RU2792791C1 - Method for automated determination of correction for wear of artillery barrel channel during ballistic fire preparation - Google Patents

Abstract

FIELD: methods of ballistic preparation of firing of artillery pieces.

SUBSTANCE: method for automated determination of the correction for wear of the bore of an artillery gun in the initial velocity of the projectile during ballistic preparation of firing is as follows. A screen is installed on the muzzle, reflecting probing acoustic signals. Two sound ducts are installed in the gun bolt wedge, one of which is inserted into the charging chamber and the gun barrel, to probe an acoustic signal, the frequency of which changes, for example, according to a sawtooth principle. The second sound duct is used to output the acoustic signal reflected from the walls of the charging chamber and the gun barrel, to determine the maximum resonant frequency of the charging chamber and the gun barrel, at which the signal is clearly distinguishable at the noise level. Based on to the maximum resonant frequency, the total volume of the charging chamber and the gun barrel is calculated taking into account the speed of sound in the air; the total area of the holes and the length of the transmitting and receiving acoustic waveguides, as well as the harmonic number of the maximum resonant frequency of the acoustic signal. Then the projectile is sent into the channel of the rifled barrel and the bolt wedge is closed and its volume is calculated from the maximum resonant frequency of the charging chamber.

EFFECT: provision of an automated determination of the correction for wear of the bore of an artillery gun, as well as the simplification of measurements in the field.

3 cl, 5 dwg

Description

Technical field

SUBSTANCE: invention relates to methods of ballistic preparation of firing of artillery pieces.

The ballistic preparation of the gun includes the determination of corrections for firing due to [1]:

- wear of the bore of the gun;

- deviations from the normal (+15°C) temperature of the propellant charge;

- changes in the properties of a batch of propellant charges;

- ballistic characteristics of projectiles.

State of the art

The invention involves a method for determining the correction for shooting due to wear of the bore of the gun. When firing from artillery guns with a rifled bore, wear is characterized by elongation of the charging chamber, which leads to an increase in its volume and a decrease in the muzzle velocity of the projectile [1]. For regular artillery pieces, when the maximum allowable wear is reached, the decrease in the initial velocity of the projectile reaches 6%, which corresponds to a range error of up to 1 km [2].

At present, the wear of the barrel bore of rifled guns is determined by manually lengthening the charging chamber using the PZK device [1, 2]. According to the measured elongation of the charging chamber, using firing tables or computing devices, a correction for firing is determined. The time for deploying the slam-shut device, preparing it for operation, and determining the parameter for a six-gun battery reaches 30 minutes. The determination of the initial velocity of the projectile due to bore wear can be determined by the results of firing using an artillery ballistic station, the time for determining the parameter for the battery reaches 15 minutes. In addition, in order to increase the firing efficiency of artillery pieces with different wear in the division, the batteries are re-equipped with guns with similar bore wear [1].

The disadvantages of these methods are obvious. They are not operational, time-consuming, require additional measures. And the use of an artillery ballistic station is not applicable for sudden short fire raids, a gun rate of more than 5 rounds a minute and when firing precision-guided ammunition.

An analogue of this technical solution is a method for non-shooting determination and accounting for individual corrections for changing the initial velocity of the projectile for the gun (patent RU 2206042 for the invention application: 2001114587/02 IPC ⁷ F41G 3/12 published: 10.06.2003.

This analog proposes a method for a non-shooting method for determining corrections for changes in the initial velocity of a projectile when preparing a gun for firing. This ensures that the established correction for the change in the initial velocity of the projectile is entered into the ballistic computer, the fire control system, determined by the wear of the channel of a particular barrel and a particular batch of shots intended for use in the combat operation of the object for subsequent accounting for it when aiming the gun. This is achieved by the fact that the method of non-shooting determination and taking into account individual corrections for the gun to the muzzle velocity of the projectile includes:

- measuring the change in the diameter of the bore in the chamber part and the caliber part in given sections along the length of the bore and determining the profile of the section with high accuracy;

- determination of the depth of the chambering of the projectile into the worn barrel of the used gun (measurement or calculation) and the calculation of the depth of chambering of the adjusted volume of the chamber in the shell space;

- calculation of ballistic solution matching coefficients according to the initial velocity and maximum ballistic pressure specified in the form of the batch of shots, calculation of the initial velocity of the projectile of the used batch from the used barrel, taking into account the adjusted volume of the chamber and the wear of the barrel bore, calculating the individual correction for the change in the initial velocity, which simultaneously takes into account corrections due to batch properties and due to bore wear. Calculations are carried out using a computer program according to the approved method for calculating internal ballistics, which has received experimental confirmation;

- entering a certain individual correction into the channel for changing the initial velocity of the projectile into the ballistic computer of the object's fire control system, or taking it into account when preparing the initial firing settings for guns that do not have a fire control system, or a method for introducing corrections into fire control systems.

