig. 2, 4, 5); 5-thrust wall (fig. 1, 3 are planar thrust walls, fig. 2, 4, 5 are concave thrust walls); 6-thrust wall inlet port; 7-spark plugs; 8-detonators (fig. 3 and 4 are straight lines, the tail ends are turned into streamline shapes, and fig. 5 is an arc-shaped or spiral engine which is respectively distributed along the circumference or spiral); 9-initiator focus (fig. 1, 2), initiator focus along line (dotted line in fig. 3, 4, 5); 10-detonation tube; 11-spraying pipes; 12-an initiator cooling tube (inside and outside of the tube circulate in and out of the cooling liquid); 13-hyperbola (the inner focus of the left branch is located on the center of the inner wall section circle of the detonation tube 10, and the right branch is the curve where the right side groove section edge of the detonator 8 is located); 14-radial pressure waves; 15-a web; 16-output shaft.

Connection procedure (fig. 1, 3): the air inlet pipe 1 is connected with a detonation pipe 10; detonation tube 10 is connected with spray tube 11; the nozzle 2 is connected with the air inlet pipe 1; the rotary valve 3 is connected with the thrust wall 5; the thrust wall 5 is connected with a detonation tube 10; the spark plug 7 is connected with the knocking pipe 10; the initiator 8 is connected with the thrust wall 5; the detonator cooling tube 12 is coupled to the cooling system by a built-in tube of the thrust wall 5.

Connection procedure (fig. 2, 4, 5): the air inlet pipe 1 is connected with a detonation pipe 10; detonation tube 10 is connected with spray tube 11; the nozzle 2 is connected with the air inlet pipe 1; the diversion cone 3 is connected with the air inlet pipe 1; the guide ring 4 is connected with the detonation tube 10; the spark plug 7 is connected with the knocking pipe 10; the initiator 8 is connected with the thrust wall 5; the detonator cooling tube 12 is connected with a cooling system through a built-in tube of the guide cone 3; detonation tube 10 is coupled to web 15; the web 15 is coupled to an output shaft 16.

In the engines of fig. 1 and 2, the detonators with six and four single hyperbolic grooves are respectively illustrated, and the outer focus of each single hyperbola in the cross section of the groove is located on the center of the circular arc of the cross section of the inner wall of the detonation tube 10 corresponding to the Shan Zhishuang curve, so that the radial pressure wave 14 reflected by the corresponding circular arc is converged to the inner focus of the single hyperbola after being reflected by the single hyperbola. Assuming that the radius of the inner wall of the detonation tube 10 is r and the real axial length of the hyperbola 13 is 2a, the path length of the radial pressure wave 14 reflected by a single hyperbola to the inner focus is r-2a.

The outer focuses of the single hyperbolas in the plane circle are all positioned at the circle center and are distributed and connected along the circumference to form a curved edge, and the curved edge translates along the direction perpendicular to the plane to form a geometric body which is a linear single hyperbolic groove initiator. The straight single hyperbolic groove and the radial pressure wave and the converging spherical wave reflected by the inner wall of the corresponding machine body have the property of reflection and focusing; the radial pressure wave reflected by the inner wall of the corresponding machine body and the arc-shaped or spiral single hyperbolic groove have the property of reflection focusing.

Detailed Description

The working cycle of the engine in fig. 3 comprises four basic processes of air intake, detonation, combustion (detonation wave propagation) and exhaust.

1. And (3) air inlet: firstly, the rotary valve is opened, compressed air is driven into the air inlet pipe, then the nozzle injects fuel and mixes the fuel with air in the air inlet pipe to enter the knocking chamber, and when a proper amount of mixed gas is entered, the rotary valve is closed.

2. And (3) detonating: when the rotary valve is closed, the spark plug ignites the mixed gas, part of the mixed gas is exploded to generate high-temperature and high-pressure fuel gas, radial centripetal pressure waves and converging spherical pressure waves of the high-temperature and high-pressure fuel gas are reflected and focused by the grooves of the exploder, radial centrifugal pressure waves and diverging spherical pressure waves of the high-temperature and high-pressure fuel gas are reflected and focused by the inner wall of the engine body to the grooves of the exploder, and then the pressure and the temperature of the local mixed gas on the line in the grooves are rapidly increased by the reflection and the focusing of the grooves, so that the mixed gas is excited to knock and burn, and explosion waves are generated.

