RU2122206C1 - Method determining sensitivity of explosive charge to dynamic action of liquid jet - Google Patents

Abstract

FIELD: study of sensitivity of explosive charges to dynamic loading. SUBSTANCE: in accordance with method there are conducted action of high-speed liquid jet on explosive charge, fixation and recording of dependencies of pressure on time and comparison of obtained dependencies with dependencies obtained in experiments with explosive test charges. Surface of explosive charge is subjected to action of high-speed liquid jet formed under action of plunger forced by powder charge. High-speed liquid jet is run through accelerating nozzle on to sample of explosive. Piezosensor registers pressure formed in blast chamber by reactions taking place. Experiments with detonation of test charges of explosive having various masses lesser than mass of examined explosive charge are carried out in advance. Obtained changes of pressure are recorded by piezosensor. Then obtained dependencies of change of pressure on test charges and examined charge of explosive are compared. EFFECT: increased accuracy of determination of rational and safe modes of washing out of explosives and reduced number of experiments required for it. 4 cl, 2 dwg

Description

 The invention relates to the field of explosives (BB) research, in particular to determining the sensitivity of explosives to the action of high-speed liquid jets, which can be used to determine safe modes for extracting explosives from ammunition bodies to be disposed of, with minimal material and energy costs, and ensuring an easier way to conduct an experiment for any type of explosive.

An analogue of this invention is a method for determining the sensitivity of an explosive to the action of cumulative jets [1], where for the initiation of a detonation process it is necessary to fulfill the conditions
A = ρ _c W $\genfrac{}{}{0ex}{}{\text{2}}{\text{c}}$ d _c > [A],
where ρ _c is the density of the material of the cumulative jet (g / cm ³ );
W _with - the speed of the cumulative jet (km / s);
d _{with the} diameter of the cumulative jet (mm);
[A] = 180 (g / cm ³ • km / s • mm) - threshold value characterizing the sensitivity of the explosive to the action of a cumulative jet.

The disadvantage of this method is, firstly, the presence of a constant [A] on the left side of the dependence, which indicates the impossibility of using it to determine the sensitivity of different types of explosives, in addition, the analyzed approach leads to the neglect of the real properties of explosives and to serious errors in predicting their sensitivity to the beat. Secondly, the complex of parameters ρ _c W $\genfrac{}{}{0ex}{}{\text{2}}{\text{c}}$ d _c is physically unreasonable, since it is valid only for a narrow range of initial conditions, which is not additionally specified. This groundlessness can be argued by the following example: at relatively low speeds, but when the diameter tends to infinity, according to the Held criterion, an explosive process is initiated - this contradicts the physics of real explosive transformations.

 The prototype of this invention is a method for determining the sensitivity of energy materials [2]. The essence of this method is to analyze the output gaseous products obtained by the interaction of a high-speed jet of liquid and explosives in an explosive chamber. The tests are as follows. A portion of the test explosive is installed in a ring, which is fixed in a special sleeve. The plunger, enclosed in a steel casing, is boosted by a powder charge. Under the action of the generated pressure, the fluid is driven through the accelerating nozzle onto the explosive hinge. The gas samples created in the explosive chamber after the interaction of the explosive with a liquid stream are collected after each experiment and analyzed for any reactions using a liquid chromatograph.

 The disadvantage of this method is the complexity of the analysis of the ongoing reactions, in which the amount of nitrite and nitrate ions in the ion chromatograph is estimated.

 In connection with the recent emergence of a particularly important problem of disposing of obsolete and ammunition of ammunition, it is necessary to determine rational modes for extracting explosives from shells with minimal time and guaranteed work safety. In particular, the urgent task is to determine the sensitivity of explosive charges to the action of high-speed liquid jets, which is associated with the use of liquid jets for unloading ammunition (ammunition).

 The objective of the present invention is to increase the accuracy of determining rational and safe modes of leaching of explosives and reduce the number of experiments required for this.

 The problem is solved as follows. Previously, when conducting experiments on detonation of test explosive charges, which have lower masses compared with the explosive under study, the dependence of pressure on time for each explosive test charge is recorded using piezoelectric sensors. The explosive charge studied in the explosive chamber is dynamically affected by a high-speed jet of liquid with predetermined geometric and kinematic parameters, and the dependence of pressure on time is measured and recorded using piezoelectric sensors. The explosive charge sensitivity is judged by the mass of the reacted test explosive charge, which has the closest similar pressure versus time dependence with the dependence of the test sample.

 In order to increase the accuracy of this method during test tests, inert inserts are placed in the blast chamber, the volume of which is equal to the difference between the volume of the test sample and the test sample. Moreover, the discreteness of the change in the mass of the tested explosive charges is selected from the accuracy of determining the sensitivity of the explosive charge to dynamic effects. It is advisable to initiate test charges by heating them to a flash point, for example, by electric current.

