RU2608427C1 - Method of pulse jet engine double-flow blowing and double-flow pulse jet engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: method of pulse jet engine double-loop blowing consists in air supply through valve, its subsequent mixing with fuel and ignition. Pulse jet engine blowing at suction cycle is performed simultaneously via two circuits of different-type inlet valves, aerodynamic and mechanical, with subsequent arrangement of intensive mixing in combustion chamber by means of combustion zone jet blowing with formation of annular vortices. Besides, additionally performing blowing towards gas jet main flow from ejector prechamber, located at combustion chamber end wall. Double-flow pulse jet engine comprises combustion chamber, resonator pipe, inlet pipes, gas supply nozzle, gas heating coil and ignition plug. Combustion chamber front wall is made with mechanical lamellar valve. Combustion chamber rear end wall is made with ejector prechamber.

EFFECT: invention allows increasing thermodynamic efficiency by increasing pressure pulsations amplitude, occurring with increase in volume of combustion chamber cyclic blowing.

4 cl, 4 dwg

Description

The invention relates to equipment, mainly military, namely, aircraft engines, and can be used, most likely, in the engines of small unmanned aerial vehicles, such as, for example, unmanned reconnaissance aircraft, flying targets.

A known method of purging a pulsating jet engine (hereinafter PuVRD) of a German cruise missile of World War II Fau-1 (see GB Sinyarev, MV Dobrovolsky. Liquid rocket engines. - Oborongiz, 1957, p. 19, twenty). It is implemented through the use of one device - the valve grille. It is a structure of supporting elements - transverse rods, movable elements - flat elastic plates of constant thickness, attached to the side faces of the rods in pairs parallel to each other at a distance equal to the thickness of the rod, and support spacers placed in the middle between the pairs of plates parallel to them. In each pair between the plates there is a blind gap facing back. The plates and spacers form longitudinal channels for the passage of air.

The flow on the engine flows through the air intake and valve grille into the combustion chamber. Volatile fuel is supplied there, after which the air-fuel mixture is ignited by an electric spark. The combustion products rapidly expanding in all directions, getting into a dead gap between the plates, are inhibited, as a result of which the pressure increases there. This causes the plates to bend to the sides until they come in contact with the support spacers or side walls. The air channels of the valve grille are blocked. The combustion products flow through the nozzle into the atmosphere, and their pressure on the closed valve grill creates an impulse of engine thrust.

After the pressure drop, the valve plate plates under the action of their elasticity, as well as the rarefaction created in the chamber by the inertia of the outgoing gases, return to their original position. The next portion of air enters the chamber, and the cycle repeats.

The main advantage of the PuVRD purge method, based on the use of mechanical valve grids, is the high hydraulic resistance of the combustion products, trying to break through towards the oncoming flow during an explosion in the combustion chamber.

Their disadvantage is the high hydraulic resistance when purging the combustion chamber, especially at low flight speeds, which leads to low cyclic volumetric filling and, as a result, to low specific and frontal thrust. But the main thing is that they give a drop in thrust at high flight speeds due to mechanical bending by the dynamic pressure of the air of the valve petals, which leads to the transition to direct-flow PuVRD mode.

Also known is a method of purging PuVRD using aerodynamic valves, which are often used as simple tubes (Unsteady flame propagation. / Ed. By J. G. Markstein, M., Mir, 1968, pp. 401-407 (PROTOTYPE)). In addition, PuVRD, in which the replacement of mechanical valves by aerodynamic, described in US patent No. 2796735, 1957; No. 2796734, 1957; No. 2746529, 1956; No. 2822037, 1958; No. 2812635, 1957; No. 3093962, 1963.

The disadvantages of this method of purging PuVRD include the low amplitude of pressure pulsations in the combustion chamber and, accordingly, the low thermodynamic efficiency (efficiency) due to the low resistance of the aerodynamic valve to the emission of combustion products, especially at low flight speeds of up to 100 m / s. At higher flight speeds, in the event that the aerodynamic valve is turned towards the incoming flow, the hydraulic resistance to the reverse ejection increases with increasing speed, and the work improves significantly.

This process is shown for illustrative purposes in the graph below, which shows the nature of the dependence of the hydraulic resistance to the return emission of combustion products on the flight speed. It can be seen that in the speed range of up to 100 meters per second, the mechanical valve has a significantly greater inverse resistance (more than 30 times). But as the speed of the oncoming flow increases, its superiority decreases and at speeds of about 200 meters per second, this parameter closely approaches the aerodynamic valve turned towards the flow.

