CN102288070A - Gas-delayed recoiling method - Google Patents

Abstract

The invention relates to a gas-delayed recoiling method. The gas-delayed recoiling method is applied to making weapons with any apertures, gun-pressures and initial speeds realize emission with low recoiling force or no recoiling force, and can be also applied to fuel turbine engines, ramjet engines and rocket engines. A working medium as a branch system of a combustion chamber is converted from a constant-pressure combustion mode to a constant-volume combustion mode with higher thermal circulation efficiency. A piston is arranged in a body tube (namely a gun tube or a cannon tube) of a weapon, and the piston is simultaneously pushed to move in the direction of an axial line when gunpowder gas in the tube body is combusted and expanded to do work to emit a bullet; when a gun-pressure-time curve of the tube body is the constant, the special structure design of the piston makes the bullet just move to the position of a ventilating hole arranged on the body tube at the moment of the bullet emitted out of the gun chamber, thus a part of gunpowder gas is sprayed forwards along with the bullet, and a part of gunpowder gas is sprayed backwards through the ventilating hole so as to form a recoiling functional force to deduct the recoiling momentum of the body tube.

Description

Gas delayed blowback method

Technical field:

The method is applied to:

1. utilize powder gases in airtight barrel, burn, the expand various weapons with pipes system of acting emission bullet.The opposite direction to the bullet motion after the emission bullet sprays therefore formation reduce even offset barrel to the active force of barrel recoil at a high speed thereby main purpose is to make powder gases.Use this principle and can make the inverse recoil system of weapon have high efficient, to such an extent as to can make the weapon of any bore, gun pressure and initial velocity can realize low recoil or Recoilless emission.The weapons with pipes system comprises: the tube artillery of various rifles such as pistol, rifle, machine gun and various bores.

2. gas-turbine unit, punching engine and rocket engine.As the combustion chamber subsystem, make working medium change constant volume burning pattern into, finish conveying, burning, expansion (perhaps directly utilizing pressure) acting, the cyclic process of conveying again of working medium in the mode of pulsed operation with higher efficiency of cycle from the constant pressure combustion pattern.This has comprised pulse-jet motor, inferior combustion and scramjet engine, liquid and solid propellant rocket, turbojet, turboshaft engine and gas turbine, and the engine such as the rotary punching rotary engine of mixing class.The engine of using this principle can be referred to as: the constant volume burning pulsed motor.

Background technology:

The recoil that produces when launching for the balance weapon has various inverse recoil system.These systems are based upon on two kinds of basic principles basically: thus a kind of be the momentum of when launching bullet forward, launching certain object balance bullet with powder gases backward, practical mode is to make the ejection backward at a high speed when emission of part powder gases, i.e. the recoil of gas makes weapon be subjected to active force to reduce the recoil of weapon; A kind of be utilize machinery and hydraulic pressure (perhaps air pressure) thus mechanism time of prolonging the stroke increase recoil in recoil under the certain prerequisite of recoil momentum, recoil is reduced.The former is better than that latter's part is to make the quality of inverse recoil system lighter, volume is littler, does not need to be subjected to the restriction of recoil stroke, so weapon can be lighter to increase mobility.

With regard to preceding a kind of principle, existing two kinds of main application modes: recoilless gun and thorax mouth muzzle brake.The former emission during bullet powder gases spray at a high speed so that the momentum of bullet is all offset from afterbody, the latter be bullet go out after effect period powder gases after the thorax have part forward ejection and have in addition part under the muzzle brake effect backward at a high speed ejection make powder gases itself momentum by partial offset thereby reduced the recoil of the energy of after effect period powder gases to the barrel generation.In addition, the mixing operational mode that also has some to reduce recoil such as the anti-equipment sniping gun of some heavy calibers, has the part powder gases to spray backward by the gas operated device on the gun barrel in powder gases emission bullet, thereby can the partial offset recoil.

The advantage of recoilless gun is to reduce even to offset recoil to greatest extent; Shortcoming is powder gases i.e. ejection under imperfect combustion situation, the speed of the low therefore powder gases of temperature and pressure recoil is little, momentum is little and make that the efficient of inverse recoil system is low excessively, simultaneously if then powder gases ejection speed is high and make the gunpowder energy that is used to launch bullet reduce and reduce initial velocity and thorax mouth kinetic energy for the rising gun pressure, therefore cause the gun pressure of weapon and muzzle velocity to be restricted, simultaneously backward the powder gases of ejection burn away make the weapon emission characteristic obviously and shock wave and superpressure injure the bolter easily.

The advantage of thorax mouth muzzle brake is to promote powder gases completing combustion and makes the ejection backward at a high speed of completing combustion gas afterwards, the efficient of inverse recoil is than higher, and also make emission characteristic not resemble recoilless gun simultaneously because of the powder gases completing combustion of ejection so obvious; Shortcoming is partly to reduce forward the powder gases of ejection, and Pen Chu powder gases is limited thereby can't utilize the recoil of (recoil) momentum balance barrel of powder gases only to the momentum of gun barrel with (the bullet transmit direction) momentum that reduces powder gases itself and powder gases backward.

It is evident that, if the powder gases that can make completing combustion bullet go out thorax moment major part to ejection at a high speed in the other direction, the momentum that then not only can reduce or offset the gas that sprays forward also can be used for the momentum of balance bullet.Briefly, be exactly to possess the advantage of recoilless gun and thorax mouth muzzle brake simultaneously and avoid this both shortcoming.Such inverse recoil system possesses the highest efficient and classic tactical qualities.

Realize such purpose, need on weapon, dispose by " switch ", powder gases is completing combustion and " open " this switch in the moment that bullet goes out thorax in airtight barrel before bullet goes out thorax, so just can control and distribute the flow of powder gases that the powder gases of part (normally most of) completing combustion of needs is sprayed at a high speed to the opposite direction of bullet emission.Because the existence of this switch, powder gases ejection backward by " delays ", thereby claim that this principle is " a gas delayed blowback " for recoilless gun.Saying of image makes the gas " temporarily " that originally just should spray backward in the emission bullet rest on exactly (to burn away) in the barrel and is released in the moment that bullet goes out thorax.For thorax mouth muzzle brake, be equivalent to make more powder gases to change the direction of motion and " recoil " backward, and this part powder gases of script spray forward with bullet.

