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14EXPERIMENTAL STUDY OF THE SOIL CRUST DESTRUCTION
MECHANISM
Rasuljon Tojiyev Nargizaxon Rajabova
Ferghana Polytechnic Institute
ABSTRACT
The article provides a study by the VSK-5 camera to visualize the process of destruction of the soil crust from the impulse impact of a shock wave by a gas-dynamic flow of detonation products generated by the working body of the detonation wave generator (DWG).
Keywords: crust, explosion, destruction, zone, impulse, force, shock wave, source, gas dynamics, capacitor bank, lamp.
Introduction:
The mechanism of soil crust destruction when exposed to it by a short-term impulse of a gas-dynamic type force (an air shock wave followed by a high-speed, supersonic gas flow). There is no information on the role of the shock wave in destruction, on the distribution of the fractions of total destruction, on the size of the destruction zone, etc.
The question of the choice of the method of expiratory and follow-up was quite problematic. The problem is associated with the lack of developed research methods for the case of impulsive (explosive) loading and the practical lack of information about the physical and mechanical soil crust under such loading (under dynamic conditions).
For this reason, the research was carried out in two ways. The first is based on the visualization of the process by means of high-speed filming (VSK-5 camera, shooting speed 23000 frames / sec) without highlighting shock waves in the photographic recording. Here, as it were, the macroparameters of the destruction process were determined, namely, the selection of the phases of destruction, the determination of the rate of destruction, and the determination of the size of the destruction zone. Due to the limitations of the method of high-speed photographic registration in terms of destructive ability and the difficulty of eliminating the effect of dustiness on the quality of photographic recording, it was not possible to record deformations and the appearance of discontinuities in the object under study. Therefore, the second method was applied -the method of recording the process parameters on photographic film with the illumination of the object under study with laser radiation. The results of these studies are summarized below.
For example:
The purpose of the study is to visualize the process of destruction of the soil crust from the impulse impact of the shock wave and the gas-dynamic flow of detonation products generated by the working body of the detonation wave generator (DWG) using the VSK-5 camera;
- determination of the maximum thickness of the crust, amenable to gas-dynamic destruction.
The studies were carried out on a specially created stand according to the scheme with an attached gas conduit using gasoline-filling mixtures.
The GDV generator (Figure 1) included an ignition chamber (1) with a check valve assembly (2) and a spark plug (3), sections (4), a turbulator (5), a booster pipe (6) and an outlet nozzle (7) [1].
An engine with a ZIL-131 was used as a source of the fuel-air mixture, one cylinder block of which was operating in compressor mode.
The soil crust was formed in special boxes with at least one transparent wall as follows:
- the soil was poured into the box for 2/3 of its volume;
- watering the soil with water;
- drying the soil in a natural way for several days.
The crust was formed on the soil from the fields of the Altyaryk district of the Fergana region.
A schematic diagram of the further experiment is shown in Fig. 1.
Fig. 1. Experiment layout
The working body was mounted on special mounting elements in such a way that its outlet nozzle (outer diameter 46 mm, inner diameter 25 mm) was placed vertically in the volume of the box free from soil in the immediate vicinity of the transparent wall. At the same time, a given distance from the outlet cut of the nozzle to the soil crust was maintained.
During the experiment, the soil crust was subjected to a single gas-dynamic effect, as a result of which a notch was formed in the crust.
The results of studies on the thickness of the crust being destroyed are summarized in Table 1.
Table 1
Experiment №. 1 2 3 4 5 6
Peel thickness - (mm) 35 150 110 54 45 50
Distance from the nozzle cut to the crust 20 20 15 20 15 30
- (mm)
Digging depth - N (mm) 100 20 25 90 80 90
Recess diameter - D (mm) 95 110 100 90 100 200
Penetration - / + / crust + - - + + +
In experiments №. 2; 3, a threefold impact on the crust was carried out, but the dimensions of the recess did not change significantly (without changing the distance from the nozzle cut to the crust).
In the course of the experiments, the process of destruction of the soil crust was filmed using a high-speed video camera VSK-5. The shooting speed was 23,000 frames per second. Frame size 16x22 mm.
Number of frames 7072, time interval between frames = 43.5 microseconds, shooting time = 3x10-3 sec. The high-speed filming scheme is shown in Fig. 2.