The disadvantages of this method include high labor intensity and time-consuming measurements, as well as changes in the diameter of the bore in the chamber and caliber parts in given sections along the length of the bore and determination of the section profile. Another analogue of this technical solution is a method for measuring the wear of the bore and a device for its implementation (patent RU 2368885 for the invention application: 2007125489/28 IPC G01N 3/56, G01B 13/12, F41A 31/02 (2006.01) published: 27.09.2009 Bulletin No. 27.

Since the wear of the barrel bore leads to a drop in the initial velocity of the projectile due to the breakthrough of powder gases, it is proposed to use the principles of hydroaeromechanics to measure wear. The principles of aeromechanics are widely used in mechanical engineering to diagnose the wear of parts of the piston group of internal combustion engines, according to the degree of air compression (peak pressure gauges or compression meters).

In hydrodynamics and gas dynamics, a substance flowing through a pipe is usually called a liquid, regardless of whether it is in a state of aggregation, liquid or gaseous.

In classical hydrodynamics, the problem of the pressure drop of a liquid in a pipe with a circular cross section is considered due to overcoming the flow resistance. There are two types of resistance:

- resistances that manifest themselves along the entire length of the flow, due to the forces of friction of fluid particles against each other and against the walls that restrict the flow;

- local resistance due to various kinds of obstacles installed in the flow, leading to changes in the magnitude or direction of the fluid flow velocity.

If a cylinder with known dimensions is placed in the investigated wellbore, then the problem of measuring the internal diameter of the wellbore is reduced to measuring the fluid flow through the annular gap.

The simplest and at the same time accurate methods for measuring fluid flow are volumetric and gravimetric.

With the volumetric method of measurement, the liquid flowing in the investigated shaft enters a specially calibrated measuring vessel, the filling time of which is accurately recorded by a stopwatch.

In the weight method, by weighing, the weight of the liquid entering the measuring tank for some fixed time T is found, its mass, mass flow rate are determined, and, knowing the density of the liquid, the volume flow rate is calculated.

An analytical solution to the problem of axial fluid flow under the action of a pressure drop in the annular gap formed by two coaxially arranged cylindrical surfaces is known (see, for example, Zhokhovskiy MK Theory and calculation of devices with an unsealed piston, M.: 1966).

For frictional laminar fluid flow, the flow rate in the gap between the cylinder (the inner surface of the bore) and the fixed piston (measuring cylinder), if the gap b is small compared to the diameter D, and if the piston is located in the cylinder not coaxially, but with maximum eccentricity (touch) , is determined by the expression:

where Q - fluid flow;

D is the diameter of the measuring cylinder;

b _o - bore wear;

P - pressure in the breech breech;

μ is the kinematic viscosity of the liquid;

l is the length of the measuring cylinder placed in the barrel.

Using the principles of hydroaeromechanics allows you to move from measuring the linear size of wear at the point of contact of the measuring pin to measuring the fluid flow in the annular gap, which is a function of bore wear.

A method for measuring bore wear and a device for its implementation (versions) a method for measuring bore wear (Fig. 1), includes installing a measuring cylinder 2 with known geometric dimensions in the desired section of the bore 1, creating excess pressure of the measuring fluid in the breech breech or gas and measuring the flow rate of the measuring liquid or gas flowing through the annular gap from the muzzle of the barrel. The implementation of the method is possible in the form of aerodynamic or hydrodynamic measurements.

On (Fig. 1) shows a device for measuring wear of the bore on the basis of aerodynamic measurements, which contains a measuring cylinder 2 placed inside the barrel 1 with known geometric dimensions, a compressor or compressed air cylinder 6, a main valve 8, a pressure regulator 9 and a manometer for measuring it 10, a flange for supplying compressed air to the breech 4, plugs for ejector holes 12, an outlet flange 5 with a lock 11 of the mounting rod 3 installed in the muzzle, a free discharge line 7 and a rotameter for measuring air flow 13.