It is possible to increase specific and frontal thrust and lower specific fuel consumption by increasing the amplitude of pressure pulsations, which is achieved by increasing the volume of cyclic purge of the PuVRD combustion chamber, which directly depends on the inverse hydraulic resistance of the valve. An increase in the amplitude of the pulsations leads to an increase in the thermodynamic efficiency and, accordingly, to a decrease in the specific fuel consumption. Therefore, a natural technical solution is the combination of two methods of purging PuVRD, when it is purged simultaneously through two circuits of inlet valves - aerodynamic and mechanical. Joint purging through two valve circuits leads to a significant improvement in the speed characteristics of the PuVRD. PuVRD acquires a new quality - a progressive high-speed characteristic in a wide range of flight speeds, and at speeds above 150 m / s in terms of thrust and specific fuel consumption, it is two times higher than the similar PuVRD with mechanical valves. An example of such a characteristic is shown in the graph below. These data were obtained by the authors theoretically and experimentally.

The technical result achieved as a result of the implementation of the group of the proposed inventions is to increase the thermodynamic efficiency by increasing the amplitude of the pressure pulsations that occur with an increase in the volume of cyclic purging of the combustion chamber.

The technical problem is solved by organizing a double-circuit purge on the suction cycle through the flap mechanical valve and aerodynamic and the subsequent organization of intensive mixing in the combustion chamber by jet blowing the combustion zone through the profiled openings of the deflector of the mechanical valve, leading to the formation of ring vortices. This increases the rate of combustion and heat in the combustion chamber. Additionally, an increase in the burning rate is influenced by blowing towards the main stream of the gas stream from the prechamber located on the end wall of the combustion chamber.

The specified technical result in the implementation of the invention is achieved by the fact that in the known method of dual-circuit blowing a pulsating pulsed jet engine (PuVRD), which consists in supplying air through a valve, then mixing it with fuel and ignition, purging PuVRD on the suction cycle is carried out simultaneously through two different types of circuits inlet valves - aerodynamic and mechanical, followed by the organization of intensive mixing in the combustion chamber by jet blowing the combustion zone with azovaniem ring vortices. In addition, they additionally carry out blowing towards the main stream of a gas stream from the ejector prechamber located on the end wall of the combustion chamber.

In a known dual-circuit pulsating air-jet engine (PuVRD), containing, in particular, a combustion chamber, a resonator pipe, intake pipes, a gas supply nozzle, a gas heating coil and a spark plug, the front end wall of the combustion chamber is made with a mechanical flap valve, and the rear the end wall of the combustion chamber is made with an ejector prechamber. The mechanical flap valve is made with a deflector containing profiled holes.

Comparison of scientific, technical and patent documentation on the priority date in the main and related sections of the MKI shows that the set of essential features of the claimed solution was not previously known, therefore, it meets the patentability condition of “novelty”.

The analysis of known technical solutions in the art showed that the proposed device has features that are not available in the known technical solutions, and their use in the claimed combination of features makes it possible to obtain a new technical result, therefore, the proposed technical solution has an inventive step compared to the existing level technicians.

The proposed technical solution is industrially applicable, because can be manufactured industrially, efficiently, feasibly and reproducibly, therefore, meets the patentability condition “industrial applicability”.

Other features and advantages of the claimed invention will become apparent from the following detailed description, given solely in the form of a non-limiting example and with reference to the accompanying drawing, illustrating a preferred embodiment, which shows a diagram of the proposed PuVRD that implements a dual-circuit purge.

In FIG. 1 shows the inventive dual-circuit pulsating jet engine (PuVRD),

In FIG. 2 shows an ejector prechamber mounted on the rear end wall of the combustion chamber,

In FIG. 3 shows a mechanical flap valve mounted on the front end wall of the combustion chamber,

In FIG. 4 shows groups of annular vortices formed by elements of a mechanical flap valve.

The positions in the drawing show:

1 - gas supply nozzle,

2 - the first inlet pipe-mixer,

3 - second inlet pipe,

4 - combustion chamber,

5 - visor,

6 - rear end wall of the combustion chamber,

7 - resonator tube,

8 - glow plug

9 - gas heating coil,

10 - throttle,

11 - fuel tank (with liquid propane),

12 - gas line,

13 - mechanical flap valve

14 - elastic petal,

15 - chipper

16 - deflector,

17 - profiled holes,

18 - ejector prechamber,

19 is an internal mixer,

20 - holes

21 - gas pipe,

22 - zone of collision of jet streams,

23 is a group of annular vortices formed by elements of a mechanical flap valve,

24 - contour of the fuselage of the aircraft.

