Compensating muzzle brake (CMB) with supersonic gas stream interruption system

Abstract

FIELD: gas units. SUBSTANCE: muzzle brake-compensator (MBC) with a system for interrupting a supersonic gas flow contains a housing, annular elements connected to each other by cutting off chambers with nozzles. The nozzles are united by an internal through channel for the passage of the projectile and the gas jet. In the working area of each cut-off chamber, at least one side outlet window is located so that when the MBC is installed on the end of the weapon barrel, the side outlet windows of each chamber are oriented perpendicularly or at an angle back to the direction of the outgoing gases. EFFECT: technical result is an increase in the effectiveness of the muzzle device, a decrease in recoil and a decrease in toss when fired.

Claims

1. A compensating muzzle brake for use with a firearm having a barrel having an internal barrel channel for passing a projectile and a gas stream in a direction of fire, the barrel channel defining a central barrel axis, and the barrel channel having a cross-sectional area, s.sub.2, wherein the compensating muzzle brake comprises: a tubular body installed or for installation on the barrel, wherein the tubular body defines: an internal through channel for passing the projectile and the gas stream, wherein the through channel is aligned and continuous with the barrel channel when the tubular body is installed on the barrel; and at least one internal cut-off chamber, wherein each one of the at least one cut-off chamber comprises a nozzle and at least one side port, and is terminated by a circular element such that, with the tubular body installed on the barrel: the nozzle defines an inlet for passing the projectile and the gas stream from the internal through channel into the cut-off chamber; wherein an inner diameter of the nozzle gradually increases along the nozzle in the direction of fire from the inlet toward the circular element; wherein a caliber of the nozzle is defined by the inner diameter the nozzle at the inlet; the at least one side through outlet port is located in a side of the nozzle and oriented perpendicularly or at a non-perpendicular angle back toward the central barrel axis; wherein a total sectional area, s.sub.1, of the at least one side through outlet port for each one of the at least one cut-off chamber is at least twice the cross-sectional area, s.sub.2, of the barrel channel; the circular element comprises a flat annular surface having an outer diameter of at least 2 times the caliber and having a central hole for passing the projectile and the gas stream from the cut-off chamber to the internal through channel; wherein the flat annular surface faces opposite to the direction of fire and is located opposite to the inlet of the nozzle; wherein a distance, h.sub.1, in the direction of fire, from the flat annular surface to the inlet of the nozzle is equal to at least the caliber; wherein the at least one side through outlet port is located, in the direction of fire, between the inlet of the nozzle and the flat annular surface; and the circular element further comprises a concavely curved surface that interfaces a periphery of the flat annular surface with a peripheral end of the nozzle and provides for deflection of gas sidewards and opposite to the direction of fire and through the at least one side through outlet port.

2. The compensating muzzle brake of claim 1, wherein the at least one cut-off chamber comprises a plurality of cut-off chambers that are arranged sequentially and spaced apart, in the direction of fire, along the tubular body and interconnected by the internal through channel of the tubular body.

3. The compensating muzzle brake of claim 2, wherein the cut-off chambers are separable from each other.

4. The compensating muzzle brake of claim 2, wherein the distance, h.sub.1, for a first one of the plurality of the cut-off chambers differs from the distance, h.sub.1, for a second one of the plurality of the cut-off chambers.

5. The compensating muzzle brake of claim 2, wherein the plurality of the cut-off chambers comprises five or less cut-off chambers.

6. The compensation muzzle brake of claim 5, wherein the plurality of the cut-off chamber comprises three cut-off chambers.

7. The compensating muzzle brake of claim 1, wherein an inner surface of the nozzle has a truncated conical shape.

8. The compensating muzzle brake of claim 1, wherein the concavely curved surface comprises a toroidal surface.

9. The compensating muzzle brake of claim 1, wherein the at least one side through outlet port is oriented perpendicularly to the central barrel axis.

10. The compensating muzzle brake of claim 1, wherein the at least one side through outlet port is oriented at a non-perpendicular angle back toward the central barrel axis.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The following drawings illustrate the proposed construction less all the CMB versions.

(2) FIG. 1A is a general view of a compensating muzzle brake.

(3) FIG. 1B is a general and side view of a compensating muzzle brake.

(4) FIG. 1C is a general view of a compensating muzzle brake, along longitudinal section A-A of FIG. 1B.

(5) FIG. 1D is a general and cross-section view of a compensating muzzle brake, along cross-section B-B of FIG. 1A.

(6) FIG. 2 is an isometric sectional view of the CMB.

(7) FIG. 3 is a digital visualization of velocity of gas streams.

(8) FIG. 4 is a gas stream monogram with digital visualization of normal shock waves when confronted with the flat circular elements.