To measure wear by the aerodynamic method, the following is carried out:

- bringing the trunk to a horizontal position;

- connection of the measuring cylinder with the adjusting rod;

- introduction into the desired section of the barrel of the measuring cylinder;

- installation of a muzzle flange with holes for the mounting rod and air outlet;

- installation of a sealing flange for supplying compressed air to the breech breech;

- installation of plugs on the ejector holes;

- connection of the air line to the sealing flange;

- installation with the help of a reducer and a pressure gauge of the required value of excess pressure in the breech breech;

- determination of the position of the rotameter float;

- determination of wear of the barrel bore according to the calibration schedule.

Compressed air supplied to the sealed breech, passing through the annular gap between the inner surface of the barrel and the outer surface of the measuring cylinder, is throttled to atmospheric pressure in the free discharge line. Air flow measured with a rotameter is a function of bore wear.

A device for measuring the wear of the bore (Fig. 2) based on hydrodynamic measurements, which contains a measuring cylinder 2 placed inside the barrel 1 with known geometric dimensions, an oil reservoir 14, a main valve 8, an oil pump 15, a pressure regulator 9 and a pressure gauge for its measurement 10, a flange for supplying oil to the breech 4, plugs for ejector holes 12, an outlet muzzle flange 5 with a lock 11 of an installation rod 3 installed in the muzzle, a free discharge line 7, a measuring vessel 16 and a stopwatch for measuring time its filling 17. The muzzle flange 5 contains a mounting rod lock and a reference index for determining the position of the measuring cylinder 2. By moving the measuring cylinder, it is possible to measure wear in any section of the barrel. The reading of the position of the measuring cylinder is carried out according to the scale applied to the adjusting rod. To achieve high measurement accuracy, it is possible to change the value of excess oil pressure in the breech breech within a wide range. The upper pressure limit is determined by the condition of laminar fluid flow in the annular gap. The type of pressure gauge is selected in accordance with the specified measurement accuracy (the error of the most accurate reference pressure gauges is 0.002-0.005%).

To measure wear by the hydrodynamic method, the following is carried out:

- bringing the trunk to a horizontal position;

- connection of the measuring cylinder with the adjusting rod;

- introduction into the desired section of the barrel of the measuring cylinder;

- installation of a muzzle flange with holes for the mounting rod and oil outlet;

- installation of a sealing flange for supplying oil to the breech breech;

- installation of plugs on the ejector holes;

- connection of the oil pump to the sealing flange;

- installation with the help of a reducer and a pressure gauge of the required value of excess pressure in the breech breech;

- Achieving a steady state of oil flow;

- collection of oil flowing from the muzzle of the barrel into a special dipstick;

- measurement with a stopwatch of the time of filling the measuring tank with oil;

- determination of wear of the barrel bore according to the calibration schedule.

The disadvantages of this method include the complexity of carrying out the entire complex of work in the field to measure wear in a given section of the trunk by moving the measuring cylinder, as well as high labor intensity and time consuming in carrying out these works.

The prototype of this technical solution is a method for automatically determining the correction for wear of the bore of an artillery gun in the muzzle velocity of the projectile during ballistic preparation of firing (patent RU 2327944 for the invention application: 2006135598 IPC F41G 3/12 (2006.01) published: 27.06.2008 Bull. No. 18) .

The method for automated determination of the correction for wear of the bore of an artillery gun in the initial velocity of the projectile during ballistic preparation of firing includes the following operations: a gas flow sensor is installed in the wedge of the gun breech, the hermetic volume of the charging chamber is determined by supplying gas to the chamber through the gas flow sensor, the signal is read in an automated mode from gas flow sensor, the value of which is proportional to the volume of the charging chamber and the wear of the bore, and take this value into account when calculating the correction for wear of the bore in the muzzle velocity of the projectile.

The work of the prototype is illustrated in the figure (Fig. 3).

According to the invention, a gas flow sensor 20 is installed in the wedge of the bolt 18 with the striker 19. When the projectile 21 is sent into the channel of the rifled barrel 1 and the wedge of the bolt is closed, the charging chamber will be a sealed volume that can withstand a pressure of at least 15 MPa. Gas (air, etc.) is supplied to this volume through the gas flow sensor, the supply of which stops when a certain pressure is reached, and a signal proportional to the volume of the charging chamber and the wear of the barrel bore is read from the gas flow sensor, the value of which is automatically taken into account when calculating and introducing an amendment to the initial velocity of the projectile.

