Method of comprehensive assessment of efficiency of decrease of fire and explosion risk of coal suspended particles

Methods and results of experimental study of explosive and wetting characteristics of coal dust are presented. Modified evaluation method of explosive characteristics of coal dust allows estimating critical concentrations of suspended dust at variation of temperature of ionizing ignition source corresponding to beginning of flame propagation by means of approximation method. Method of measuring the contact angle of particles of coal powder is based on visualization of the drop placed on the pressed coal

Investigation of Igniting Ability of Heterogeneous Systems by Means of Electric Spark

The article presents a physical model for determining the boundary conditions of ignition of a heterogeneous system, taking into account the heating of the liquid phase and its evaporation. The temperature distribution in a heterogeneous system is described by the obtained analytical expression. An algorithm describing the evaporation rate of the liquid phase is also defined. An expression describing the induction period can be used to determine the critical duration of the discharge, the reduction of which will lead to the ignition of the vapor-gas phase

Development of a Calculation Methodology for the Ventilation on a Besis of a Mobile Unit

An algorithm for the analysis of safety and efficiency of the processes, which are located inside the mobile unit are developed. It follows from the calculations that the safe concentration of combustible material in the space of industrial premises is about 3.69%. Automation systems must be focused on this value. The time of occurrence of the maximum permissible concentration of pollutant was determined and amounted to 160 seconds. It is shown that the ventilation rate of 0.5 would be sufficient for functioning of the object

The Dependence between the Ignition Value of Air Suspension and the Size of the Reaction Chamber

The influence of the geometric factor of the reaction chamber on the limit value of the air suspension ignition is studied. It is found that in determining the lower concentration limit of the flame propagation (LCLFP), it is most promising to use an installation with a cylindrical reaction chamber whose height is equal to the diameter. The dependence of the determination of the LCLFP value on the geometric factor of the reaction chamber is proposed, tested on metal powders and organic dust-forming materials. The expression allowing to carry out the comparative analysis of scientific results received on other technical devices with the results received on the installations executed according to the requirements of normative and technical documentation is received that significantly reduces the volume of experimental works

The dependence between the ignition value of air suspension and the size of the reaction chamber

The influence of the geometric factor of the reaction chamber on the limit value of the air suspension ignition is studied. It is found that in determining the lower concentration limit of the flame propagation (LCLFP), it is most promising to use an installation with a cylindrical reaction chamber whose height is equal to the diameter. The dependence of the determination of the LCLFP value on the geometric factor of the reaction chamber is proposed, tested on metal powders and organic dust-forming materials. The expression allowing to carry out the comparative analysis of scientific results received on other technical devices with the results received on the installations executed according to the requirements of normative and technical documentation is received that significantly reduces the volume of experimental works

Method of comprehensive assessment of efficiency of decrease of fire and explosion risk of coal suspended particles

Methods and results of experimental study of explosive and wetting characteristics of coal dust are presented. Modified evaluation method of explosive characteristics of coal dust allows estimating critical concentrations of suspended dust at variation of temperature of ionizing ignition source corresponding to beginning of flame propagation by means of approximation method. Method of measuring the contact angle of particles of coal powder is based on visualization of the drop placed on the pressed coal