This principle realizes by the piston mechanism that is configured on the weapon barrel, " switch " function of promptly utilizing the motion of piston to realize.

Because the core of this principle is " delay ", be the expansion acting and the combustion process and asynchronous of powder gases, therefore can be applied to is gas-turbine unit, punching engine and the rocket engine that utilizes high temperature and high pressure gas to expand and do work equally, change the synchronism of burning and expansion acting so that just begin the acting of expanding after the fuel completing combustion, originally the constant pressure combustion pattern that adopts is improved to the constant volume burning pattern, thereby the higher efficiency of cycle, higher energy and bigger power are provided.

Summary of the invention:

When being applied to armament systems:

Piston of assembling in the barrel (being gun barrel or gun tube) of weapon when powder gases burning in the barrel, when expanding acting emission bullet, promotes piston simultaneously and moves along axis direction; When " gun pressure-time graph " of barrel certain, the position of the steam vent that the special structural design of piston makes the moment piston that goes out thorax at bullet can move on the barrel just to be opened, so, Yi Bufen powder gases sprays forward along with bullet and the powder gases of a part sprays backward by this steam vent and forms the recoil active force to reduce barrel recoil momentum.

In order to obtain bigger recoil energy, better way is " cylinder " that barrel (being gun barrel or gun tube) at weapon is gone up the tubulose of a powder gases that holds to be used to recoil of fixing assembling, for convenience of description for the purpose of below all be example with the gun barrel; Also can be set to any angle and as long as guarantee that the direction of emission direction that the interior powder gases of cylinder is final and required inverse recoil is identical but usually this cylinder and gun tube axis are parallel; (normally in close cartridge chamber part) offers gas port on the gun barrel, cylinder has gas port too at correspondence position, and the imperfect combustion powder gases of a part (be actually the compounding substances of powder gases and powder grain and only be called powder gases for simplicity) enters cylinder by gas port; The part powder gases is stayed the gun barrel internal combustion, the acting emission bullet that expands, meanwhile other part powder gases constant volume burning in cylinder; The cylinder front portion has steam vent, and piston mechanism is set herein, piston in cylinder closed grate hole when initial position is airtight with the maintenance cylinder, powder gases promotes the piston motion when cylinder combustion is burnt, after piston moves a segment distance, piston end surface this steam vent when the steam vent is opened, so powder gases can spray; Steam vent place assembling change gas flow direction jet pipe so that powder gases spray at a high speed to the direction of needs; Piston mechanism (piston can in gun barrel or in the cylinder) also is set as switch in the gas port position, the total amount that enters the powder gases of cylinder from gun barrel can be controlled, and avoided after bullet goes out thorax and opens steam vent, having powder gases in the partial cylinders to pass back into gun barrel causing energy loss by gas port.

The gas port position is near cartridge chamber, and then action time is longer and can make more that imperfect combustion powder gases enters in the cylinder because the gun barrel internal pressure is high more, so can obtain the momentum of bigger inverse recoil; Then gun barrel internal pressure low more action time shortlyer then enter powder gases in the cylinder more less and comparatively speaking more abundant remaining impetus of burning is littler near the thorax mouth, the momentum of the inverse recoil that then obtains is just more little.Set the size of inverse recoil momentum according to the inverse recoil momentum of weapon needs and the restriction of utilization condition, thereby determine the position of gas port.

The size of each stress surface of the gunpowder energy in the move distance of piston and the cylinder, the volume of cylinder and piston itself is relevant, under the certain prerequisite of the total energy of gunpowder, gas port size, volume of cylinder, " pressure-time graph " in the cylinder is certain thereby certain to the total pressure and the action time of piston, therefore only need the area of the different stress surfaces of flexible design piston just can determine speed, the distance that piston moves, thereby the time that can determine to open steam vent; Launch time is certain in gun barrel under the total energy of bullet, barrel length, gunpowder, the gas port size is certain, muzzle velocity the is certain prerequisite, therefore to be designed to go out with bullet time of thorax consistent when the time that open steam vent, just can realize the purpose of " delayed blowback ".

The muzzle velocity of weapon is certain, need under the certain situation of the inverse recoil system effectiveness that realizes, and the momentum (or momentum) of the powder gases recoil in the cylinder that then needs to realize is certain; And hypothesis is taken all factors into consideration factor such as the material property, cost, operational environment of gun barrel and jet pipe and can set highest pressure, nozzle efficiency and recoil in the cylinder the direction angle of gun tube axis (promptly with) and thereby the speed of definite powder gases recoil, then can therefore determine and need enter the quality of powder gases of cylinder and the volume of cylinder from gun barrel; " gun pressure-time graph " is known in the gun barrel, then decides the quality and the energy of (imperfect combustion) powder gases that enters cylinder by the area of design gas port; Therefore, can make the powder gases of delayed blowback provide in various degree active force as required with the recoil of balance weapon.

Why piston can be realized movement velocity needed, that can control, be because powder gases can be regarded as that homogeneous (uniform) fluid, each several part pressure equate thereby make powder gases to the force direction of the different end face of the piston area difference of each end face on the contrary mutually by design, then finally make the useful effect power minimum of piston motion can be zero product that is the pressure of the area of largest end face of piston and powder gases to the maximum.Here, the situations such as pressure anomaly that pressure wave that thorax is interior and cylinder is interior and variable cross-section or detonation produce have been ignored, and gas is reduced to isotropic homogeneous fluid so that utilize Mathematical Modeling to reflect the process of its burning and acting, and by experiment result of calculation is revised.

Advantage of the present invention:

1. existing all weapons with pipes can assemble easily, are not subjected to effects limit such as the gun pressure of weapon and initial velocity.In other words, existing weapons or redesign be can reequip and the low recoil of weapon or the Recoilless emission of any gun pressure and initial velocity realized.

2. reduce the quality and the volume of recoil, recoil stroke and the Recoil system of existing weapons greatly, reduce weapon manufacturing cost and manufacture difficulty, improve weapon production capacity.

