EPNM 2010 Detonation Chambers for Synthesis of Nanodiamonds

EPNM -2010 Detonation Chambers for Synthesis of Nanodiamonds and Another Explosive Technologies A. F. Cherendin, V. G. Galutsky, K. V. Kulik, Yu. P. Meshcherjakov*, A. A. Pikarevsky, O. I. Stojanovsky Design and Technology Branch of Lavrentyev Institute of Hydrodynamics SB RAS, Tereshkovoi Street 29, 630090 Novosibirsk, Russia * ura@kti-git. nsc. ru 1/17

EPNM -2010 Introduction Designing of industrial detonation (explosion) chambers with a long service time meets certain difficulties. Presently there is no comprehensive engineering method for reliable calculation of dynamic stresses in different points of chamber body with arbitrary shape. Different numerical methods concerning the dynamic loading of structures need to be verified experimentally. If to analyze the published works, next conclusions can be made. In [1] only ideal shapes like sphere and cylinder are considered and derived formulas are suitable for the preliminary estimations only. Some investigations show that stresses can differ substantially (in 2 – 2. 5 times) in different points of a chamber body [2, 3]. The other works also have shown the existence of stress concentration in a chamber shell during the explosive loading [4 -6]. 1. Demchuk A. F. , Isakov V. P. Metallic detonation chambers. – Krasnoyarsk: publishing of Krasnoyarsk University, 2006 2. V. V. Adishev, V. M. Kornev. On calculations of explosion chamber shell //Combustion, Explosion, and Shock Waves (Fizika Goreniya i Vzryva). 1979, vol. 15, No. 6, p. 108 -114. 3. A. I. Abakumov, V. V. Egunov, A. G. Ivanov , et all. Calculating-and-Experimental Investigation of Deformation in Explosion Chamber // Journal of Theoretical and Applied Mechanics. 1984, No. 3, p. 127 -130. 4. V. M. Kornev, V. V. Adishev, A. N. Mitrofanov, V. A. Grekhov. Experimental investigation and analysis of explosion chamber shell vibrations // Combustion, Explosion, and Shock Waves (Fizika Goreniya i Vzryva). 1979, vol. 15, No. 6, p. 155 -157. 5. V. V. Silvestrov , A. V. Plastinin, N. N. Gorshkov, O. I. Stoyanovsky. Response of real explosion chamber shell on inner pulse loading // Combustion, Explosion, and Shock Waves (Fizika Goreniya i Vzryva). 1994. No. 2, p. 95 -102. 6. V. V. Silvestrov , A. V. Plastinin, N. N. Gorshkov. Influence of explosive charge surrounding media on a response of explosion chamber shell // Combustion, Explosion, and Shock Waves (Fizika Goreniya i Vzryva). 1994. vol. 30, No. 2.

Introduction EPNM -2010 In this presentation we show the problem of stress concentration is considered in DTB of LIH with the use theoretical calculations and experimental measurements of stresses arising in a chamber shell. Examples of detonation chambers produced in DTB of LIH are given 2/17

Strain measurement technique numerical calculation Detonation Chamber Block board data collection (Switching card, Configuration block, PSU, Data collection board: 64 channels, scan rate 3 MHz ) Personal PC 3/17

Strain measurement technique and numerical calculation II • Coefficient of strain sensor sensitivity – 183± 3% • Resistance of strain sensors – 10 kΩ • The temperature dependence of the coefficient of strain sensor sensitivity– 0. 29%/°С • Time period of studied process – 10 -20 ms • Measurement error – less than 10% Results of strain measurements are compared with numerical calculation results. These calculations are usually made at the stage of chamber design. Numerical calculations are performed using one of the modifications of finite element method developed by Y. P. Mesheryakov *. Boundary conditions : The pressure Р=0 at the outer boundary of the shell The specific impulse J is applied at the inner boundary of the shell *Y. P. Meshcheryakov, N. M. Bulgakova. Thermoelastic modeling of microbump and nanojet formation on nanosize gold films under femtosecond laser irradiation. Appl. Phys. A, 2006, v. 82, pp. 363 -368. 4/17

Testing of the KIP-02 detonation chamber (example of chamber designing using calculation+measurement approach) List of simbols «r» - longitudinal axis of the sensor lies in the cross sectoin plane of shell «f» - the axis of the sensor which is located perpendicularly to the «r» direction 1 r, 9 r - sensors located at the chamber’s poles With the help of the sensor 7 the greatest stress in a cylindrical shell was measured. With the help of other sensors №№ 2, 3, 4, 5, 6, 8 the stresses were measured at the specific points of chamber body. In KIP-0. 2 chamber stress concentration was decreased substantially 5/17

Determination of equivalent stresses In compliance with measured deformations εr(t) и εf(t) , with main directions r и f, stressstrained state was determined by formulas : σr = E(εr + μ εf)/(1 - μ), σf = E(εf + μ εr)/(1 - μ); Equivalent stress : σэ=( σr² + σf² - σr·σf)¹′² Sperical air-blast impulse: J=2ρ0·r(2 Q)/3 R². ρ0 - charge density, r - sperical charge radius , m – charge mass, Q - specific heat energy Peak stress at point 9(r) according to (Мещеряков Ю. П. , Стояновский О. И. Расчет максимальных напряжений в металлических дисках, возникающих в результате воздействия импульсных нагрузок. / Известия Волг. ГТУ № 3 (41), Волгоград, 2008, 144 с. ) (σ r, u)мах. =1. 24·J·a 0·r/2 h², r - disk radius, a 0 - sound speed in metal, h – disk thickness, J - specific impulse 6/17