 In FIG. 1 schematically shows an installation for implementing this method.

 In FIG. Figure 2 shows a graph of the pressure versus time, allowing a comparative analysis of the obtained pressure dependences over time of the explosive charge under test and test charges.

 The installation for determining the sensitivity of explosives to the action of high-speed liquid jets consists of a base plate 1, a damping plate 2, a cylinder 3 designed to accommodate a charging cartridge 4 with an ignition sleeve 5, a cylinder 6 with a piston 7, an upper plate 8 with an accelerating nozzle located in it 9, an explosive chamber 10, a target 11 with a ring 12 containing an explosive 13 (test or test charge), sensors 14, 15, a pressure plate 16, o-rings 17, 18, 19, a fuel charge 20, a sample of liquid 21. For connection plates 1, 8 and 16 designed s studs 22 in an amount of 4 pcs. The installation is located vertically on the boxing table. Piezosensors for measuring the pressure in the chamber of the charging cartridge are installed in the bore of the cylinder 3. Devices for determining the kinematic parameters of the jet are located in the explosive chamber 10. Position 23 denotes an inert insert for the test charge 13.

 A method for determining the sensitivity of explosives to the action of high-speed liquid jets is implemented as follows. During the combustion of the powder suspension 20, the generated powder gases act on the piston 7 enclosed in the cylinder 6. Under the action of the gases, the piston 7 drives the liquid 21 through the accelerating nozzle 9 onto the explosive substance 13 enclosed in the ring 12. The pressure arising in the explosive chamber 10 during interaction a jet of liquid with an explosive charge is recorded by a piezosensor. Previously, experiments on the detonation of test explosive charges having different masses smaller than the mass of the explosive charge under study are carried out at the same facility. Initiation of test charges is carried out using electric current. The resulting pressure is recorded by the piezoelectric sensor.

 An example implementation of the proposed method.

The explosives tested for sensitivity and test charges have a density ρ = 1.6 g / cm ³ . Changing test charges having different masses (m ₁ = 0.2m _and ; m ₂ = 0.4m _and ; m ₃ = 0.6m _and ; m ₄ = 0.8m _and , where m _and = 3g is the mass of the test charge ), they are affected by electric current, recording the change in pressure over time (dependencies P _t (t) - 1, 2, 3, 4). Then, the explosive charge under study is affected by a liquid jet with a diameter of d = 0.4 mm under a pressure of P = 40 MPa. The time dependence of pressure P _and (t) is recorded and the obtained dependences P _t (t) of test charges are compared with the dependence P _and (t) of the test sample. We determine the amount of reacted explosive charge under study equal to 0.69 g. This result allows us to conclude that the dynamic action of a liquid jet with the above parameters leads to partial initiation of the explosive charge under study (23%).

 The advantage of the proposed method for determining the sensitivity of the explosive charge to the action of high-speed liquid jets is a more efficient way to determine the rational and safe modes of washing the explosives from the PSU cases, without conducting numerous experiments.

Sources of information
1. M. Held. Initiating of Explosives a Multiple of the Physics of Detonation. Exlosivistoffe, 1968, No. 5, p. 98-113.

 2. P. N. Vorsey et al. Initiation of explosives by a liquid stream. / Materials of the VII International Symposium on Jet Cutting Technologies. // Ottawa, Canada, 1984, p. 307-312.

Claims (4)

 1. The method of determining the sensitivity of the explosive charge to the dynamic effect of a liquid jet, which consists in the fact that the test explosive charge placed in the cavity of the explosive chamber is dynamically exposed to a high-speed liquid jet with predetermined kinematic and geometric parameters, characterized in that it is previously in the cavity explosive chamber detonate test explosive charges having different masses smaller than the mass of the investigated explosive charge of a test substance, using piezoelectric sensors register the dependence of pressure on time for each test explosive charge, after which the explosive charge under study is dynamically acted upon by a high-speed liquid jet, pressure dependence on pressure is measured and recorded using piezoelectric sensors, and the explosive charge sensitivity to dynamic action determined by the mass of the reacted test explosive charge having the closest similar pressure time dependence of the test sample.  2. The method according to claim 1, characterized in that when the test charges are detonated, inert inserts with a volume equal to the difference between the volume of the test charge and the volume of the test explosive charge are placed in the explosive chamber.  3. The method according to p. 1, characterized in that the discreteness of the change in the mass of the tested explosive charges is selected from the condition of ensuring the accuracy of determining the sensitivity of the explosive charge to dynamic effects.  4. The method according to claim 1, characterized in that the initiation of test explosive charges is carried out by heating them to a flash point, for example, by electric current.

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