Fig. 2. High-speed filming scheme
1-speed camera VSK-5; 2-capacitor bank of the UIG-IM installation; with a capacity of 4500 microfarads; 3-installation UIG-IM; 4-digital oscilloscope S9-8; 5-photodiode FD-2; 6-piezoelectric sensor .HX-610; 7-outlet DWG nozzle; 8-pole power supply; 9-emitter follower on the K 544 UDI microcircuit; 10-soil in containers with transparent walls; 11-pulse lamp; 12-mirror reflector.
The light source was a pulsed xenon lamp (11) with a reflector (12). The source of electric energy of the lamp (11) is the capacitor bank (2) of the UIG-IM laser setup (3). When the detonation wave passes in the output section of the DWG (7) near the LKh-610-type piezoelectric sensor (6), an electrical signal is induced at its output, which, having passed the emitting follower (9), assembled on the K 574 UDI microcircuit, starts the UIG-IM setup and a digital oscilloscope S6-8 (4). With a delay of about 10-3 seconds relative to the external sync pulse (a), the unit (3) generates a high-voltage pulse with an amplitude of 50-60 KV, which breaks through the lamp (11), and then the capacitor bank (2) is discharged through the discharge channel, which leads to a powerful flash Sveta. Discharge energy 35 KJ, the duration of an intense light flash is several milliseconds (35). The duration of the delay of the light flash relative to the LH-610 sync pulse is determined by the speed of the detonation wave and the distance from the sensor (6) to the ground surface.
Part of the sync pulse (6) is fed to the external trigger connector of the C9-8 oscilloscope (4); an electrical signal from the photodiode (5) is supplied to the input of one of the oscilloscope channels, which allows you to adjust the delay in the range from 0.02 ms to 12 ms.
To fine-tune the synchronization of the moment of impact on the crust of a shock wave from the SCS survey period, 14 model surveys were carried out without a crust. As a result of the scatter of parameters, a total of 12 experiments were carried out to obtain 6 valid experiments (see Table 2).
Figure 3 shows a series of frames of the cinematic process
Fig. 3, c. T = 0.51 m / s Fig. 3, d. T = 0.85 m / s
Fig. 3, e. T = 1.53 m / s Fig. 3, f. the result of experiment №. 4
Destruction of the crust by a detonation wave and detonation products (experiment No. 4), including images of the undisturbed state of the soil.
The image is reduced by 3.5 times, the numbers under the photographs indicate the moments of registration of the corresponding frame relative to the last undisturbed image of the crust and soil before the impact.
The exact value of the time interval between adjacent frames (34 msec) was determined by decoding the time of one revolution of the VSK-5 camera mirror recorded in the binary code.
Let's analyze the experimental results.
All cinematographic images of the process of impact on the crust showed three characteristic color zones in the crater area. Schematically it looks like this:
Fig. 4. Crater diagram
Processing of cinematograms according to the speed of movement of the boundaries of 3 zones is presented in the tables (example):
Table 2
The rate of crater formation along the primary circuit (in the pictures - the dark zone)
tabe mls 0.034 0.17 0.51 0.85 1.19 1.53 1.87 2.18
At1 mls 0.034 0.136 0.34 0.34 0.34 0.34 0.34 0.31
h1 mm 9 9,7 10.4 13 15.5 16 17 17.7
âhi mm 0 0.7 0.7 2.6 2.5 0.5 1 0.7
Ah1 mm - 6.79 7.28 33.8 38.75 8 17 12.39
Vhi = ^ mm / mls 50 21.4 10 11.4 23.5 5.0 4.0
Vh1, m / s 50 21.4 10 11.4 23.5 5.0 4.0
Table 3
The rate of crater formation along the second circuit
tabe mls 0.034 0.17 0.51 0.85 1.19 1.53 1.87 2.18
At2 mls 0.034 0.136 0.34 0.34 0.34 0.34 0.34 0.31
h2 mm 17 19.8 21 21.5 22 23.5 24 24
A h2 mm 0 2.8 1,2 0.5 0.5 1.5 0.5 0
A h2 mm 8.57 3.67 1.53 1.53 4.59
j, Ah2K , Vh2 =-mm / h2 At mls 62.2 10.7 4.5 4.5 13.5 4.5 0
Vh2, m / s 62.2 10.7 4.5 4.5 13.5 4.5 0
The graph corrected for the gap between the pipe and the surface of the cake in the initial period is shown in Figure 3.10. It is the dark zone in the images that we take for the crater.