The dual-circuit pulsating PuVRD shown in the drawings contains a gas supply nozzle 1 with a first inlet pipe coaxially mounted by a mixer 2, a second inlet pipe 3, at the end of which a combustion chamber 4 with a visor 5 and a rear end wall 6 is fixed. To the rear end wall 6 of the chamber a combustion tube 4 is fixed to the resonator tube 7 with a spark plug 8. The gas heating coil 9 is connected via a throttle 10 to a fuel tank 11 in which liquid propane is located, and through a gas line 12 to a gas supply nozzle 1. On the front wall of the chambers combustion 4 fixed mechanical flap valve 13 with elastic petals 14 and chippers 15. Behind the mechanical flap valve 13 is fixed deflector 16 with profiled holes 17. The rear end wall of the combustion chamber 6 contains a rigidly mounted ejector chamber 18 with a tube of the internal mixer 19, perforated in front holes 20 and connected through a gas pipe 21 to the gas line 12.

When the inductor 10 is partially opened and a spark is supplied to the spark plug 8, gas ignites and burns inside the combustion chamber 4. After some time, the gas heating coil 9 and the walls of the combustion chamber 4 are heated and the further opening of the inductor 10 leads to the implementation of a double-pulsed pulsed air-exhaust air exhaust system. It is carried out as follows.

The gas supplied through the gas supply nozzle 1 ejects air into the first intake circuit - into the first inlet pipe-mixer 2 and the second inlet pipe 3, which also perform the function of an aerodynamic valve in the inventive double-circuit pulsating PuVRD. Next, the jet flow of the air-gas mixture, not reaching the rear end wall 6 of the combustion chamber 4, collides with the oncoming jet stream 22 of the high-temperature gas emitted by the ejector chamber 18. In the collision zone of the group of annular vortices 23 formed by the elements of the mechanical flap valve 13, initialization combustion, and the burning mixture then moves along the combustion chamber 4 into the resonator tube 7. Downstream, it meets a group of annular vortices 23 formed by profiled openings 17 the deflector 16 of the mechanical flap valve 13, which is the second air supply circuit. These annular vortices 23 are formed on the suction cycle when the combustion chamber 4 is purged through the open elastic lobes 14 of the mechanical flap valve 13. A group of air annular vortices 23 meet with high-temperature combustion products under conditions of intense mass transfer, which causes a sharp increase in pressure due to intensification of combustion. Further combustion occurs on the turns of the gas heating coil 9, which additionally performs the function of the “Shchelkin Spiral”, which turbulizes and accelerates combustion.

The described process corresponds to one phase of the duty cycle, namely the purge phase, followed by ignition and combustion. Next, the phase of ejection of combustion products through the resonator tube and partly through the valves takes place, and the cycle repeats. Cycling of the work is traditionally realized by tuning to resonance by changing the length of the inlet pipe-mixer 2, the length of the resonator pipe 7 and the geometry of the combustion chamber 4 with the second inlet pipe 3.

When installing a dual-circuit pulsating PuVRD on an aircraft, it is necessary that the second air supply circuit — a mechanical flap valve 13 — is in the aerodynamic shadow behind the fuselage of the aircraft 24, which ensures its operability in a wide range of flight speeds. The supply of additional air through the second circuit largely compensates for the lack of an aerodynamic valve in the primary circuit - its low hydraulic resistance to the emission of combustion products towards the flow during the work cycle. The increase in jet thrust at flight speeds of up to 100 m / s can reach 100%.

Of course, the invention is not limited to the described example of its implementation, shown in the attached drawing. It remains possible to change various elements or replace them with technical equivalents, not beyond the scope of the present invention.

Claims (4)

1. A method of dual-circuit purging of a pulsating air-jet engine (PuVRD), which consists in supplying air through a valve, then mixing it with fuel and igniting, characterized in that the purge of the PuVRD on the suction cycle is carried out simultaneously through two circuits of different types of inlet valves - aerodynamic and mechanical , followed by the organization of intensive mixing in the combustion chamber by jet blowing the combustion zone with the formation of ring vortices. 2. The method of dual-circuit purging of a pulsating air-jet engine (PuVRD) according to claim 1, characterized in that it is additionally carried out by blowing towards the main stream of a gas stream from the ejector chamber located on the end wall of the combustion chamber. 3. A dual-circuit pulsating air-jet engine (PuVRD), containing, in particular, a combustion chamber, a resonator pipe, inlet pipes, a gas supply nozzle, a gas heating coil and a spark plug, characterized in that the front end wall of the combustion chamber is made with a mechanical flap valve, and the rear end wall of the combustion chamber is made with an ejector prechamber. 4. A dual-circuit pulsating air-jet engine (PuVRD) according to claim 1, characterized in that the mechanical flap valve is made with a deflector containing profiled holes.

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