RU2324060C1 - Free-piston gas generator of ducted jet engine with two compressor-drive pistons - Google Patents

Abstract

FIELD: power-plant engineering.

SUBSTANCE: in free-piston gas generator of ducted jet engine air feed from the atmosphere into gas generator combustion chamber is carried out with the help of free-piston compressor. Compressor piston is placed in the middle of the stock with compressor drive pistons. They are brought into action by combustion products from gas generator combustion chamber.

EFFECT: improvement of specific mass and overall exponents of free-piston generator; efficiency upgrading.

1 dwg

Description

Technical field

The invention relates to the field of power engineering.

State of the art

The closest analogue of a ram engine with a free-piston gas generator is a gas turbine engine, see Belov P.M., Buryachko V.R., Akatov V.E., Engines of army vehicles. Part one. Theory. M., Military Publishing, 1971, pp. 475-487.

The principle of operation of a gas turbine engine. The compressor turbine draws air from the atmosphere and delivers it to the combustion chamber. There, fuel is injected and ignited, as a result of which the temperature of the gas stream rises. Further, the gas flow through the nozzle apparatus enters the blades of the compressor drive turbine, the rotation of which through the shaft is transmitted to the compressor turbine, thereby providing air from the atmosphere to the combustion chamber. After the compressor drive turbine, gases enter the nozzle apparatus of the traction turbine, creating a torque on its shaft. The main advantage of a gas turbine engine is the traction characteristic favorable for use as an automobile engine. The torque of the traction turbine at constant gas parameters is inversely proportional to the number of its revolutions. However, the low adiabatic coefficient of the fuel combustion process at low and medium speeds due to gas leakage between the periphery of the blades and the casing leads to an unacceptably high specific fuel consumption.

An object of the invention is to improve the specific mass and overall performance of the free piston generator and increase efficiency.

The problem is solved due to the fact that in a free-piston gas generator of a ram engine, air is supplied from the atmosphere to the combustion chamber of the gas generator by a free-piston compressor, the piston of which is located in the middle of the rod with compressor pistons located at the ends of the rod, driven by the combustion products from the combustion chamber of the generator gases.

The main difference between a ramjet engine with a free-piston gas generator and a gas turbine engine is that pistons play the role of blade turbines. The direct-flow engine consists of a freely piston gas generator and a traction expansion machine of a piston or turbine type. Since the innovation relates only to the free-piston gas generator, it is precisely its operating principle that is considered.

The composition of the free-piston gas generator (see drawing): 1 - combustion chamber, 2 - nozzle, 3 - spark plug, 4, 12 - gas distribution valves, 5, 8 - compressor drive pistons, 6 - rod, 7 - compressor piston, 9, 10, 11, 13, 14, 15, 16, 17 - air distribution valves, 18 - damper, 19 - distribution manifold.

The principle of operation of the free-piston gas generator

When the engine is started, fuel is injected into the combustion chamber 1 by the nozzle 2 and ignited by a candle 3. The combustion products through an open valve 4 enter the left cavity of the compressor drive piston 5, as a result of which the piston 5 and the compressor piston 7 and the compressor drive piston 8 connected to it by the piston 6 start moving from left to right. Air flows from the right-hand cavity of the piston 5 into the atmosphere through valve 9, the air from the atmosphere is sucked into the left-hand cavity of the piston 7 through the valve 10, and air is supplied from the right-hand cavity through the valve 11 to the combustion chamber 1, replenishing the oxygen flow rate during fuel combustion. An open valve 12 allows air to flow freely from the right cavity of the piston 8 without resisting the movement of the pistons. Air from the atmosphere is sucked into the left cavity of the piston 8 through the valve 13. When the pistons reach the neighborhoods of the extreme right position, the control system (not shown) puts the valves 4 and 12 to the right position and the gases from the combustion chamber through the opened valve 12 enter the right cavity of the piston 8, as a result of which the pistons stop and then begin to move from right to left. All other air distribution valves are in the opposite position. Exhaust gases from the left cavity of the piston 5 through the valve 4 open to the atmosphere, air from the atmosphere through the valve 14 is sucked into the right cavity of the piston 5, air from the left cavity of the piston 7 through valve 15 is fed into the combustion chamber 1, air from the atmosphere through the valve 16 is sucked into the right cavity of the piston 7, air from the left cavity of the piston 8 through the valve 17 is released into the atmosphere. simultaneously transferring heat from the piston 8. In the future, the control system, moving valves 4 and 12 from one extreme position to another, provides air to the combustion chamber. The pulsations of the air supplied to the combustion chamber are smoothed out by an air receiver (not shown). When the working pressure of the gases in the combustion chamber is reached, the shutter 18 opens and the generated gases through the distribution manifold 19 enter the traction expansion machine. The control of the current engine power is carried out by changing the intensity of fuel supply to the combustion chamber. The vibration resulting from the reaction from the movement of the pistons is compensated by the use of two gas generators arranged so that the axis of symmetry of the pistons are on one straight line, and the pistons move in antiphase.

The main advantages of a ram engine with a free-piston gas generator:

- traction characteristic favorable for use as an automobile engine - with constant gas parameters, the torque is inversely proportional to the number of shaft revolutions, which allows dispensing with the gear changing mechanism;

- the developed power is directly proportional to fuel consumption, that is, the efficiency is constant in the entire range of engine loads;

- straightforwardness and continuity of the workflow provides a sharp improvement in specific mass and overall indicators;

- in contrast to the classical ICE, less exactingness to the physicochemical characteristics of the fuel, multi-fuel;

- free-piston gas generator allows to realize a high degree of compression in the combustion chamber and an extremely high degree of expansion of gases in the traction machine;

- the use of heat-resistant materials will allow you to achieve a workflow with an excess air ratio close to unity - the closer it is to this value, the lower the relative energy consumption for compressor drive, the higher the efficiency of the engine as a whole;

- cooling of the walls of all cylinders, the distribution manifold and the combustion chamber by air flow from the compressor to the combustion chamber will allow for high-temperature cooling and eliminate the need for liquid cooling;

- the lack of liquid cooling provides high starting qualities and quick access to any power mode.

Claims (1)

A free-piston ram engine gas generator, characterized in that the air from the atmosphere is supplied to the gas generator combustion chamber by a free-piston compressor, the piston of which is located in the middle of the rod with compressor pistons located at the ends of the rod, driven by the combustion products from the combustion chamber of the gas generator.