3. And (3) burning: the detonation wave generated by detonation propagates to the periphery at supersonic speed (about several kilometers per second), and the mixed gas generates a severe chemical reaction at the position where the detonation wave passes, and simultaneously the pressure and the temperature of the post detonation product are increased sharply (the pressure can reach 100 atmospheres and the temperature can reach 2000 ℃), along with high-speed energy release; the expansion pressure of detonation products in the detonation wave propagation process further promotes the detonation wave to continue to propagate to the periphery until the detonation of all the mixed gas is finished, and the detonation wave is discharged out of the detonation chamber.

4. And (3) exhausting: after the detonation wave is discharged, detonation products (high-temperature and high-pressure fuel gas) are sprayed out from a spray pipe (hereinafter referred to as exhaust), and reaction thrust is generated at the same time, so that heat energy is converted into mechanical energy.

In the exhaust process, the detonation chamber is in a vacuum state for a short time under the inertia effect of the gas flow, at the moment, the rotary valve is opened, the mixed gas in the gas inlet pipe automatically enters the detonation chamber under the effect of pressure difference, when a proper amount of mixed gas is entered, the rotary valve is closed at proper time, and then the last working cycle process of detonation, combustion and exhaust is entered; the engine is operated continuously from time to time.

The basic working cycle process of the engine in fig. 4 and 5 is the same as that in fig. 3, and the working cycle process of auxiliary air intake and automatic air intake, detonation, combustion and exhaust of the engine by exhausting and vacuumizing is required to start working, except that no mechanical valve is provided, and the fluctuation of the pressure in the annular air inlet channel plays a role of an aerodynamic valve. The engine of fig. 5 begins to operate by starting engine rotation to intake air and by exhausting air to propel the engine rotation and output mechanical energy outward.

The engine is detonated by reflecting and focusing the high-temperature and high-pressure fuel gas pressure waves in the engine body through the grooves of the detonators, and in addition, the detonation can be realized by reflecting and focusing other pressure waves in the engine body through the grooves of the detonators.

And (3) pressure-entering detonation: the engines in fig. 3, fig. 4 and fig. 5 generate high-intensity turbulence by high-speed air intake in the working process, and pressure waves generated by high-intensity turbulence pulsation can be reflected and focused through the grooves of the detonators, reflected to the grooves of the detonators through the inner walls of the engine body, and reflected and focused through the grooves to achieve detonation.

Back pressure detonating: when the engine in fig. 3, fig. 4 and fig. 5 is exhausted, the gas flow sprayed by inertia makes the spray pipe form a vacuum state, so that the atmospheric pressure wave at the rear end of the spray pipe returns to the detonation chamber, after being reflected by the thrust wall, the reflected wave and the incident wave are combined into a pressure wave with larger amplitude, and the pressure wave is reflected and focused by the groove of the initiator, reflected to the groove of the initiator by the inner wall of the engine body and reflected and focused by the groove, so that the detonation can be realized.

Spontaneous combustion initiation: in the engines of fig. 3, fig. 4 and fig. 5, the detonation can be realized by the reflection focusing of the high-temperature and high-pressure gas pressure wave through the groove of the initiator, the reflection focusing of the high-temperature and high-pressure gas pressure wave through the inner wall of the engine body to the groove of the initiator and the reflection focusing of the groove.

The implementation process of the single hyperbolic groove initiator for implementing the detonation on radial centripetal pressure wave and converging spherical pressure wave reflection and focusing is explained above. Single piece hyperbolic fluted detonators have a number of advantages: (1) the mixture gas is smoothly filled along the focal point; (2) The space in the exploder is convenient for arranging the cooling device, the cooling effect is good, and the problem that the mixed gas is spontaneously ignited in advance when the pressure wave arrives due to the overhigh wall temperature at the bottom of the groove is fully solved; (3) The pressure and the temperature of the mixed gas on the focal point along the line are greatly increased through the reflection focusing of the grooves; (4) facilitating the provision of an initiator having a plurality of recesses; therefore, the single hyperbolic groove initiator can greatly improve the success rate of initiation and has high practicability.