DESCRIPTION OF PROPOSED EMBODIMENTS OF THE INVENTION

(9) The CMB is designed as follows. The tubular nozzle has a body (1) that is placed on barrel end (2). Attached to the muzzle end of the barrel (3) or through the intermediate chamber is a first cut-off chamber (4) that comprises a nozzle (5) having a critical cross-section (6) that is the narrowest part, and then the nozzle is interfaced with the circular element (7), a part of which is a flat annular surface (8). A circular element (7) has a shape of a plate in the cross-section and includes a concavely curved surface, for example, having a surface in the form of a circular groove (e.g., a toroidal surface) that is interfaced with a surface of side through outlet ports (9) on the periphery and has a bottom in the form of a flat annular surface (8) in the center with an outer diameter of not less than 2 calibers and having a hole (10) in the center for passing a projectile without obstruction. The first cut-out chamber (4) is interfaced with the second cut-off chamber (11) that includes the same elements. One through five cut-out chambers may be used. A length of each chamber h.sub.1 is digitally simulated using the model that meets the conditions for a circular active zone “a” in which is provided formation of a normal shock wave in an incoming supersonic gas stream produced between a flat circular element (8) and critical cross-section (6) of the nozzle (5). For formation of a normal shock wave, the requirement is that the supersonic gas stream flowing out of the nozzle (5), while climbing on the flat annular surface (8), in each cut-out chamber (4) gas-dynamic and thermodynamic conditions are produced, so that they are to be essential and significant for reliable formation of a stable normal shock wave produced in the space between the critical cross-section (6) of the nozzle (5) of this chamber (4) and the flat annular surface (8) acting as a reflecting (deflecting) obstacle. Since parameters of the outflow stream vary as long as it runs through the CMB, a length of each cut-out chamber (4) is simulated individually using a digital model. An example of gas outflow is shown in the digital model (FIG. 3). A normal shock wave is occurred at the distance h.sub.2 from the obstacle a stream climbs on, particularly, from the flat annular surface (8) the distance to which h.sub.1 from the critical cross-section (6) of the nozzle (5) of the chamber (4) depends on pressure difference inside the cut-off chamber (4), as well as on density, viscosity and temperature of the outflow gas and diameter of the critical cross-section (6). Such distance h.sub.1 is calculated individually for each cut-off chamber. A flat annular surface (8) is provided with an outer diameter of not less than 2 calibers. Circular active zones “a” are employed inside the circular element (7), wherein a high-pressure domain “b” is formed at the expense of the normal shock wave caused by interaction with the flat annular surface (8) of the gas stream flowing via the nozzle (5) out of the central channel “c” inside the active zone “a” of each cut-off chamber (4). The side through outlet port (9) is provided in such a way that, with the CMB installed on the barrel end (2) of the firearm, the side through outlet ports (9) of each chamber (4) are oriented perpendicularly or angularly back to the barrel axis and have the total sectional area “s.sub.1” for each chamber that is at least twice the area “s.sub.2” of the cross section of the central channel (“c”) of the barrel (2). A circular element (7) is a gas-reflecting (deflecting) plate-shape disk with a hole (10) in the middle provided in its central part with a flat annular surface (8) interfaced with a peripheral end of the cut-off chamber (4) by a smooth passage providing for smooth turn-back and reflection (i.e., deflection) of gas sidewards and backwards with reference to the direction of fire to the side through outlet port (9). The abovementioned configuration of the cut-off chamber (4) provides conditions wherein the distances in the cut-off chamber (4) between the flat annular surface (8) and critical cross-section (6) of the nozzle (5) are sufficient for forming a stable normal shock wave.

(10) Accordingly, the terminology accepted in this description meet the following meanings. A cut-off chamber is a nozzle, terminated by a circular element (plate) wherein a flat annular surface (a washer of annular shape) is applied, and the nozzle has a side through outlet port.

(11) A critical cross-section of the nozzle is the least cross-section of the nozzle wherein it corresponds to the cross-section of an inlet of the nozzle.

(12) The CMB functions as follows.

(13) On the path of a gas stream, at a calculated distance sufficient for formation of the normal shock wave, a so-called Mach disk, being equal to not less than one caliber (i.e., inner diameter) of the critical cross-section (6) of the nozzle (4), is placed a plate-shaped reflector (deflector) (i.e., a circular element (7)) based on the flat disk (i.e., flat annular surface (8)) which diameter is not less than two calibers. The peripheral outlet end of the cut-off chamber (4), by means of a smooth passage, provides for smooth turn-back and reflection (deflection) of gas sidewards and backwards with reference to the direction of fire from the side through outlet ports (9) that are located on the side of the nozzle (5).

(14) In this case, a gas stream interacting with the flat annular surface (8) will be exposed to a normal shock wave “b” and, as a result, will produce in the cut-off chamber (4), for gas streams flowing out of the side through outlet ports (9), pressure to be twice as much as pressure in the classical CMB of the known construction. This is illustrated in FIG. 3 showing distribution of gas streams in the proposed construction.

(15) High pressure in the chamber will cause, in its turn, creation of a significantly exceeded compensating reactive force. A normal shock wave is described, for example, in the publication [Mkhitaryan A. M. Aerodynamics, —M: “Mechanical Engineering”, 1976].

