RU116912U1 - REACTIVE ENGINE DEVICE WITH VARIABLE TRACTION EFFICIENCIES - Google Patents

Abstract

The device of a jet engine with variable thrust, containing a fuel tank, four combustion chambers, four nozzles, as well as four fuel pumps and two superchargers with inlet guide vanes for the oxidizer - atmospheric air, characterized in that the oxidizer blowers are atmospheric air with inlet guide vanes are driven by a reciprocating internal combustion engine, and pipes extend from their bodies, expanding at the end to form cavities of combustion chambers, ending in a converging nozzle for flow exit, and the fuel pumps are driven by electric motors.

Description

The utility model relates to jet installations containing an engine other than a gas turbine, and which drives a supercharger and is intended for use on vehicles with vertical take-off and landing.

A device for a solid fuel rocket engine consisting of a combustion chamber and a jet nozzle is known.

The disadvantages of the device is the short duration of the traction force, as well as the impossibility of changing it. (see Yu.V. Kolesnikov // Children's Encyclopedia. - 1974. No. 5. P.155-159.)

A device is known for a turbojet engine developing thrust due to the reaction force (recoil force) of a jet of gases escaping from a nozzle, including: a compressor, a combustion chamber, a turbine and a nozzle. The compressor is designed to compress air and supply it to the combustion chamber. Fuel is injected into the combustion chamber under pressure and set on fire. The turbine rotates the compressor through the shaft.

The disadvantage of this device is the fragility of the turbine. (see L.V.Victorov // Children's Encyclopedia. - 1974, No. 5. P.70-73.)

The closest device of the same purpose to the claimed utility model in terms of features is a liquid-propellant engine device including combustion chambers in which fuel components, oxidizer pumps, fuel pumps, fuel and oxidizer, fuel tank, and output nozzles are fed into the chambers.

The disadvantages of the device is that in the known device there is a need to store the oxidizing agent necessary for the oxidation of fuel, which increases the mass of the engine by the mass of the oxidizing agent. (see Yu.V. Kolesnikov // Children's Encyclopedia. - 1974. No. 5. P.155-159.), taken as a prototype.

The problem to which the claimed utility model is directed is to create a jet engine device that is devoid of the above disadvantages, has long-term performance and which provides the ability to change traction by changing the fuel consumption supplied to the combustion chambers and high reliability, and there is no need for storage of oxidizing agent.

The specified technical result is achieved by the fact that in a variation of the known device of a jet engine, including a fuel tank, four combustion chambers, four nozzles, as well as four fuel pumps and two superchargers with inlet guide vanes for the oxidizer - atmospheric air are driven by a piston internal combustion engine , and from their bodies, pipes expanding in the final part exit for the formation of cavities of the combustion chambers ending in a tapering nozzle for the exit of the flow, and fuel pumps are driven by electric motors.

The figure schematically shows the structure of a jet engine with variable traction, a general view;

The device consists of a fuel tank 1, a piston internal combustion engine 2, a right supercharger with an input guide apparatus 3, a left supercharger with an input guide apparatus 4, four fuel pumps 5, four electric motors 6.

At constant revolutions of the internal combustion engine 2, at a constant pressure at the inlet of the superchargers with rotary inlet guide vanes 3 and 4, at a constant full pressure in the combustion chambers corresponding to the design mode of the superchargers with high efficiency and a certain air flow rate, as well as the flow exit nozzles in the design mode, when the flow expansion is carried out to atmospheric pressure and with a speed in the outlet section of the nozzle close to the speed of sound, an increase in the fuel supply to the combustion chambers The combustion process organized in them would lead to an increase in temperature, an increase in pressure, and a decrease in flow rate, due to a stronger expansion of gases due to an increase in temperature, and to the exit of a stream from nozzles with underexpansion, i.e. with a pressure higher than atmospheric, which makes it possible to return to the previous value of the air pressure in the combustion chamber, but with a higher temperature, and therefore to the previous value of the air flow, but not by reducing the engine speed, but by expanding the output section of the nozzle, having received at the same time, a decrease in the negative nozzle thrust arising due to the presence of pressure on the narrowing walls of the nozzle, and as a result, an increase in the engine thrust, while maintaining the rotational blowers with rotary input power guides.