In addition, because of the disorder of the turbulence, the turbulence pulsation generates pressure waves of various wave systems, and the detonators of corresponding convergent grooves can be used for reflecting and focusing or reflecting and converging the pressure waves of each wave system to detonate; if the detonators with parabolic grooves are adopted for the pressure waves of the parallel wave system, the detonators with smooth curved grooves such as corresponding elliptic curved grooves, sinusoidal grooves and the like are respectively adopted for the pressure waves of different divergent wave systems.

The pulse jet engine forms a karman vortex street phenomenon in the air inlet process, and the alternating release of vortex in the vortex street enables a high-pressure area and a low-pressure area in the engine body to coexist simultaneously, and pressure amplification of reflection focusing of high-pressure waves and low-pressure waves through the inner wall of the engine body is small, so that the pulse jet engine can not reach the condition of high-pressure detonation, can only organize combustion based on a deflagration mode, and has low deflagration pressure (about 3 atmospheres), high fuel consumption rate, low working frequency (about 50 times/second) and large vibration.

In view of the problem that the pressure focused by the pulse jet engine on pressure wave reflection cannot reach the high-pressure detonation condition, the invention adopts the scheme of zonal reflection focusing to block the reduction of low-pressure waves on high-pressure waves, so that the pressure waves which are centripetally propagated in the high-pressure zone are reflected and focused by the grooves of the detonators, and the pressure waves which are centrifugally propagated in the high-pressure zone are reflected to the grooves of the detonators by the inner walls of the engine body and are reflected and focused by the grooves, and further, the pressure of local mixed gas on the line at the focus point in the grooves is greatly increased to realize detonation.

The detonation pressure of the detonation engine is about 30 times of the detonation pressure of the pulse jet engine, so that the detonation engine has high vacuum degree through exhaust vacuum pumping, large pressure difference between a detonation chamber and an air inlet channel and high air inlet flow rate; the propagation speed of the detonation wave is about 100 times that of the detonation wave, and thus it is presumed that the operation frequency of a self-excited detonation engine of the present invention is about several thousands of times/second, and that the continuity and stability of the generated thrust force can exceed those of the present various engines that organize combustion based on the detonation manner.

In conclusion, the self-excited detonation engine provided by the invention can automatically detonate at high frequency, is stable and reliable in operation, has the advantages of high combustion and energy release speed, high thermal cycle efficiency, low fuel consumption rate and the like, and has wide application prospects in various fields in the future.

Claims

1. The utility model provides a self-excitation detonation engine, mainly comprises intake duct, valve, detonation chamber, detonator, spray tube and fuel feed system, ignition system, cooling system and control system, its characterized in that: the initiator mainly comprises a plurality of single hyperbolic grooves and/or other convergent grooves, each groove corresponds to a reflection area of the inner wall of the engine body for pressure wave reflection focusing or reflection converging through the grooves, and the initiator realizes the initiation through the reflection focusing or reflection converging of the grooves for pressure wave.

2. The self-exciting knocking engine of claim 1, wherein: the initiator is arranged along the central axis direction of the inner wall of the machine body, and the inner wall of the machine body refers to the inner wall of the air inlet channel, the detonation chamber and the spray pipe.

3. The self-exciting knocking engine of claim 1, wherein: the convergent groove is a smooth curved groove with two sides converging towards one point.

4. The self-exciting knocking engine of claim 1, wherein: the pressure wave comprises an air inlet pressure wave, an atmospheric pressure wave returned by the rear end of the spray pipe or a high-temperature and high-pressure fuel gas pressure wave.

5. The self-exciting knocking engine of claim 1, wherein: the valve comprises a valved type or a valveless type.