Evaluation of the Suppression Conditions for Combustion and Detonation Waves
- PDF / 161,780 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 63 Downloads / 175 Views
aluation of the Suppression Conditions for Combustion and Detonation Waves A. A. Vasil’eva,b
UDC 534.222.2+536.46+661.215.1
Published in Fizika Goreniya i Vzryva, Vol. 56, No. 5, pp. 39–44, September–October, 2020. Original article submitted October 14, 2019; accepted for publication November 6, 2019.
Abstract: Formulas based on conservation laws are proposed for evaluating the conditions for combustion and detonation waves using dust or water clouds. The formulas allow the determination of the minimum concentration of dust or atomized water droplets in a cloud and the minimum length of the cloud. Specific data on the conditions for quenching methane–air mixtures typical of coal mines are given. These data indicate that the dust concentrations and cloud sizes recommended by the Russian Federation standards allow, at best, the suppression of only low-velocity combustion waves. Keywords: combustion, detonation, suppression. DOI: 10.1134/S0010508220050032
INTRODUCTION The problem of explosion of methane mixtures when using light sources in mines had arisen since the ancient times when coal had begun to be mined. Unfortunately, the problem of preventing mine explosions still remains relevant and very important because accidental explosions lead to human losses and damage to the mining equipment and the mine itself. If an explosion did occur, is it possible to stop the propagation of the resulting blast wave? There are many methods of blast-wave mitigation, such as the injection of inert gases (beyond the concentration limits), the injection of inhibitors (chemical action, see, e.g., the works of Azatyan [1]), the creation of dust or water clouds on the wave path, etc. Hundreds of papers have been published reporting attempts to simulate mine explosions using models of heterogeneous media. Unfortunately, available numerical calculations describe the dynamics of flame acceleration and blast-wave attenuation upon interaction with dust clouds only at a qualitative level. Calculation rea
Lavrentyev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia; [email protected]. b Novosibirsk State University, Novosibirsk, 630090 Russia.
sults differ markedly from the dynamic parameters of real blast waves (e.g., in the dust concentration required for suppression and the length of the dust cloud along the mine tunnel). In contrast to previous papers where an attempt was made to evaluate the partial mitigation of blast waves, this paper focuses on the criteria of their complete suppression and presents simple estimates for methane–air mixtures as an example.
SUPPRESSION OF COMBUSTION WAVES BY A DUST CLOUD It is known that the limiting propagation modes are low-velocity (cm/s) laminar burning and supersonic (km/s) detonation. We consider separately the results of suppression of these waves upon interaction with dust and water clouds. Since the minimum ignition energy of methane–air mixtures is of the order of 0.3 mJ [2] (Fig. 1) and the critical energy of detonation initiation is abo
Data Loading...