The disadvantage of the prototype is also the complexity of the entire complex of works in the field.

The technical objective of the invention is the automated determination of the correction for wear of the bore of an artillery gun during ballistic preparation of firing.

This result is achieved by the method of automated determination of the correction for wear of the bore of the artillery gun barrel in the muzzle velocity of the projectile, followed by the introduction of a correction proportional to the volume of the charging chamber and the gun barrel into the firing preparation system, characterized in that a screen reflecting probing acoustic signals is installed on the muzzle, two sound guides are installed in the wedge of the gun bolt, one of which is used to introduce a probing acoustic signal into the charging chamber and the gun barrel, the frequency of which changes, for example, according to a sawtooth law, and the second sound guide outputs the acoustic signal reflected from the walls of the charging chamber and the gun barrel, determine the maximum resonant frequency of the charging chamber and the gun barrel at which the signal is clearly distinguishable at the noise level and the volume of the charging chamber and the gun barrel is calculated from the maximum resonant frequency using the formula:

с - скорость звука в воздухе; S, L - суммарная площадь отверстий и длина передающего и приемного акустических волноводов, соответственно; n - номер гармоники максимальной резонансной частоты акустического сигнала.Where

c is the speed of sound in air; S, L - the total area of the holes and the length of the transmitting and receiving acoustic waveguides, respectively; n is the harmonic number of the maximum resonant frequency of the acoustic signal.

The figure 4 shows a diagram of the experiments to determine the volume of the charging chamber and the gun barrel. According to the invention, it is proposed to install the flange 4 with the input 22 and output 23 acoustic waveguides in the breech 1 of the barrel. Through the input waveguide 22 from the emitter of acoustic waves 24, a probing acoustic signal is introduced into the charging chamber and the barrel of the gun 1, the frequency of which varies, for example, according to a sawtooth law. The acoustic signal reflected from the walls of the charging chamber and the gun barrel is received by the acoustic wave receiver 25 and sent to the computing module for generating and processing acoustic signals 26. The gun barrel 1 at the muzzle is covered with a screen (flange) 5, which reflects acoustic waves. In this case, the gun barrel, closed on both sides, represents an acoustic resonator in which sound propagates as a longitudinal compression wave, forcing air molecules to move back and forth along the barrel. A standing acoustic wave is formed inside the barrel, the frequency of which depends on the volume of the charging chamber and the barrel. Closed screen 5 air in the barrel resonates at n-frequencies. All harmonics of the gun barrel closed on both sides have nodes at the muzzle and in the breech 1. Resonance frequencies f _{i of} the total volume V ₀ of the charging chamber and gun barrel 1, taking into account the total area - S of the holes of the transmitting 22 and receiving 23 acoustic waveguides and their total length - L, are determined by the formula:

where n is the number of acoustic signal harmonics. Denote:

Taking into account the introduced notation, formula (1) can be rewritten in the form:

The sensitivity of the measuring system will be determined by the ratio df/dV ₀ . Differentiating relation (2), we obtain:

Then the sensitivity of the measuring system will be:

Taking into account that n=f _n /f ₁ we rewrite relation (3) in the form:

As follows from relation (4), the sensitivity of the measuring system is proportional to the number of harmonics of the acoustic signal, that is, the higher the measured resonant frequency, the greater the sensitivity of the measuring system. To do this, probing acoustic signals are introduced through the acoustic waveguide 22, the frequency of which changes, for example, according to a sawtooth law and the maximum resonant frequency of the charging chamber and the gun barrel is determined, at which the signal is clearly distinguishable at the noise level. Having measured the maximum resonant frequency of the gun cavity f _max , its volume is determined by the formula:

с - скорость звука в воздухе; S, L - суммарная площадь отверстий и длина передающего и приемного акустических волноводов, соответственно; n - номер гармоники максимальной резонансной частоты акустического сигнала.Where

c is the speed of sound in air; S, L - the total area of the holes and the length of the transmitting and receiving acoustic waveguides, respectively; n is the harmonic number of the maximum resonant frequency of the acoustic signal.

In the second stage, the projectile is sent into the channel of the rifled barrel and the wedge of the shutter is closed, the maximum resonant frequency of the charging chamber is determined and its volume V _c is calculated.