3. because of the 2nd mobility that can improve weapon greatly.For example, the tactics truck that load-carrying is 2 tons can only be as the motor-driven flat pad of large-bore machine gun and the cannon below the 30mm under the prior art condition, uses the present invention and then can make it become the motor-driven flat pad-antitank fighting car of 105mm (perhaps more heavy caliber) antitank gun; Existing 155mm self-propelled gun weapon weight surpasses 40 tons mostly, uses the present invention and then can use light-duty wheeled vehicle as motor-driven flat pad, and so the gross weight of 155mm self-propelled gun weapon can be lower than 10 tons.In like manner, take-off weight 6-10 tonne of other helicopter can be used as the airborne flat pad of 105mm-125mm tank gun.

4. reducing significantly thereby can make the power of the small arms of hand-held and fire from the shoulder obtain to improve greatly, improve the stability and the precision of shooting because of recoil.When being used to improve the weapon power, can make existing large-bore machine gun and 20-40mm cannon can support the motor-driven emission of shoulder.

5. technological adaptability is strong.Development along with REGENERATIVE LIQUID PROPELLANT GUNS and electrothermal chemical gun technology, the initial velocity of weapon will significantly improve and recoil also will increase on an equal basis, if then construction weight and size increase several times even can can't operate above the restriction of weapon operation environment in the inverse recoil system that adopts machinery and hydraulic pressure; And that utilization the present invention adds all the better is favourable, because the raising that the momentum of the higher then inverse recoil of the recoil speed system of powder gases also can be directly proportional with it, thereby does not need to change the inverse recoil that construction weight and size just can realize equal efficient.

Shortcoming of the present invention:

1. need powder gases that the recoil of energy with the balance weapon is provided, therefore if the repacking existing weapons then when the higher inverse recoil efficient of needs (require inefficient situation is next not to be existed) can cause muzzle velocity to descend, reduce the weapon power; The technical performance (initial velocity and thorax mouth kinetic energy) that redesigns weapon and keep former weapon according to the present invention then for former weapon needs increase combustion chamber volume to hold more gunpowder required to satisfy the powder gases recoil, so the burning velocity of the total amount of the size of cartridge chamber part and structure, gunpowder and packaged type, gunpowder etc. all needs redesign.

2. (require inefficient situation is next not to be existed) increased the gunpowder total amount thereby improved cost for original ammunition when the higher inverse recoil efficient of needs; Increased parts such as cylinder and piston mechanism, thereby if former weapon do not have the inverse recoil system then cost must increase.

3. because powder grain sprays into cylinder at a high speed, can cause powder grain cracked and accelerated combustion even detonation, cause the inner pressure of air cylinder fluctuation and impact, influence mechanical performance, the life-span of weapon; The powder grain volume is big more obvious more.

4. the fire flexibility of weapon reduces.Be that same weapon is when launching the ammunition of different gun pressures, initial velocity, because the performance of gas port, volume of cylinder, piston mechanism etc. all immobilizes, therefore may cause the efficient of inverse recoil to change even make inverse recoil thrashing, thereby the recoil of weapon and stability also can change; The efficient of inverse recoil is constant then to need to make ammunition performance to satisfy the needs of inverse recoil if will keep, and promptly part bullet kind needs the performance of sacrificial section inner trajectory and outer trajectory, and if will keep this performance constant, has then increased the design and the manufacture difficulty of weapon.

5. because the recoil of powder gases, the shock wave of launching site, superpressure are strengthened with recoil efficient and weapon power, cause influence even injury, and make emission characteristic obviously and relatively be easier to expose launching site, also can increase requirement operational environment to weapon and launching crew.

When being applied to gas-turbine unit, punching engine and rocket engine (constant volume burning pulsed motor):

With inferior burning ramjet is example, come from supersonic inlet, flow to into the combustion chamber through the subsonic air of overcompression, inject fuel and produce burning, and lucky owing to the exhaust outlet of combustion chamber is opened in the motion of piston after fuel completing combustion, high temperature and high pressure gas is accelerated to supersonic speed by exhaust outlet and in convergent divergent nozzle and sprays; Before this, the method of closing air admission hole in (employing cylinder and air inlet and two piston mechanisms of exhaust) armament systems with the piston of using is similar, and another piston is promptly closed air inlet rapidly owing to the pressure effect of burning indoor gas at the initial stage (before perhaps taking fire) of burning, closed chamber makes the fuel constant volume burning.

When being applied to scramjet engine, discharge by bypass passageways by other part by air inlet introducing combustion chamber for the supersonic airstream part of HTHP in the supersonic inlet; The supersonic airstream of introducing enters combustion chamber volume expansion, temperature and speed to be reduced, and too much air causes the air pressure in the combustion chamber and temperature is too high lost efficacy burning to avoid introducing can need to close air inlet according to design under the gas pressure effect in the pressure of the supersonic airstream in air intake duct or the combustion chamber simultaneously; So equal the supersonic airstream of the high temperature in the original air intake duct is changed into the subsonic flow of low temperature, and constant volume burning in the combustion chamber; Have only after fuel completing combustion, could produce enough opened by pressure exhaust outlets, perhaps the waste gas of rich fuel is introduced supersonic combustor so that its smooth combustion under supersonic flow to discharge HTHP waste gas; Fuel can have time enough completing combustion, does not have direct relation with conditions such as air intake duct geometrical property and variation, supersonic speed shock-wave spot and variation thereof, intake velocity, fuel combustion speed and in the design of fundamentally only depending on the piston that is used for the switch pair gas port; Equally, the temperature of waste gas and rate of discharge and air intake duct length, intake velocity, fuel combustion speed etc. do not have direct relation, can make waste gas have suitable temperature and pressure so that best deflation rate and propulsive efficiency to be provided as required; If the air intake duct geometry is for fixing, the change of gas velocity, temperature and pressure can directly not influence burning and acting process in the air intake duct under different flying speeds, and only directly related with combustion chamber working pulse frequency, promptly change thrust size but do not influence engine operate as normal (so this advantage be particularly conducive to the rotary punching rotary engine make it possess stability and the output of the high power under the high operating mode under the low operating mode).