Dependence of stress in the cover of the chamber on the mass of explosive charge If the charge mass is m = 0. 2 kg than calculated stress in the center of the cover is (σr, u)мах. =115 MPa. Measured value is σэ=101 MPa. The difference between the measured values was 14%, that under the made assumptions and measurement errors can be considered to be satisfactory. 7/17

Dependence of stress in the chamber bottom on the mass of explosive charge Calculated value sэ in the point 1(r) obtained by finite element method exceed the measured value by 10%. In spite of the fact, that there was made the increasing of the bottom thickness (1. 75 times more comparing with ellipsoid thickness), stresses are still maximum for shell 8/17

Dependence of stress in the chamber bottom on the mass of explosive charge(edge of the thickness change , point 2) The purpose of measuring stress in point 2(r, f) was to made sure that the thickness decrease on the edge of the disc didn’t lead to stress increase above the legitimate value. Values of the hoop stresses σf are less by 10 -25 MPa against to largest in this point radial stresses σr and equivalent stresses σэ are between of them what indicates that the maximum stress values σr and σf take place when the corresponding waves of the shell oscillation does not in antiphase. 9/17

Superimposition of the sensors data 7(r), 7(f). Stress dependence on charge mass (point 7) 10/17

Equivalent stresses in point 7(r, f) One can see the typical oscillation of amplitudes - the superposition of oscillations leads to a periodic increase in the amplitudes on the background of the waves attenuation. Distinctly seen 5 such amplitudes with period T=1. 7·10 -4 s. Between them we can see about 10 oscillations with lesser amplitude and period is about T=1. 7·10 -4 s, which correspond to wave-length L= T· a= 0. 85 m (here a= 5·103 m/s – sound speed), i. e. chamber’s body length in longitudinal section between flange and disc. One can suppose, that there is the oscillation superposition at «r» and «f» dimensions with close frequencies 11/17

Stress in point 6 (r, f) compared with calculated value in point 6(r, f) 12/17

Equivalent stresses at specific points of chamber body 13/17

Conclusion Analysis of the stress-strained state of the detonation chamber “KIP-02” shows: 1. Maximum stresses arise on the poles of the cylindrical (short cylinder) detonation chamber and in the central section of the cylindrical shell. Despite the fact that there is the thickening in the center of the elliptic bottom, which thickness at 1. 75 times more than thickness of the cylinder, stress in the center reaches 150 MPa, that 1. 5 times more than stress in the lock’s cover and in the middle part of the cylinder. 2. The results of numerical calculations of the stresses were obtained ( without product pipeline) for the points of elliptical bottom and poles of cylindrical chamber. The calculated data is reasonably well approved by the results of measurements. 3. Investigations of the stress condition of the shell near the orifice, thickened bottom disc and in the place where the cylinder runs into the ellipsoidal head showed that these particularities led to rising of stress values not more than 25%. Maximum stress near the product pipeline is in the point, located more closer to chamber pole. 14/17

Industrial detonation chamber "Alpha-2» designed for production of diamond-graphite product by explosion 1–chamber’s body; 2–cover; 3–charge; 4–tap; 5–container; 6–chassis; 7–filter; 8–pipe line; 9–container; 10–service area. 15/17

Specification of the detonation chamber "Alpha-2" Chamber type – Cylindrical vertical with elliptic bottom Chamber’s overall dimensions, mm: height - 4505 bottom - 2000 x 2500 Chamber’s body mass, kg - 6800 Chamber’s inner volume, м³. -2 Maximum charge mass (TNT equivalent), kg -2 Work cycle time, min - 10 -15 16/17

Explosive chamber KV-0. 2 Camber mass 1. 3 t, overall sizes 1800 x 1200 x 1630 mm

Explosive chamber DVK-0. 2 Chamber mass 2. 7 t, Overall sizes 2185 х 1630 х 2150 mm. Designed for investigation of detonation process using synchrotrone radiation

Laboratory explosive chambers

Explosive chamber KIP-0. 2 Chamber is made from stainless steel. It is used in experiments on explosive synthesis of ultrafine diamonds Chamber mass 0. 85 t Overall sizes 1030 х 850 х 1400 мм

Explosive chamber for 2 kg HE Designed for explosive working of materials. Can be used for utilization of explosives. .

Explosive chamber for 2 kg HE Chamber sealing system eliminates outflow of detonation products and permits evacuation of air and filling of chamber volume with desired gas.

Explosive chamber KVG-8 Chamber mass 48 t Overall dimensions 16360 x 2200 x 2460 мм.

Explosive chamber KVG-16 Chamber mass 76 t , Overall sizes 27210 x 2200 x 2460 mm

Explosive chamber KVG-16 Chamber consists of massive body of 13 m in length and 1. 76 m in diameter. Work table of 10 m in length moves on rails. Explosive charge mass 2 kg per 1 meter. Designed firstly for explosive hardening of railway crossings. Can be used for utilization of explosives.

Explosive chamber KVG-16 Chamber was supplied to Chech Republic and was used for utilization of pyrotechnic substances. During approximately two years 15 thousand explosions were made and 300 t of pyrotechnic materials were utilized. The slide is presented by OZM Company

Thank your for your attention! 17/17