Gas explosion in a cylindrical tube with a hole on the lateral surface

The aim of this work was to investigate the explosion of propane-air mixture in a cylindrical tube with 20 cm in diameter and 150 cm in length, closed at both ends and having hole on the lateral surface, dimensions and position of which were varied according to conditions of experiments. The study was conducted by numerical simulation within 3D CFD (Computational Fluid Dynamics) models based on a system of fundamental conservation equations applied to problems of gas dynamics, which supplemented by equations describing the propagation of a flame. System of approximating equations was solved by the large-particle method (LPM) developed by Belotserkovskiy O. M. and Davydov Yu. M. This method involves applying the rigid grid, placed in the calculated area and formed from about 90 thousands of the so-called “particles”, through which move the gas flows. Comparison of the results of numerical experiments and previously conducted physical experiments show the adequacy of the mathematical model. As a result of studies it was confirmed the known dependence between the explosion pressure and the diameter of a hole. Furthermore, it was shown that the dependence of explosion pressure on size and position of a hole on the lateral surface is ambiguous. Decrease of the distance between the hole of a smaller size and the source of ignition leads to rising explosion pressure (while increase of the distance leads to its lowering). The abnormal development of explosion in the form of self-oscillation with large amplitude in a certain range of size and position values of a hole was revealed during experiment. This effect is very similar to the “singing flame” phenomenon of Higgins. In conditions of pressure oscillations there were observed the fluctuations of position and size of the flame front. Oscillations lead to significant increase in pressure compared to explosions without oscillations. It should be noted that the possibility of appearance of the self-oscillation mode of explosion is known from the data of physical experiments, but such mode was modeled for the first time. It is known that previous attempt to create such mode using FLACS software was unsuccessful.

газовый взрыв, цилиндр с отверстием, место воспламенения, CFD-модель, метод крупных частиц, “поющее пламя”, давление взрыва, автоколебания, gas explosion, cylindrical tube, CFD models, explosion pressure, large-particle method, “singing flame”, self-oscillation

1. СНиП II-35-76*. Котельные установки. Раздел 3. Объектно-планировочные и конструктивные решения.-Введ. 01.01.1978.-М. : Стройиздат, 1977. URL: http://снип.рф/snip/view/35 (дата обращения: 01.07.2016).

2. EN 14994:2007. Gas explosion venting protective systems. URL: https://webshop.ds.dk/Files/Files/ Products/56150/attachPV.pdf (дата обращения: 01.07.2016).

3. NFPA68. Standard on explosion protection by deflagration venting. 2007 Edition.-Quincy,MA:National Fire Protection Association, 2007. URL: http://gazkhodro.ir/wp-content/uploads/2015/11/ NFPA-68-2007-Standard-on-Explosion-Protection-by-Deflagration-Venting.pdf (дата обращения: 01.07.2016).

4. Molkov V. V., Eber R. M., Grigorash A. V., Tamanini F., Dobashi R. Vented gaseous deflagrations: modelling of translating inertial vent covers // Journal of Loss Prevention in the Process Industries. - 2003. -Vol. 16, No. 5. -P. 395-402. DOI: 10.1016/S0950-4230(03)00066-4.

5. Bauwens C. R., Chaffee J., Dorofeev S. B. Vented explosion overpressures from combustion of hydrogen and hydrocarbon mixtures // International Journal of Hydrogen Energy.-2011.-Vol. 36, Issue 3. -P. 2329-2336. DOI: 10.1016/j.ijhydene.2010.04.005.

6. Helene H. Pedersen, Prankul Middha. Modelling of vented gas explosions in the CFD tool FLACS // Chemical Engineering Transaction.-2012.-Vol. 26.-P. 357-362. DOI: 10.3303/CET1226060.

7. Robert Zalosh. Explosion venting data and modeling. Literature review.-Quincy, MA : Fire Protection Research Foundation, 2008. URL: https://www.nfpa.org/Assets/files/AboutTheCodes/68/ Firexplo/Explosion/Venting/Report.pdf (дата обращения: 25.06.2016).

8. Bradley Derek, Mitcheson Alan. Mathematical solutions for explosions in spherical vessels // Combustion and Flame. -1976.-Vol. 26. -P. 201-217. DOI: 10.1016/0010-2180(76)90072-9.

9. Polandov Yu. Kh., Barg M. A., Vlasenko C. F. Modeling a combustion propagation in air-gas mixtures using the large-particle method // 6th GRACM International Congress on Computational Mechanics. Greece, Aristotle University of Thessaloniki, 19-21 June 2008 : Book of Abstracts.-Sofia Publications, 2008.-P. 79.

10. Davydov Yu. M. Large-particle method // Encyclopaedia of Mathematics. Vol. 5.-London : Kluver Academic Publishers, 1990. URL: http://www.encyclopediaofmath.org/index.php?title=Large-particle/method&oldid=14385 (дата обращения: 25.06.2016).

11. Годунов С. К. Разностный метод численного расчета разрывных решений уравнений гидродинамики // Математический сборник. -1959.-Т. 47, № 8-9. -С. 271-306.

12. Раушенбах Б. В. Вибрационное горение. -М. : Физматгиз, 1961. -500 с.

13. Higgins В. On the sound produced by a current of hydrogen gas passing through a tube // Journal of Natural Philosophy, Chemistry and the Arts. -1802. -Vol. 1. -Р. 129.

14. Rijke P. L. Notiz ьber eine neue Art, die in einer an beiden Enden offenen Rцhre enthaltene Luft in Schwingungen zu versetzen // Annalen der Physik und Chemie. - 1859. - Vol. 183, Issue 6. - P. 339-343. DOI: 10.1002/andp.18591830616.

15. Hermann von Helmholtz.On the sensations of tone as a physiological basis for the theory of music. Alexander John Ellis. -Longmans, Green, 1885. -576 p.