With gas-turbine unit (comprising turbojet, turboshaft engine and gas turbine) is example, the compressed air that compressor produces enters the combustion chamber by air inlet with subsonic speed, inject fuel and produce burning, lucky owing to the exhaust outlet of combustion chamber is opened in the motion of piston after fuel completing combustion, high temperature and high pressure gas is accelerated to supersonic speed by exhaust outlet and in convergent divergent nozzle and sprays, and the gas of ejection acts on high pressure (and low pressure) turbine at a high speed; If adopt special thermal power structure such as pressure disc or pneumatic wave rotor then can make high temperature and high pressure gas directly act on dynamical element undesirable gas after expansion just acting therefore the thermal efficiency to compare turbine higher; Same by piston opening and closing air inlet and exhaust outlet, make the fuel constant volume burning.

In addition, also the effect that can replace fan with combustion chamber is independently promptly introduced compressed air, input fuel and open exhaust outlet after completing combustion from compressor and sprays waste gas at a high speed and produce thrust, just can increase substantially power under the situation that does not change the turbogenerator core engine.Also go for transforming the afterburner of turbogenerator, new afterburner (piston mechanism that comprises barrel shape combustion chamber and switch air inlet, exhaust outlet) under the low-speed condition air inlet and thus exhaust outlet is all opened or adopt bypass passageways to make the low temperature low speed flow of being discharged by fan have free passage produces thrust; And in the next employing pulsed mode of high-speed flight state, close air inlet at certain hour after entering (new) afterburner from the low temperature low speed flow of fan by air inlet, input fuel and completing combustion under the constant volume condition, thereby the pressure of HTHP waste gas acts on piston and opens the waste gas that exhaust outlet discharges at a high speed after the fuel completing combustion by piston and produces thrust, and fan is equivalent to the low-pressure compressor of " parallel connection " and whole system is equivalent to a turbojet; So fuel combustion is more abundant, temperature and pressure is higher thereby possess higher efficient and bigger thrust, simultaneously do not need to transform engine basic structure, do not need to change the loop parameter such as the pressure ratio of engine self, turbine inlet temperature, air mass flow and bypass ratio or the like and the just simple afterburner of transforming just can realize that " becoming circulation " work, when subsonic speed cruises, reduce oil consumption and noise and when acceleration and high-speed flight, possess high thrust, make engine under various flights and duty, all possess outstanding performance, satisfy the needs of Concord and big flight envelope multitask fighter plane.The afterburner of common military fanjet only can produce 1.5 times afterburning thrust, such as military thrust is that 10 tons of then afterburning thrusts are 15 tons, yet adopt the constant volume pulse combustor then can produce 2.5-3.5 afterburning thrust doubly as afterburner, promptly military thrust is that 10 tons of afterburning thrusts are the 25-35 ton.

Advantage of the present invention:

1. the efficiency of cycle of constant volume burning is 47%, and the efficiency of cycle of constant pressure combustion is 27%.

Thermal efficiency height, specific fuel consumption is low, simple in structure, energy density is high.

3. make turbogenerator under slow-speed of revolution operating mode the thermal efficiency consistent during with high rotating speed.

4. higher ignition temperature and pressure bring higher energy and thrust.

5. the temperature and pressure increase then can reduce combustion chamber length and volume.

6. punching engine speed span is increased, in the scope of hypersonic speed (such as 2-15 Mach), all can guarantee the engine operate as normal, thereby simplify engine design from low supersonic speed.

Shortcoming of the present invention:

1. higher ignition temperature reduces the combustion chamber life-span.

2. the pulsed of piston moves back and forth and to cause combustion chamber and engine vibration, reduces structural life-time or influences the installation and the use of payload.

3. the pulse operation mode makes power density may be lower than common constant pressure combustion pattern under some application conditions, may can increase the volume and weight of engine on the contrary.

4. when being applied to turbojet and replacing fan with the combustion chamber, the low temperature low speed flow that the High Temperature And Velocity air-flow that is used to produce thrust is compared turbofan has the more energy loss, and then efficient is lower under lower flying speed.

Description of drawings:

As shown in Figure 1, this is the schematic diagram of gas delayed blowback inverse recoil system.Delayed blowback inverse recoil system is by cylinder, gas block and will (according to arrow indicated direction among the figure) be assemblied in the head of cylinder respectively and the piston mechanism of afterbody is formed; The sensing of gun barrel and cylinder among this figure (afterbody to the direction of head, air admission hole to the direction of steam vent or the cartridge chamber direction to the thorax mouth) is identical, and also can make the directed in opposite of gun barrel and cylinder according to the different design needs of weapon; Cylinder head has steam vent and afterbody has gas port, and gun barrel has gas port near the position of cartridge chamber, connects gun barrel and cylinder communicates the gas port of the two by gas block; After the ammunition percussion, partly (imperfect combustion) powder gases enters in the cylinder by the gas port on the gun barrel, passage in the gas block and the gas port on the cylinder and burns away; Under the powder pressure effect, the piston mechanism that is installed in tail cylinder the moment of setting with the gas port on the shifter cylinder, the piston mechanism that is installed in cylinder head will be opened steam vent on the cylinder constantly at another, and the powder gases after the completing combustion is sprayed at a high speed from steam vent; Utilize the momentum of this part powder gases and set its direction of motion as required, just can realize the recoil of delayed blowback principle with the balance gun barrel.

As shown in Figure 2, this is the structure chart of the piston mechanism of tail cylinder assembling.The piston bush of the fixing assembling of tail cylinder hollow round tubular, the dead in line of cylinder and piston cover, and hold piston jointly and move along axis direction therein; Piston is that the outside has circular projection (part between end face B and the end face C as shown in the figure) and the pipe of internal openings and end sealing, and opening direction is over against tail cylinder; The piston rear portion have passage so that the formed air chamber of end face C, piston bush and outer surface of piston these two is communicated with cylinder; Cylinder, piston bush, end face B are not communicated with cylinder with the air chamber that outer surface of piston forms, and can seal with the maintenance atmospheric pressure that yet can communicate with external environment as gas spring.

