RU2724070C1 - Device for measurement of combustion rate of pyrotechnic mixture of thermal chemical current source - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to devices in which pyrotechnical heating mixtures are used. Device for measuring combustion rate of pyrotechnic mixture of a thermal chemical current source comprises a combustion chamber with a heat pellet arranged therein, a radiation receiver and a multichannel recording device with a timer, combustion chamber is made in the form of a package consisting of an upper plate and a lower plate with holes coated with a heat pellet arranged between the mica gaskets, on the heat pellet with the possibility of initiating its combustion there is an igniting material and a heating element, and between the upper plate and the heat pellet there is an asbestos gasket, the package is made with a compressed force of 1–1.2 kN, the radiation receiver is made in the form of two photodiodes, and the multichannel recording instrument with a timer is made in the form of an oscillograph.

EFFECT: technical result is reduced consumption of time for measurement of combustion speed due to simplification of obtaining signals of passage of the front of burning of specified marks.

1 cl, 1 dwg

Description

The invention relates to the field of devices in which pyrotechnic heating mixtures are used, in particular, thermal HIT.

A device for measuring the burning rate of a sample of solid fuel, containing a sealed combustion chamber, a sample of solid fuel placed in it in an armored cup with two signal metal threads located at a known reference distance from each other in the holes drilled in the sample perpendicular to its axis, is a multi-channel recorder with timer [Sinaev K.I. Laboratory work on internal ballistics. Publishing house of the Kazan Institute of Chemical Technology, 1968, 165 S.].

The disadvantage of the device as applied to the combustion rate of thermal tablets TCIT is the presence of signal metal threads, which complicate the design of the device and make it ineffective.

A device is known for measuring the burning rate of fuel in a solid fuel rocket engine (Patent RU No. 2175741, published 10.11.2001, IPC F23N 5/08 taken as a prototype), containing a combustion chamber with an end-face solid-fuel solid-fuel charge placed in it (we have thermal tablet), a radiation receiver, a photo amplifier and a multi-channel recording device with a timer, moreover, holes are made in the charge, the geometric axes of which are located at known distances from each other and perpendicular to the geometric axis of the charge, microdoses are placed in holes at different radii from the geometric axis of the charge chemical compounds of different alkali group auxiliary elements in a volume of 0.001-0.01 cm ³ , and in different holes a microdose of a chemical compound of the same additional element is placed at the same radius from the geometric axis of the charge, and the free space between the microdoses is filled with an armor compound, line of sight receiver and radiation is combined with the cut-off plane of the nozzle of a solid fuel rocket engine, and a monochromatic filter with a transmission wavelength equal to the wavelength of the saturated central part of the spectral line of one of the n-used auxiliary elements, alkaline group, n-1-beam splitting plates, and a lens are installed in front of the radiation receiver , in the beams reflected from the beam splitting plates, one additional radiation receiver with a monochromatic filter having a transmission wavelength equal to the wavelength of the saturated central part of the spectral line of one of the n-used additional elements of the alkaline group is installed one in each beam, and the outputs of additional radiation receivers are connected through additional photo amplifiers to separate inputs of a multi-channel recording device with a timer.

The disadvantage of the prototype is the excessive complexity of the device in the tasks of thermal HIT, which reduces the reliability of its operation.

The problem with the devices for determining the combustion rate is the complexity of the existing devices, which affects the reliability of their operation, as well as the indication of the points of passage by the combustion front of marks located at a known distance from each other. The present invention is directed to solving this problem.

The technical result of the invention is to reduce the time spent on measuring the combustion rate by simplifying the reception of signals passing the combustion front of the given marks, as well as simplifying the design of the device, which increases the reliability of its operation.

The technical result is achieved by the fact that the device for measuring the burning rate of the pyrotechnic mixture of thermal HIT contains a combustion chamber with a thermal tablet placed in it, a radiation receiver and a multi-channel recording device with a timer, the combustion chamber is made in the form of a package consisting of an upper plate and a lower plate with holes covered with a thermal tablet and placed between the mica pads, a combustible material and a heating element are located on the thermal tablet with the possibility of burning it, and an asbestos gasket is placed between the top plate and the thermal tablet, the package is made with a compressed force of 1-1.2 kN, the radiation receiver made in the form of two photodiodes, and a multi-channel recording device with a timer is made in the form of an oscilloscope.

