RU2300005C2 - Pulsejet engine - Google Patents

Abstract

FIELD: mechanical engineering; engines.

SUBSTANCE: proposed pulse jet engine contains cylindrical combustion chamber, resonator tube, intake branch pipes, injector and spark plug. Intake branch pipes are located on cylindrical combustion chamber opposite to each other. Fuel is supplied through vortex prechamber in front part of combustion chamber.

EFFECT: increased thermodynamic efficiency by increasing amplitude of pressure fluctuations.

1 dwg

Description

The invention relates to equipment, mainly military, in particular to aircraft engines, and can be used, most likely, as the engine of small unmanned aerial vehicles, such as anti-aircraft, aviation and tactical missiles, unmanned reconnaissance vehicles, flying targets, etc. as well as resettable additional engines.

Known pulsating air-jet engine (hereinafter PuVRD) of the German cruise missile of World War II V-1 (see GB Sinyarev, MV Dobrovolsky. Liquid rocket engines. - Oborongiz, 1957, p.19, 20) . It is a channel of circular cross section open at both ends, including an inlet diffuser, a valve grill, a combustion chamber and an output device consisting of a confuser and an exhaust pipe, as well as a fuel supply system and an ignition system with an electric valve installed in the combustion chamber. In the General case, the input and output devices of the engine may have a form different from the prototype, so in the future we will call them accepted terms - the air intake and nozzle.

The valve grill 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 valve grill serves as the main, but not the only element of the assembly that creates thrust of a pulsating motor and also includes side walls, mounting parts, etc. In addition, other devices can also perform the thrust generation function in such an engine. Therefore, in the future we will use the general term "traction unit" (as part of the engine) and the specific one - the valve grille of the traction unit.

The advantages of PuVRD with mechanical valve grids are simplicity and low cost, low weight, reliability. Their disadvantage is poor traction characteristics, namely low specific and frontal thrust, high specific fuel consumption, impulse nature of traction, but most importantly - low valve life.

Also known are PuVRD designs using aerodynamic valves (Unsteady flame propagation. / Ed. By J.G. Markstein, M .: Mir, 1968, pp. 40-407). 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; 2812635, 1957.

The disadvantages of such high pressure air exhaust systems are the low amplitude of pressure pulsations and, accordingly, the low thermodynamic efficiency (efficiency).

It is possible to increase the specific and frontal thrust and reduce the specific fuel consumption by increasing the amplitude of pressure pulsations, which is achieved by increasing the rate of combustion of the fuel-air mixture in the combustion chamber of the PuVRD. An increase in the amplitude of pulsations leads to an increase in thermodynamic efficiency and, accordingly, to a decrease in specific fuel consumption.

The technical result of the invention is to increase the thermodynamic efficiency by increasing the amplitude of the pressure pulsations.

The stated technical problem is solved by intensifying the process of mass transfer in the combustion chamber, leading to an increase in the rate of quasi-detonation combustion and corresponding changes in the design of the PuVRD and its traction unit. At the same time, by “quasi-detonation” combustion is meant combustion with increased speeds of advancement of the flame front, which is 10-20 m / s in the case of air-propulsion. The organization of such a combustion regime occurs due to the intense mass transfer in the combustion chamber. The speed of the flame front is proportional to the speed of mass transfer.

The specified technical result during the implementation of the invention is achieved by the fact that in the well-known exhaust air exhaust system, containing, in particular, a cylindrical combustion chamber, a resonator tube, inlet pipes, a nozzle and a spark plug, the inlet pipes on the cylindrical combustion chamber are placed opposite, and the fuel is supplied through a vortex chamber in the front of the combustion chamber.

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 using them 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.

The positions in the drawing show:

1 - combustion chamber,

2 - resonator tube,

3 - vortex prechamber,

4 - nozzle

5 - inlet pipe of the vortex precamera,

6 - inlet pipes PuVRD,

7 - guiding devices,

8 - glow plug.

PuVRD, shown in the drawing, contains a combustion chamber 1 with a resonator tube 2 rigidly fixed to it. A cylindrical vortex pre-chamber 3 with a fuel nozzle 4 is made in the front part of the combustion chamber 1. An inlet pipe 5 of the vortex pre-chamber is installed tangentially to the chamber wall 3. On the wall of the combustion chamber 1, inlet pipes 6 PuVRD are opposite made, at the exit of which guide devices are installed 7. A glow plug 8 is fixed on the wall of the combustion chamber 1.

Inside the combustion chamber 1, when the spark plug 8 is triggered, an explosive (quasi-detonation) ignition of the fuel-air mixture occurs. At the same time, gas is ejected through the resonator pipe 2 and inlet pipes 5, 6 into the guiding devices 7, where it rotates 90 ° to create reactive thrust in the same direction with the resonator pipe 2. Further, as the pressure wave moves along the resonator pipe 2 a rarefaction is created in the combustion chamber 1 and air is introduced through the inlet pipes 5 and 6, and high-temperature combustion products enter from the resonator pipe 2. The oppositely directed inlet pipes 6 form oncoming jets of atmospheric air, which colliding in the medium of high-temperature combustion products entering from the resonator 2, provide a high level of turbulent mass transfer and, accordingly, a high “quasi-test” combustion rate, leading to an increase in the maximum cycle pressure and, accordingly, thermodynamic efficiency. The vortex prechamber 3 carries out preliminary gasification of liquid fuel, necessary for the combustion process to proceed at a high speed, and the formation of a precessing zone of reverse currents having a resonant frequency that coincides with the pulsation frequency of the PuVRD in the range of 150-200 Hz.

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 technically equivalent, not beyond the scope of the present invention

Claims (1)

A pulsed air-jet engine (PuVRD), comprising, in particular, a cylindrical combustion chamber, a resonator tube, inlet nozzles, a nozzle and a spark plug, characterized in that the inlet nozzles on the cylindrical combustion chamber are opposed and the fuel is supplied through the vortex chamber in front of the combustion chamber.