Figure 5 shows a diagram of the experiments to determine the volume of the charging chamber. This experiment differs from the first one in that projectile 7 is sent into the channel of the rifled barrel and the bolt wedge is closed, the resonant frequencies of the signals reflected from the walls of the charging chamber are determined.

New features that have significant differences in method are the following set of actions:

1. The gun barrel at the muzzle is closed with a screen (flange) that reflects acoustic waves back into the gun barrel and charging chamber;

2. Acoustic signals are sent along the waveguide, the frequency of which changes, for example, according to a sawtooth law, excite standing acoustic waves (resonances) at the natural frequencies of the charging chamber and the gun barrel (resonator);

3. A number of resonant frequencies of acoustic signals are received through the acoustic waveguide, the maximum resonant frequency of the charging chamber and the gun barrel is determined at which the signal is clearly distinguishable at the level of noise reflected from the walls of the charging chamber and the gun barrel;

4. According to the selected maximum resonant frequency f _max, the total volume of the charging chamber and the barrel of an artillery gun is calculated:

5. The projectile is sent into the channel of the rifled barrel and the bolt wedge is closed, the maximum resonant frequency of the charging chamber is determined, at which the signal is clearly distinguishable at the level of noise reflected from the walls of the charging chamber:

So, for example, for a 152-mm 2C5 gun, the length of the charging chamber is L _to = 990 mm, and the diameter of the guide disk is D _to = 161.3 mm. The elongation of the charging chamber for the transfer of the barrel from the 1st category to the 2nd is normalized [6] and is ΔL=35 mm.

In this case, the volume of the charging chamber will be:

, резонансные частоты акустических волн будут:Assuming that the total length of the waveguides is L=20 cm=0.2 m, and their diameter is d=0.01 m, and the area S=0.0089 m ² , the ratio will be

, the resonant frequencies of acoustic waves will be:

That is 117.234……1172 Hz.

In this case, the sensitivity will be:

That is, when the volume of the charging chamber changes by 0.00715 m ³ , the resonant frequencies of acoustic waves will change by: 2.07; 8.28; 18.63; 33.12; 51.75 Hz.

Thus, the use of the proposed invention makes it possible to determine:

• The total volume of the charging chamber and the barrel of an artillery gun;

• the volume of the charging chamber.

Information sources:

1. Rules for firing and fire control of artillery. Division, battery, platoon, gun. PS and UO-96. Part 1. - M.: Military publishing house, 1966. - 375 p.

2. Firing tables for flat and mountainous conditions of the 152-mm howitzer 2A65 and the 152-mm self-propelled howitzer 2S19. TS RG No. 187. - M.: Military publishing house. 1994. - 760 p.

3. Patent RU 2206042 (MPK ⁷ F41G 3/12) dated 06/10/2003.

4. Patent RU 2368885 (MPK G01N 3/56, G01B 13/12, F41A 31/02) dated 27.09.2009 Bull. No. 27.

5. Patent RU 2327944 (IPC F41G 3/12) dated June 27, 2008 Bull. No. 18.

Claims (5)

1. A method for automatically determining the correction for wear of the bore of an artillery gun during ballistic preparation of firing, which consists in measuring the volume of the charging chamber and the gun barrel, followed by introducing an amendment proportional to the volume of the charging chamber and the gun barrel into the firing preparation system, characterized in that on the muzzle a screen is installed in the section that reflects probing acoustic signals, two sound guides are installed in the wedge of the gun shutter, one of which is used to introduce a sounding acoustic signal into the charging chamber and the gun barrel, the frequency of which changes, and the second sound guide outputs the acoustic signal reflected from the walls of the charging chamber and the gun barrel signal, the maximum resonant frequency of the charging chamber and the gun barrel is determined, at which the signal is clearly distinguishable at the noise level, and the volume of the charging chamber and the gun barrel is calculated from the maximum resonant frequency using the formula:

Where

c is the speed of sound in air; S, L - the total area of the holes and the length of the transmitting and receiving acoustic waveguides, respectively; n is the harmonic number of the maximum resonant frequency of the acoustic signal. 2. The method according to claim 1, characterized in that the projectile is sent into the channel of the rifled barrel and the wedge of the shutter is closed and its volume is calculated from the maximum resonant frequency of the charging chamber. 3. The method according to claim 1, characterized in that the frequency of the probing acoustic signal changes according to a sawtooth law.

Images