Table 4
The rate of crater formation along the third contour
tabe mls 0.034 0.17 0.51 0.85 1.19 1.53 1.87 2.18
At mls 0.034 0.136 0.34 0.34 0.34 0.34 0.34 0.31
h3 mm 21 21 23 25 26 28 18.5 29 29.5
h3 mm 64.26 64.26 70.38 76.5 79.56 85.68 87.21 88.74 90.2
A h3 6.12 6.12 3.06 6.12 1.53 1.53 1.53
Vh3, mm / mls 45 18.4 9.2 18.4 3.6 3.6 4.9
Vh3, m / s 45 18.4 9.2 18.4 3.6 3.6 4.9
For this example, K = 3.06 is the coefficient of transition from linear dimensions in photographs to full-scale dimensions.
The rest of the cinematograms give results close to those given in the example. Average values in the initial period Vh1 = 60 m/s, Vh2 = 50 m/s, Vh3 = 40 m/s, average speed on three circuits Vav = 50 m/s...
The fact of the variable rate of crater formation is obvious. To analyze this fact, let us turn to the graph of the load (change in the pressure pulse) on the surface of the crust created by the detonation generator (see Figure 2.3 in the theoretical calculation of the crust destruction process.). It is clear that the variable (decreasing) velocity of the crater formation fully correlates with the character of the decreasing impulse of the acting force.
The second result of this part of the experiments, the time of the entire process of destruction lies within 2 ms (0.002 s).
Estimation of the time of the process of expiration of detonation products from the working body according to the formula:
tz = 3,5^ L > ^
°d.p
where: 3.5 - coefficient depending on the thermodynamic properties of the fuel and
oxidizer of the combustible mixture;
Lwb - the length of the working body;
Cd.p. Is the speed of sound in detonation products.
3,15m/s h = 3,5 ^ = 0,0148s L 800m
According to K.P. Stanyukovich's estimates [2], the bulk of the detonation products expire in the initial period (15% of the total expiration time), i.e. in our case for 0.0022 sec.
Thus, the experiment and the theoretical estimate are in good agreement.
The third result is the maximum thickness of the crust being destroyed by the working body by the experiments.
It is necessary to note the feature recorded in all experiments - an increase in the rate of destruction (crater formation) in a period of about 1.5 ms. There is no explanation of this fact in the theoretical part of the calculation of destruction, and objectivity requires paying attention to this, in our opinion, this fact can be attributed to the restructuring of the outflow of detonation products from the tube into the atmosphere during this period. The outflow is reconstructed from supersonic to subsonic (the so-called transonic flow region). This period does not flow smoothly; the flow switches from sonic to subsonic and vice versa several times. Accordingly, the expiration appears. Apparently, such an oscillatory regime leads to a certain increase in the removal of soil mass from the crater. This explanation is a hypothesis and does not claim to be an exhaustive proof.
This stage of the study also showed that the high-speed camera VSK-5 does not allow recording deformations, cracking and fragmentation of the crust during its destruction. For this reason, additional studies using laser illumination and a faster camera "IMACON-790". This stage of research is more laborious with the use of more sophisticated experimental equipment. In the following articles, we will move on to presenting its content.[3]
As a result of joint theoretical and experimental studies, it is possible to formulate the main indicators of the mechanism of destruction of the soil crust by the action of GDSC:
Conclusion:
The load on the crust, which consists of a shock wave and a stream of detonation products, acts simultaneously as a single complex.
The impact occurs at supersonic speed, both in relation to the speed of sound in air and in relation to the speed of sound in soil. Consequently, in a certain zone (according to theoretical calculations, the radius of the zone is about 60 mm), impact fracture occurs in the crust with the formation of microcracks.
Micro-fractures without noticeable deformation of the crust and without the formation of visible cracks. The duration of the first period is of the order of 350 ^s.
REFERENCES
[1] Rasuljon, T., Azizbek, I., & Bobojon, O. (2021). Studying the effect of rotor-filter contact element on cleaning efficiency. Universum: технические науки, (6-5 (87)), 2832.
[2] Rasuljon, T., Akmaljon, A., & Ilkhomjon, M. (2021). SELECTION OF FILTER MATERIAL AND ANALYSIS OF CALCULATION EQUATIONS OF MASS EXCHANGE PROCESS IN ROTARY FILTER APPARATUS. Universum: технические науки, (5-6 (86)), 22-25.