As shown in Figure 3, this is piston motion principle figure.After the ammunition percussion, the part powder gases enters cylinder by gas port, and the powder gases after the burning expansion can be considered as the homogeneous (uniform) fluid of each several part pressure unanimity; At axis direction, powder gases acts on piston end face A, end face C and piston base simultaneously; Area by design end face C, make it as required greater than the area sum of end face A and piston center hole, so (along axis direction) active force with joint efforts can be much smaller than powder gases for piston at the active force of either direction and can come to set arbitrarily the size of making a concerted effort as required, make piston produce speed that design needs and as the direction of arrow indication among the figure and to the motion of cylinder direction, just can make piston in the moment process gas port position of needs and it is closed.In addition, such structure obviously can make this piston that is in tail cylinder directly as piston in the gas operated automatic principle and piston rod, as long as make piston reverses direction motion (need make the area of piston end surface C less than needing to have gas port on end face A and piston center hole area sum and the piston by design) or utilize the motion of lever drives breech housing.Be noted that, reach among this figure and among each figure resetting of piston do not done description subsequently, just simple usually assembling back-moving spring or the direct air chamber (space that forms between piston end surface B, piston bush, outer surface of piston and the cylinder tail end) that is not communicated with powder gases that utilizes just can be realized resetting of piston as gas spring; Need explanation equally, each figure in the Figure of description is only for illustrating that principle of the present invention do not represent concrete physical dimension, ratio and speed.

As shown in Figure 4, when cylinder bore too small (when being applied to small-bore rifle) and when being not suitable for holding piston and moving therein, the piston and the piston bush that then need larger diameter, so mounting means is changed into cylinder and piston bush assembles with gas block is fixing respectively, does not then need to have gas port on the cylinder.

As shown in Figure 5, this is the structure chart that assembles in gun barrel in order to the piston mechanism of switch gas port.This assembling mode is fit to combine utilization with " the free barrel extension and recoil type automatic principle of thorax inner carrier ".Have passage and gas port on the piston, wherein the piston bush position of gas port correspondence also has gas port; Gas block connects piston bush and cylinder and the gas port of the two is communicated, after the ammunition percussion, the part powder gases enters the air chamber of end face C, piston bush and outer surface of piston formation respectively and enters in the cylinder by the gas port on piston and the piston bush (and through the gas port on gas block and the cylinder); At axis direction, powder gases acts on piston end face A, end face C and cartridge chamber bottom simultaneously, area by design end face C, make it as required less than the area sum of end face A and piston (end face A place) centre bore, make piston produce movement velocity and direction motion at the bottom of thorax that design needs, just can make piston on the moment process piston bush of setting the gas port position and it is closed.Figure as can be known thus, bullet places gun barrel (gas port need be opened at the bullet rear portion) if adopt submunition then can make shell case and propellant powder place cylinder, piston can be arranged in gun barrel or the cylinder flexibly, and such structure is fit to the situation that the ammunition axial dimension is bigger or launching condition is limited to.

As shown in Figure 6, this is the structure chart in order to the piston mechanism of switch pair pore of cylinder head assembling.The piston bush of the fixing assembling of cylinder head hollow round tubular, the two dead in line, and hold piston jointly and move along axis direction therein; Piston is that the outside has circular projection (part between end face B and the end face C as shown in the figure) and the pipe of internal openings and end sealing, and opening direction is over against cylinder; The piston rear portion have passage so that the formed air chamber of end face C, piston bush and outer surface of piston these two is communicated with cylinder; Cylinder, piston bush, end face B are not communicated with cylinder with the air chamber that outer surface of piston forms; Cylinder in steam vent place fitted with nozzles in order to quicken powder gases it sprayed at a high speed and to control its emission direction; Piston closes steam vent during original state, enter the expansion that burns away of powder gases in the cylinder, continue to act on piston end face A simultaneously, end face C and piston base, design the area of end face C as required, make it as required less than the area sum of end face A with (end face A place) piston center hole, so (along axis direction) active force with joint efforts can be much smaller than powder gases for piston at the active force of either direction and can come to set arbitrarily the size of making a concerted effort as required, make piston produce movement velocity that design needs and to the motion of piston base direction, just can be in the moment process steam vent position of setting so that jet pipe (passing through steam vent) is communicated with (promptly " opening " steam vent) with cylinder.(illustrate: the too small situation of cylinder bore is next can be) with reference to the represented method of Fig. 4

As shown in Figure 7, this is the gas backwash schematic diagram.After steam vent " was opened " by piston, the gas in cylinder direction as indicated in FIG. entered jet pipe (utilizing " convergent divergent nozzle " usually) gas of HTHP is sprayed at a high speed; The sensing that changes jet pipe can determine the emission direction of gas; Gas backwash forms the active force to jet pipe, and force transmission is delivered on the gun barrel to cylinder and by cylinder and gas block, forms the active force along the axial inverse recoil of gun barrel.(special application: it is vertical with the gun barrel axial line that jet pipe is pointed to, in order to the turning torque to weapon of balance gun barrel and the generation of automatic machine recoil-for example the be used for inverse recoil system of pistol or howitzer.)

As shown in Figure 8, this is only to assemble the structure chart of piston mechanism in order to the switch pair pore in gun barrel.This assembling mode is fit to combine utilization with " the free barrel extension and recoil type automatic principle of thorax inner carrier ".Have steam vent on the piston bush (broadly being the part of gun barrel) and be connected with jet pipe; After the ammunition percussion, the pressure of powder gases acts on piston, area by design end face C, make it as required less than the area sum of end face A and piston (end face A place) centre bore, make piston produce movement velocity and direction motion at the bottom of thorax that design needs, thereby the steam vent position that piston end face A was moved on the piston bush in the moment that bullet goes out thorax makes gun barrel communicate with jet pipe by piston bush and the steam vent on it, so the interior high pressure powder gases part of gun barrel from the thorax mouth spray forward and a part steam vent and jet pipe spray (direction as shown by arrows) backward thus.