The bottom plate with holes located so that the thermal tablet covers them completely serves to fix the distance that the combustion front travels. When the combustion front passes over the hole, the photodiode located opposite it detects a jump in illumination, which the oscilloscope registers as a voltage jump on the photodiode. Voltage surges on two photodiodes occur with a time difference corresponding to the time that the combustion front travels the distance between the two holes of the lower plate. The arrangement of the openings so that the thermal tablet covers them completely also serves to prevent the fixation of the initial and final positions of the combustion front. Mica pads prevent the ingress of combustion products onto photodiodes, and also perform a heat-insulating function. The upper plate serves to create pressure on the thermal tablet, which creates the conditions for measuring the burning rate, corresponding to the tablet operating conditions in the TCIT, which also determines the compression force of 1-1.2 kN. The heating element, which can be used as a nichrome spiral, is designed to initiate combustion by heating the flammable material, which can be used as a pyrotechnic tape igniter. The use of an oscilloscope as a recording device is due to its speed and allows you to record the difference in time to microseconds.

The invention is illustrated in the drawing.

The drawing shows the structural elements of the installation in cross section.

1 - bottom plate

2 - thermal tablet

3 - mica pads

4 - flammable material

5 - asbestos gasket

6 - top plate

7 - photodiodes

8 - heating element

9 - DC power supply

10 - key heating element 8

11 - oscilloscope

12 - combustion chamber made in the form of a package

A device for measuring the burning rate of a pyrotechnic mixture of thermal HIT contains a combustion chamber with a thermal tablet 2 located in it, a radiation receiver and a multi-channel recording device with a timer. The combustion chamber is made in the form of a package 12, consisting of an upper plate 6, a thermal tablet 2, and a lower plate 1 made with holes arranged so that the thermal tablet 2 covers them completely. The lower plate 1 is placed between the mica gaskets 3, on the thermal tablet 2 with the possibility of burning it is located a combustible material 4 and the heating element 8, and an asbestos gasket 5 is placed between the upper plate 6 and the thermal tablet 2. The package 12 is made with a compressed force 1-1, 2 kN, the radiation receiver is made in the form of two photodiodes 7, and the multi-channel recording device with a timer is made in the form of an oscilloscope 11. Flammable material 4, which can be used as a pyrotechnic tape igniter, is initiated from the heating element 8, which can be used nichrome spiral . The heating element 8 is heated by passing current from a direct current power source 9 connected to it using a key 10. Thus, the proposed device has a reliable, less complex design compared to the prototype due to the fact that it does not contain a number of difficult structural elements the inherent design of the prototype, such as an armored thermal tablet and microdoses of an additional element

Assemble a device for measuring the burning rate of a pyrotechnic mixture of thermal HIT as follows. A bag 12, comprising: a bottom plate 1 on which openings are arranged so that the thermal tablet 2 covers them completely, a bottom plate 1 is placed between the mica pads 3; thermal tablet 2, placed between one of the mica pads 3 and asbestos gasket 5, on the thermal tablet 2 place a flammable material 4 and a heating element 8; asbestos gasket 5, over which the upper plate is placed 6. A constant force of 1-1.2 kN is applied to the assembled bag. Opposite each of the openings of the bottom plate 1, photodiodes 7 are fixed and their outputs are connected to the oscilloscope 11.

After that, the key 10 of the heating element 8 is closed, which ensures the combustion of the igniting material 4. The ignition of the material 4 causes the heat of the tablet 2. When the combustion front reaches the hole in the bottom plate 1 closest to the ignition point, a jump is sent from the corresponding photodiode 7 to the oscilloscope 11 voltage. At the moment when the combustion front reaches the next hole, a voltage surge from the next photodiode 7 is supplied to the oscilloscope 11. The speed of the oscilloscope 11 allows you to register the difference in time to microseconds. The time of front movement is determined from the obtained waveform, and then, according to the known distance between the holes in the bottom plate 1, the burning rate is calculated.

An example of the operation of the device. The burning rate of the pyrotechnic mixture was determined in the form of a tablet with a diameter of 35 mm. The distance between the holes of the bottom plate was 25 mm. The time difference between the voltage surges on the photodiodes was 350 ms. The burning rate was determined by the formula:

V = L / T × l000.

V - burning rate of the tablet, mm / s

L is the distance between the LEDs, mm

T - time, s

The burning rate was 73.53 mm / s.

Thus, a reduction in the time required to measure the combustion rate was achieved by simplifying the receipt of signals passing the combustion front of the given marks, as well as simplifying the design of the device.

Claims (1)

A device for measuring the burning rate of a pyrotechnic mixture of a thermal chemical current source, comprising a combustion chamber with a thermal tablet placed therein, a radiation receiver and a multi-channel recording device with a timer, characterized in that the combustion chamber is made in the form of a package consisting of an upper plate and a lower plate with holes coated with a thermal tablet and placed between mica gaskets, a combustible material and a heating element are located on the thermal tablet with the possibility of burning it, and an asbestos gasket is placed between the top plate and the thermal tablet, the package is made with a compressed force of 1-1.2 kN, the receiver radiation is made in the form of two photodiodes, and a multi-channel recording device with a timer is made in the form of an oscilloscope.

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