[3] Isomiddinov, A., Axrorov, А., Karimov, I., & Tojiyev, R. (2019). Application of rotor-filter dusty gas cleaner in industry and identifying its efficiency. Austrian Journal of Technical and Natural Sciences, (9-10).
[4] Тожиев, Р. Ж., Ахунбаев, А. А., & Миршарипов, Р. Х. (2018). Сушка тонкодисперсных материалов в безуносной роторно-барабанном аппарате. Научно-технический журнал ФерПИ,-Фергана, (2), 116-119.
[5] Мадаминова, Г. И., Тожиев, Р. Ж., & Каримов, И. Т. (2021). Барабанное устройство для мокрой очистки запыленного газа и воздуха. Universum: технические науки, (5-4 (86)), 45-49.
[6] Rasuljon, T., Azizbek, I., & Bobojon, O. (2021). Studying the effect of rotor-filter contact element on cleaning efficiency. Universum: технические науки, (6-5 (87)), 2832.
[7] Ахроров, А. А. У., Исомиддинов, А. С., & Тожиев, Р. Ж. (2020). ГИДРОДИНАМИКА ПОВЕРХНОСТНО-КОНТАКТНОГО ЭЛЕМЕНТА РОТОР-ФИЛЬТРУЮЩЕГО ПЫЛЕУЛОВИТЕЛЯ. Universum: технические науки, (8-3 (77)).
[8] Tojiev, R., Ortikaliyev, B., & Tojiboyev, B. (2019). Improving selecting technology of raw materials of fireproof bricks. Тенденции и переспективы развития науки и оброзования в условиях глобализации. Украина, 27(46), 606-609.
[9] Тожиев, Р. Ж., Каримов, И. Т., & Исомидинов, А. С. (2020). Чанглигазларнихулусулдатозаловчикурилманисаноатдакуллашнингилмий-техник
асослари: Монография. ФарПИ" Илмий-техника" журналинашриётбулими-Фаргона, 91.
[10] Тожиев, Р. Ж., & Ортикалиев, Б. С. (2019). ОЛОВБАРДОШ ЕИШТ ИШЛАБ ЧЩАРИШДА ХОМ АШЁЛАРНИ САРАЛАШ ЖАРАЁНИНИ ТАДЖИК КИЛИШ. Журнал Технических исследований, (2).
[11] Исомидинов, А. С., Тожиев, Р. Ж., & Каримов, И. Т. (2018). Дул усулда чангли газларни тозаловчи роторли курилма. Фаргона политехника институтининг илмий-техник журнали.-Фаргона, (1), 195-198.
[12] Tojiyev, R. J., Ortiqaliyev, B. S. O. G. L., Abdupattoyev, X. V. O., & Isomiddinova, D. I. J. Q. (2021). DONADOR-SOCHILUVCHAN MAHSULOTLARNI SARALASHDA SM-237A MARKALI MASHINALARINI O 'RNI. Scientific progress, 2(2), 1378-1381.
[13] Tojiev, R. J., & Sadullaev, X. M. (2018). DETERMINATION OF THE ANGLE OF CAPTURE OF THE CRUSHING CHAMBER OF A CONE CRUSHER, TAKING INTO ACCOUNT THE KINEMATICS OF THE ROLLING CONE. Scientific-technical journal, 22(3), 55-60.
[14] Sadullaev, X., Tojiyev, R., & Mamarizaev, I. (2021). EXPERIENCE OF TRAINING BACHELOR-SPECIALIST MECHANICS. Барцарорлик ва Етакчи Тадцицотлар онлайн илмий журнали, 1(5), 116-121.
[15] Tojiyev, R., Ortiqaliyev, B., & Sotvoldiyev, K. (2021). IMPROVING THE DESIGN OF THE SCREED FOR FIREBRICKS USING SOLIDWORKS. Барцарорлик ва Етакчи Тадцицотлар онлайн илмий журнали, 1(5), 91-99.
[16] Tojiyev, R. J., Akhunbaev, A. A., & Mirsharipov, R. X. (2021). RESEARCH OF HYDRODYNAMIC PROCESSES WHEN DRYING MINERAL FERTILIZERS IN DRUM DRYERS. Scientific-technical journal, 4(4), 10-16.