As shown in Figure 9, this is a kind of combustion chamber and piston structure schematic diagram of constant volume burning pulsed motor.Starting stage, air inlet is opened and exhaust close; Compressed air (being fuel and oxidant in the application of rocket engine) enters from air inlet and is full of the combustion chamber, spray into fuel (in the application of rocket engine, just passing through igniting) burning afterwards, initial stage in burning is that internal pressure of combustion chamber begins the sharply initial stage of increase, the piston that combustion gas acts on air inlet moves its axis direction along the combustion chamber and closes air inlet, and perhaps (under the enough condition of pressure) just promotes piston by the pressure of the compressed air self of input and close air inlet; The pressure of combustion gas acts on the piston that is assemblied in the exhaust outlet position in the combustion process, make piston move and move to the position of exhaust outlet when fuel gas temperature and the pressure maximum (being completing combustion) thereby make it along axis direction and open, high-temperature high-pressure fuel gas quickens and discharges by jet pipe.

As shown in figure 10, this is a kind of combustion chamber and air inlet piston structure schematic diagram of integrated design.Combustor outer casing and piston bush are integrated and are round tube shape structure, columned deflection cone is installed on the piston bush by commutator segment, piston moves back and forth between deflection cone and piston bush and vertically, and the space between deflection cone and the piston bush is (circular) air inlet.This figure is the structure cutaway view of closing the air inlet state, promptly after compressed air such as arrow points enter the combustion chamber by air inlet, the exhaust gas pressure at air pressure or burning initial stage acts on piston end face C (utilizing the active force that also comprises under the situation of exhaust gas pressure end face A) makes piston to the motion of air inlet direction, and closes air inlet in the moment of setting behind the motion certain distance.

As shown in figure 11, this is a kind of combustion chamber and exhaust outlet piston structure schematic diagram of integrated design.Combustor outer casing and piston bush are integrated and are round tube shape structure, columned deflection cone is installed on the piston bush by commutator segment, piston moves back and forth between deflection cone and piston bush and vertically, and the space between deflection cone and the piston bush is (circular) exhaust outlet.This figure is the structure cutaway view of closing the exhaust outlet state, when promptly producing pressure, the combustion chamber fuel combustion acts on end face A and end face C, area by design end face C, make it as required greater than the area of end face A, make piston produce speed that design needs and to the motion of combustion chamber direction the direction of deflection cone (promptly away from); Begin to open exhaust outlet and this moment of fuel completing combustion just at the moment piston of setting behind the motion certain distance, (incorporate, circular) jet pipe of the convergence that forms between diversed awl of waste gas and piston bush diffusion quickens and discharges at a high speed as arrow points.Dock with combustion chamber and air inlet piston mechanism illustrated in Figure 10, just can constitute a complete constant volume burning pulsed motor combustion chamber subsystem.Common this structure is suitable under piston end face A and the relatively large situation of the ratio of internal diameter.

The specific embodiment:

Be applied to armament systems and adopt cylinder.

(illustrate: in this part, adopt simplification calculating and estimation so that show mentality of designing, method for designing and account form, be not in order to draw accurate design data more.)

For example, (as " desirable individual soldier fight weapon "-OICW and " OCSW "-OCSW) of the U.S., set the weapon design objective and be: bore 25mm, bullet quality 100g, initial velocity 500m/s, maximum bore pressure surpass the rifling part and the forcing cone part length overall 300mm of 200MPa, barrel to the 25mm High Velocity Grenade Launcher of researching and developing with reference to 25mm cannon and various countries; Require recoil momentum and common 7.62mm rifle suitable (being approximately 14Ns) can be no more than 400mm to shoulder and motor-driven emission, cylinder (not comprising piston mechanism) length to reach; Known conditions is: cylinder points to and powder gases opposite with barrel and recoils the momentum efficient of direction and parallel, the existing thorax mouth of barrel axis muzzle brake greater than 50%.

According to the structure of meaning illustrated in figures 1 and 2, cylinder (pointing to that indicated in the drawings opposite) and gas block are installed on barrel.According to thorax mouth kinetic energy, estimation propellant powder quality is approximately 13g, barrel recoil momentum is estimated as 59Ns.So, need the momentum of the recoil of the powder gases in the cylinder to be about 45Ns.Set that the gun pressure after the powder gases completing combustion is 100MPa in the cylinder, according to formula:

$V_e=\sqrt{\frac{\mathrm{TR}}{M}\·\frac{2k}{k-1}\·[1-{(P_e/P)}^{(k-1)/k}]}$

Wherein, V _e=nozzle exit exhaust velocity, m/s

The thermodynamic temperature of T=inlet gas, K

R= Universal gas constant=8314.5J/ (kmolK)

M=gas Molecular mass, kg/kmol (also claiming molecular weight)

K=c _p/ c _v= Adiabatic exponent

c _p=gas is under the constant voltage Specific heat

c _v=gas specific heat at constant volume

P _e=exit gas Absolute pressure Pa

P=inlet gas absolute pressure, Pa

(get k=1.22, M=25kg/kmol) can calculate that the powder gases deflation rate is about 2500m/s when P=100MPa and T=2400k (considering the thermal loss of powder gases in the cylinder), and speed is about 1720m/s during 1MPa (promptly approximately be exhaust end), the mean value that gas ejection speed in the journey is broken through in negate is about 2100m/s, therefore, (cylinder) powder gases quality that is used for recoiling is 21.5g, and then total propellant powder quality is 34.5g.According to formula:

$(p+a\frac{n^2}{V^2})(V-\mathrm{nb})=\mathrm{nRT}$

Calculate volume of cylinder (temporarily ignoring piston mechanism internal capacity part) and be about 191cm ²(to get the covolume coefficient be 0.9 and ignore the pressure correction item for convenience of calculation because of gunpowder kind decision a and this place of b), get cylinder bore diameter and be 25mm then cylinder length be about 390mm.