This is shown by the following comparative thermodynamic calculation carried out for two engines with the same pressure in the combustion chamber, with the same air flow rate, but with different temperatures in the combustion chamber, under the assumption that the outflow of gases from the nozzles occurs at the Mach number (M = 1) and at atmospheric pressure, and the velocities in the combustion chamber are small and the Mach number (M≈0) can be taken in them, then:

In the combustion chamber for M≈0 from the formula (1):

P is the pressure in cross section with a certain number of M, Pa;

P ^* is the pressure in the critical section where M = 1, Pa;

k = 1.4 for air;

M is the Mach number;

we will have that the ratio of the pressure in the combustion chamber to the pressure in the critical section is:

P is the pressure in the cross section with the number M≈0 of the combustion chamber, Pa;

P ^* is the pressure in the critical section with the number M = 1, Pa;

From which it follows that if there is a pressure P ^* = 100000 Pa in the critical section adopted in the calculation, the pressure in the combustion chamber will be P = 190,000 Pa.

Also, with this number M = 0 from formula (3):

T is the temperature in cross section with the number M, ° K;

T ^* is the temperature in the critical section where M = 1, ° K;

k = 1.4 for air;

M is the Mach number;

the ratio of the temperature T ₁ = 1073 ° K adopted in the combustion chamber in the first case and T ₂ = 673 ° K in the second case to the temperature in the critical section at M = 0 is:

T is the temperature in the cross section with the number M≈0 of the combustion chamber, ° K;

T ^* is the temperature in the critical section with the number M = 1, ° K;

From which it follows that the temperature in the critical section will be in the first case: , and in the second case: .

From which it is possible to determine the density in the critical section in the first case, for T ₁ = 1073 ° K, the density in the combustion chamber:

- density in the critical section, kg / m ³ ;

- pressure in the critical section, Pa;

- gas constant for air;

and for T ₂ = 673 ° K in the second case:

- density in the critical section, kg / m ³ ;

- pressure in the critical section, Pa;

- gas constant for air;

The speed of sound in an adiabatically and isentropically inhibited gas in the first case will be:

- sound speed in adiabatically and isentropically inhibited gas, m / s;

k = 1.4 for air;

- gas constant for air;

- temperature in the critical section with the number M = 1, ° K;

and the velocity in the critical section is:

- velocity in the critical section, m / s;

k = 1.4 for air;

- sound speed in adiabatically and isentropically inhibited gas, m / s;

The speed of sound in an adiabatically and isentropically inhibited gas in the second case will be:

- sound speed in adiabatically and isentropically inhibited gas, m / s;

k = 1.4 for air;

- gas constant for air;

- temperature in the critical section with the number M = 1, ° K;

and the velocity in the critical section is:

- velocity in the critical section, m / s;

k = 1.4 for air;

- sound speed in adiabatically and isentropically inhibited gas, m / s;

Then the critical sectional area of the nozzle will be in the first case:

F ₁ - the critical section area of the nozzle, m ² ;

G - air flow, kg / s;

- density in the critical section, kg / m ³ ;

- velocity in the critical section, m / s;

Then the critical sectional area of the nozzle will be in the second case:

F ₂ - the critical section area of the nozzle, m ² ;

G - air flow, kg / s;

- density in the critical section, kg / m ³ ;

- velocity in the critical section, m / s;

Then the engine thrust in the first case will be at least:

G - air flow, kg / s;

- velocity in the critical section, m / s;

, and in the second case, the engine thrust will be no less than:

G - air flow, kg / s;

- velocity in the critical section, m / s;

It can be seen from this comparative calculation that both engine versions have the same air flow rates, the same pressure in the combustion chambers, but there is a difference in temperature in the combustion chambers, which is why the version with a higher temperature has a critical cross-sectional area, flow rate and draft are higher.

The device operates as follows.

The piston internal combustion engine 2 rotates the superchargers with rotary inlet guide vanes 3 and 4, which suck in atmospheric air, the fuel pumps 5 pump fuel from the fuel tank 1 into the combustion chambers, where combustion with the formation of combustion products is carried out, and they are released into the atmosphere through tapering nozzles.

By changing the amount of fuel entering the combustion chamber, by changing the speed of the electric motors 6 control the resulting traction. Changing the installation angle of the input rotary guide vanes, control the emerging torque.

Claims (1)

A variable-thrust jet engine device comprising a fuel tank, four combustion chambers, four nozzles, as well as four fuel pumps and two superchargers with inlet guide vanes for the oxidizer - atmospheric air, characterized in that the oxidizer blowers are atmospheric air with inlet guide vanes driven by a reciprocating internal combustion engine, and pipes extending in the final part to form the cavities of the combustion chambers exit from their bodies with a tapering nozzle for the exit of the stream, and the fuel pumps are driven by electric motors.