[17] Ахунбаев, А. А., Ражабова, Н. Р., & Вохидова, Н. Х. (2020). Исследование гидродинамики роторной сушилки с быстровращающимся ротором. Экономика и социум, (12-1), 392-396.
[18] Тожиев, Р. Ж., Ахунбаев, А. А., & Миршарипов, Р. Х. (2018). Сушка тонкодисперсных материалов в безуносной роторно-барабанном аппарате. Научно-технический журнал ФерПИ,-Фергана, (2), 116-119.
[19] Tojiyev, R. J., Akhunbaev, A. A., & Mirsharipov, R. X. (2021). RESEARCH OF HYDRODYNAMIC PROCESSES WHEN DRYING MINERAL FERTILIZERS IN DRUM DRYERS. Scientific-technical journal, 4(4), 10-16.
[20] Дусматов, А. Д., Хурсанов, Б. Ж., Ахроров, А. А., & Сулаймонов, А. (2019). ИССЛЕДОВАНИЕ НАПРЯЖЕННО ДЕФОРМИРОВАННОЕ СОСТАЯНИЕ ДВУХСЛОЙНЫХ ПЛАСТИН И ОБОЛОЧЕК С УЧЕТОМ ПОПЕРЕЧНЫХ
СДВИГОВ. In Энерго-ресурсосберегающие технологии и оборудование в дорожной и строительной отраслях (pp. 48-51).
[21] Ergashev, N. A. (2020). DETERMINATION HYDRAULIC RESISTANCE OF DEVICE THAT HAS THE VORTEX FLOW CREATING CONTACT ELEMENT. Austrian Journal of Technical and Natural Sciences, (3-4).
[22] Sadullaev, X., Tojiyev, R., & Mamarizaev, I. (2021). EXPERIENCE OF TRAINING BACHELOR-SPECIALIST MECHANICS. Баркарорлик ва Етакчи Тадкикотлар онлайн илмий журнали, 1(5), 116-121.
[23] Хакимов, А. А., Салиханова, Д. С., & Каримов, И. Т. (2019). Кумир кукунидан брикетлар тайёрлашнинг долзарблиги. Фаргона политехника институти илмий техника журнали.-2019.-№, 23(2), 226-229.
[24] Хакимов, А. А. (2020). Связующее для угольного брикета и влияние его на дисперсный состав. Universum: химия и биология, (6 (72)), 81-84.
[25] Хакимов, А. А., Салиханова, Д. С., & Каримов, И. Т. (2018). Кумир кукунини брикетловчи курилма. Фаргона политехника институти илмий техника журнали.-2018.-№ спец, 2, 169-171.
[26] Алиматов, Б. А., Эргашев, Н. А., & Каримов, И. Т. (2019). Мокрый пылеулавливающий аппарат с прямоточно-вихревыми контактными элементами. Научно-техн. журнал Ферганск. политехн. ин-та, 23(2), 152.
[27] Алиматов, Б. А., Садуллаев, Х. М., Каримов, И. Т., & Хурсанов, Б. Ж. (2008). Методы расчета и конструирования жидкостных экстракторов с пневмоперемешиванием.
[28] Sadullaev, X., Alimatov, B., & Mamarizaev, I. (2021). DEVELOPMENT AND RESEARCH OF A HIGH-EFFICIENT EXTRACTION PLANT AND PROSPECTS FOR INDUSTRIAL APPLICATION OF EXTRACTORS WITH PNEUMATIC MIXING OF LIQUIDS. Баркарорлик ва Етакчи Тадкикотлар онлайн илмий журнали, 1(5), 107-115.
[29] Sadullaev, X., Muydinov, A., Xoshimov, A., & Mamarizaev, I. (2021). ECOLOGICAL ENVIRONMENT AND ITS IMPROVEMENTS IN THE FERGANA VALLEY. Баркарорлик ва Етакчи Тадкикотлар онлайн илмий журнали, 1(5), 100106.
[30] Ализафаров, Б. М. (2020). ECOLOGICAL DRYING OF FINE DISPERSED MATERIALS IN A CONTACT DRYER. Экономика и социум, (11), 433-437.
[31] Ахунбаев, А. А., & Ражабова, Н. Р. (2021). ВЫСУШИВАНИЕ ДИСПЕРСНЫХ МАТЕРИАЛОВ В АППАРАТЕ С БЫСТРО ВРАЩАЮЩИМСЯ РОТОРОМ. Universum: технические науки, (7-1 (88)), 49-52.