Propellant powder in the gun barrel is in combustion process, and the powder grain partial combustion becomes high temperature and high pressure gas and partly still is incompressible solid, is gas-solid two-phase mixture matter in the gun barrel; Solid propellant grain can be regarded as uniform fluid on the one hand and " flow " together with gas in gun barrel, solid particle evenly distributes in thorax and in the gas on the other hand, and it is promptly identical with solid particle speed with approximate reflection inner trajectory process along axis direction gas therefore can be considered as homogeneous flow; So the gunpowder emission process can be modeled as the stack of two combustion processes, promptly the 13g powder burning expand the acting result that other 21.5g powder burning expands when promoting the bullet emission can be taken as be used for " emission " self to cylinder; When the physical dimension of gun barrel and explosive payload (calculating with 13g) are determined, then its " gun pressure-time " (P-T) curve can calculate also and can survey out, setting from gun pressure is 0 beginning and will be at t=t ₁The time gun barrel in gun pressure close gas port fully when be (dropping to) 100MPa (can select rational t1 value and gun pressure value flexibly) according to " gun pressure-time graph " from the highest 200MPa, suppose that now its time point (curve values that depends on reality in the actual design) is t ₁=0.5ms; The pressure of (supposing 8.96g burning becoming gas in the gunpowder of burning of gunpowder constant speed thereby gross mass 21.5g) when piston is closed gas port in the cylinder is tried to achieve by the equation of gas state and is about P=47MPa; In the cylinder pressure increase then the pressure on gas port both sides change the change of the volume that causes flow velocity and powder gases, according to " pressure-time graph " of gun barrel and cylinder and get its pressure differential, be effective pressure of emission gas-solid mixture matter; The gas that every increase in the unit interval dt (among the 8.96g) powder burning of dm quality produces all will effectively be launched into cylinder by gas port under the pressure action, and effectively pressure also can make the powder grain (the unburned 12.54g in the 21.5g gunpowder) of unit mass be launched in the cylinder simultaneously; The take arms gas port cross section of pipe is the control volume border, because the hypothesis powder gases is that homogeneous phase thereby speed equate with powder grain, thereby the emission of the emission of powder gases and powder grain can be distinguished the area separate computations of needed gas port; For powder gases, ignore its covolume then the relation of its density and pressure roughly be:

$\mathrm{\ρ}=\frac{P}{998}(g/{\mathrm{cm}}^3);$

According to formula:

m＝ρ*S*v*t，

$v=a*t=\frac{P*S}{m}*t,$

Wherein m is that the quality of powder gases, the effective area that S is gas port (being not equal to the area of the reality of gas port with time correlation), v are that speed, the t of propellant gas is the time of propellant gas, then has:

$\∂m=\frac{P}{998}*S*\frac{P*S}{m}*t*\∂t$

M=8.96g, t=0.5ms, P (supposing that 0.25ms reaches maximum bore pressure) average, and the effective area that then can try to achieve the gas port of emission 8.96g powder gases needs is about:

S＝145mm ²；

The density p of powder grain=1.6 (g/cm ³); The effective area that then in like manner can try to achieve the gas port of emission 12.54g powder grain needs is about:

S＝64mm ²；

The two addition is the effective area of gas port: S=209mm ²

By following formula as can be known, the size of the effective area of gas port is directly proportional with the quality of the gunpowder of required emission (gas and particle), the temperature of powder burning, and more quality, higher temperature need bigger area; Be inversely proportional to gun pressure, inner trajectory time, promptly higher gun pressure, longer inner trajectory time need littler effective area.

In concrete design process, need experimental data that the estimated value in this process (as the current difference of the temperature of powder gases, pressure, gas-solid mixture matter, covolume coefficient to the influence of the frictional force between the influence of the length of result's influence, energy loss, gas block internal channel and time, piston and the cylinder that gas port is closed in setting etc.) is revised, and need experiment to determine possible pressure oscillation, could calculate the effective area of gas port accurately.

Need the motion of piston close gas port then usually the real area of gas port should be 2 times of effective area or determine according to the movement velocity and the distance of piston.The area of supposing gas port in this example is 418mm ²Promptly set the piston setting in motion and promptly begin to close gas port, gas port for being 10mm, thereby the piston stroke of closing gas port is that 10mm and run duration are that 0.5ms (this equally need by the experimental data correction when design), the speed when piston is closed gas port fully are 40m/s along the rectangular opening of gun barrel circumference is axially long; Because the quality of piston (because cylinder bore diameter and maximum pressure one rule) can be set flexibly to a certain extent and increase and decrease and suppose that then piston mass is 120g, when piston is closed gas port in the cylinder pressure of (after the 8.96g completing combustion in the 21.5g gunpowder) be pressure linear change in P=47MPa and the hypothetical cylinder, be 491mm according to the area sum of end face A shown in Figure 3 and centre bore ², the area of therefore trying to achieve end face C is 900mm ², so the external diameter of piston outer circle annular projection is about 42mm.(in concrete the application if allow on the structure then can to set the piston direction of motion opposite and on piston the position of the gas port of corresponding cylinder also have the gas port of same size, the stroke and the run duration of piston are constant greater than the area of end face C promptly to set the area sum of piston end face A and centre bore, and then the area of end face C will be 83mm ², therefore the external diameter of circular projection is about 27mm.)

The stroke of opening steam vent is relevant with the area of steam vent, its area is determined (when being commonly used to balance barrel recoil the area of steam vent identical with the cylinder cross-sectional area be used for during turning torque that the balance recoil produces then less relatively in the hope of long action time) according to the time of cylinder bore, exhaust velocity, exhaust process needs, the speed that can determine its axial dimension thus and open piston before the steam vent.The speed of supposing must to ask as calculated piston when opening steam vent is that 25m/s, piston are that 1.2ms, piston mass are assumed to be equally that pressure is 100MPa in 120g, the cylinder from setting in motion to the time of opening steam vent when opening steam vent (piston speed reaches 25m/s), is 491mm according to the area sum of end face A shown in Figure 6 and centre bore ², the area of therefore trying to achieve end face C is 441mm ², piston the external diameter of circular projection be about 34.4mm; And if adopt integral structure shown in Figure 11, the thickness of pipe of supposing piston be 5mm then the area of end face A be 314mm ², so the area of end face C is 364mm ², piston the external diameter of circular projection be about 33mm.

Be applied to armament systems and only in gun barrel, assemble the piston mechanism that is used for exhaust.