(16) By the normal shock effect is explained that while decelerating a supersonic gas stream, when gas particles transfer from the lower pressure domain to that of higher pressure, an abrupt (breaking) variation of parameters is produced—i.e. formation of a surface of discontinuity called a shock wave. Surfaces of discontinuity may be plain or curved differently oriented towards a velocity vector. If a surface of discontinuity is normal to the stream velocity, a shock wave is called normal. A shock wave (or a blast wave) is followed by abrupt decrease of speed and increase of pressure and temperature with kinetic energy being run out. Shock waves are produced not only when gas is freely flowing out of the jet nozzle to atmosphere but, for example, when supersonic current takes place inside the channel. Distances h.sub.1 are calculated on the base as follows: If an obstacle on which a supersonic stream climbs on is a thin-walled pipe having thickness of walls less than a half of an inside diameter of the pipe, on the ends of the pipe will be formed oblique shock waves with a stream “resting” on them being forced to pass by an obstacle, i.e. only that stream will pass by the pipe from its outside that has time to expand to the outside diameter of the pipe or more by the time of climb. As for a central portion of the stream (that carries a major part of gas mass according to the Gauss distribution law), it continues running in the main pipe channel; The useful reactive force in the CMB is formed through the effect that causes a gas portion following a projectile turning back and kicking back in the direction opposite to an action of fire. The more portion of gas being kicked backed at higher velocity, the more compensating force is produced. A normal shock wave, if produced on a path of a gas stream acting as a higher pressure zone, will be, in a way, a dynamic obstacle to a stream running axially and, in its turn, will cause increasing gas rate flowing sidewards. If a supersonic gas stream climbs on a thick-wall pipe having thickness of walls equal or more than a half of an inside diameter of this pipe, as a result of interaction with gas trying to pass an obstacle in the form of pipe end walls, forward of the entire end surface of the pipe will be produced a normal shock wave. Therefore, an outer diameter of the flat annular surface (8) is selected as equal to not less than two calibers. Parameters and number of reflecting chambers may be either calculated initially or selected sequentially on the basis of gas outflow numerical simulation results throughout the finite element method: for example, with gas outflow parameters simulated at the exit section of the barrel, if based on the numerical simulation results, an optimal geometry of the first chamber (angle of opening and length of the nozzle; a distance to the flat annular surface that provides for formation of a normal shock wave in front) is selected; then, on the basis of knowledge of obtained parameters of gas flowing out of the channel after the first chamber, the second chamber geometry is selected and so forth until a gas stream running axially out of the next chamber starts flowing out at the rate not less than velocity of sound (thereby making impossible for a gas stream to run up with a bullet flying at supersonic velocity and avoiding any harmful perturbation effect it can be exposed to), or until the total length of sequentially assembled cut-off chambers (4) achieves the maximum permissible length restricted by specific design requirements.

(17) Formation of a normal shock wave inside the cut-off chamber forward of the flat annular surface is resulted from Navier-Stokes equations used for defining gas stream particle motion laws according to which the more pressure inside a stream to exceed pressure outside, the more angle of stream opening. For example, a vacuum-running stream will not flow out like a jet but a cloud, and if a stream flows into medium pressurized similarly likewise the stream, it does not actually expand and its flow-out pattern will look like a cord. In the case under study, a stream flows out into the terrestrial atmosphere in normal pressure and temperature conditions and, therefore, if to refer, for example, to pressure difference inside and outside a stream including its density, viscosity and gas temperature, a distance towards “the first barrel”—a location wherein a stream expands enough to produce a normal shock wave visualized as a Mach disk—can be calculated exactly enough. For normal atmospheric conditions and typical hot gases, a distance from the nozzle section to the normal shock wave will normally be not less than the nozzle diameter, but if gas in the vessel (cut-off chamber), a stream flows to, fails to run out in proper time, it will be compensated by increased pressure with the angle of opening reduced, thereby entailing increase of a length of distance to “the first barrel”—i.e. a Mach disk distance—a normal shock wave. The digitally simulated model of the proposed device is based on this principle. With these conditions satisfied, it is possible to gain maximum reactive deceleration performance by using a muzzle attachment in order to decrease recoil and rise effects after firing.

(18) Any side effect on using a plate-shaped reflecting system will be caused by radical decrease of forward-running gas flow rate, for example, when using 4 or more cut-off chambers (4) wherein supersonic flow of gas following a bullet is actually deteriorated at the last chamber outlet, thereby resulting in decrease of bullet perturbation effect and improvement of grouping.

(19) At the nozzle exit section but forward of the set-off chambers, in particular case, an additional intermediate chamber without any original outlet ports may be placed. Its function is to be a receiver (pre-collector) of powder combustion outflow gases either for improving a steady outflow pattern or for burning powder combustion gases up (for example, to reduce flashing effect). Also, a lateral surface of this chamber is adapted, where required, for boring through holes in the right required direction, so that additional gas streams creating additional reactive forces can be formed as those intended for compensating individual features of arms, ammunition or shooters.

(20) According to the shooting results obtained at the open-air field when testing a 223 caliber sporting rifle fitted with the described CMB unit by the elite sports shooter who used just low-grade standard cartridges for firing twice per a series, a 300 m spread did not exceed 12 cm, what was impossible using any other CMB units in the world market.