The piston that only needs the switch pair pore because do not need to be designed for the piston of switch gas port is therefore as long as adopt and computational methods design piston end face area like the application class that is equipped with cylinder.Difference is, because the temperature in the thorax when powder gases quality and exhaust, pressure are usually all less than the situation of the design of using cylinder, therefore the momentum of recoil is less than the situation of using cylinder usually, and is promptly only less demanding thereby can to make designs simplification be to use under the situation of cancellation cylinder in inverse recoil efficient usually.

For example, be the weapon and the performance indications thereof of the 25mm grenade launcher in the precedent equally, suppose that the propellant powder quality is that the Mean Speed of 13g, powder gases (from thorax mouth and steam vent) ejection is estimated as 1500m/s, powder gases and respectively has 50% to be 50% from (momentum) efficient of thorax mouth and steam vent ejection, thorax mouth muzzle brake respectively, then total recoil momentum of grenade launcher is 45Ns, and the total recoil momentum before adopting gas delayed blowback inverse recoil system is 59Ns.It is 24% that then total (momentum) system is moved back efficient.

Suppose according to piston structure shown in Figure 8 (being that cartridge chamber is at internal piston), average effective pressure to be that 85MPa, piston mass are that the area of 500g, end face A is 471mm ²(being that piston external diameter is 35mm), speed is 8m/s (move distance is 4.8mm) when requiring piston to open steam vent, the area that then can calculate end face C is 923mm ², piston the external diameter of circular projection be about 49mm; Adopt piston structure shown in Figure 10 (its internal diameter of the piston of through type is 25mm) if make piston not comprise cartridge chamber part and in gun barrel is assemblied in piston bush to alleviate piston mass, suppose that its quality is that the area that 150g then can calculate end face C is 11.8mm ², circular projection diameter be about 35.2mm.

The constant volume burning pulsed motor.

Be applied to the combustion chamber of gas-turbine unit, punching engine and rocket engine, its structure is with to be applied to the cylinder and the piston mechanism of armament systems similar, all be by the barrel formula combustion chamber that can bear HTHP, be assemblied in piston mechanism on the barrel, the spout portion that is communicated with barrel by the exhaust outlet that is opened and closed by piston is grouped into; The piston mechanism that air inlet and being used to opens and closes air inlet again with cylinder on gas port and to open and close the piston mechanism of gas port similar, therefore can adopt design and the computational methods identical, under the numerical value of pressure, ignition temperature and the pressure of given gas that is conveyed into the combustion chamber or fuel mixture, pulse frequency, calculate the physical dimension of quality, face area and the barrel of piston with the armament systems that assemble cylinder; Wherein, by air inlet input be that fuel-oxidant mixture then can only utilize the pressure of mixture self to act on piston to close air inlet usually, and can utilize when just compressed air by the air admission hole input or oxidant the pressure of itself and the pressure at burning initial stage to act on piston and close air inlet.

For example, certain fanjet constant volume pulse afterburner is that the tubular combustion chamber of 50MPa combines by several internal diameters 36mm, maximum pressure, the external diameter 36mm of air inlet and exhaust pition and internal diameter is 25mm; Air inlet speed is that 600m/s and deflation rate require to be 1800m/s, then can calculate EGT under the standard atmosphere condition and be about 1800K; Supposing to set the exhaust pition quality according to the piston structure of Figure 11 the speed that is 150g, requires piston to move to unlatching exhaust outlet position is that 10m/s, input fuel and needed time of completing combustion are 5ms, and the area that then can calculate piston end face C is 539mm ², piston the external diameter of circular projection be about 44.5mm; If the air inlet piston need be set at close when pressure reaches 5MPa in the combustion chamber and suppose pressure be linear change and ignore admission pressure, speed is 25m/s when supposing to require piston to close air inlet fully, to set the air inlet piston mass according to piston structure shown in Figure 10 be 150g, the area that then can calculate air inlet piston end face C is 3000mm ², piston the external diameter of circular projection be about 71.5mm.Suppose that air inlet and evacuation time are 5ms, then the pulse frequency of combustion chamber working cycles is 66Hz to the maximum, therefore needs three constant volume pulse combustors to be one group and takes turns to operate to realize the circulation of steady and continuous air inlet, burning, exhaust.

Need to prove, such account form reckons without the into energy of answering of piston, this can come from the interlock of exhaust pition and air inlet piston thereby need the quality of joint account piston, increase energy storage equipment and change (air inlet and exhaust) thus the area of piston end face C is advanced again by the piston that the chemical energy in the combustion chamber provides energy that piston advances again or the high-temperature high-pressure fuel gas in combustion chamber of drainage to drive another combustion chamber automatically; On the other hand, the aforementioned calculation process is just in order to describe the motion principle of piston, and say from angle of practical application, in order to realize safer air inlet efficiently and exhaust cycle, usually need by each exhaust pition of one group of combustion chamber in turn (the perhaps combustion gas effect under the exhaust pition control) drive the air inlet piston, this also makes the size of air inlet piston and piston bush and weight reduce, and compact conformation is reasonable.

Claims (3)

1. One of technical characterictic of the present invention be to utilize piston mechanism as switch application in various weapons with pipes system, thereby powder gases can need be after the emission bullet be sprayed at a high speed to the opposite direction of bullet motion according to design forms the recoil that therefore active force of barrel is reduced even offsets barrel, thus the design of the unique texture of piston follow the principle of pressure unequal-area guaranteed only to rely on gunpowder energy can according to design need the realization automatic switch function and do not need extra power.
2. 2. two of technical characterictic of the present invention be to utilize piston mechanism as switch application in gas-turbine unit, punching engine and rocket engine, thereby the unique texture of piston design is followed the principle of pressure unequal-area and has been guaranteed only to utilize the energy of fuel or working medium self and do not need extra power thereby to make the fuel constant volume burning according to the function of design needs realization automatic switch.
3. Utilization the present invention described in the claim 1 or 2 exclusive technology and this technology is embodied as product, its technical characterictic be according to the principle described in claim 1 or 2 and uses the exclusive technology of the present invention described in the claim 1 or 2 could constitute a complete product as the part of necessity.

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