Miroslav Mynarz

Experimental Determination Of DeflagrationExplosion Characteristics Of Methane–airMixture And Their Verification By AdvancedNumerical Simulation

Venting is a widely applied method to protect buildings and technological equipment from effects of internal explosion. The key problem in venting is the adequate design of vent area and an effective material of venting element. Α set of 76 experiments on partly confined methane–air mixture explosions with various parameters was processed. In terms of experiments, vent areas and venting elements with variable values of static activation pressure were changed. During measurements, certain items were determined at steady stoichiometric mixture concentration and atmospheric conditions: reduced explosion pressures, rates of reduced explosion pressures rise, temperatures, flame lengths and deformations of experimental equipment enclosure. Together with experiments, modelling of these processes was carried out by the codes based on computer fluid dynamic (CFD) using numerical tool FLACS (Flame Acceleration Simulator). Results of experiments and CFD models are analysed and compared to each other.

Determination Of The Minimum Ignition Energy On Different Devices

Abstract This article focuses on determination of the minimum ignition energy of dust. For the measurement of the minimum ignition energy of dust are available device from different manufacturers. In this article, the comparison device from three manufacturers - Chilworth, Kühner and Anko are executed. For the experimental measurement of the minimum minimum ignition energy was chosen 5 dust samples so that they are represented sample of organic dust, synthetic organic dust and coal dust. The article briefly introduces each apparatus for determining the minimum ignition energy and there is a comparison of the results obtained with individual devices. Finally, it is an assessment the results obtained and used test equipment.

Study of the Effects of Transient Load on Envelope Structure

The contribution compares the response of envelope of chosen structure to the effects of transient load. The load was caused by air blast wave due to deflagration of methane-air mixture. The paper deals with interaction of incident blast wave and envelope structure. Considering blast courses obtained from experiments, two simplified models of load were developed. Load, defined by both load functions, was applied to 3D numerical model of the structure. Calculated result values of deflections of wall elements were compared to experimentally obtained deflections.

Non-linear approaches to the response of brick masonry wall to lateral loading

The response of brick masonry wall subjected to lateral loading is presented in this paper. Modelling and analysis of masonry seems to be complicated due to two-component material with different properties and dimensions. Out-of-plane loading adds another issue to be solved. Therefore, it is necessary to perform a calibration to evaluate the dynamic properties of the structure. The response of the finite element model is improved by predicting the parameter by performing a non-linear structural analysis. The deformations obtained numerically were compared to that of experimental observations. The experiments were carried out in one of the experimental galleries in the limestone pit. The study deals with the response of the masonry separating walls at various thicknesses, mechanical properties or loading. This contribution compares the effect of variability of particular parameters to the response of the walls. The results could be used for explosion prevention and protection; masonry buildings are taking into account considering the danger of explosion of natural gas or other items. For favourable design or assessment of masonry wall exposed to the out-of-plane load, which involves also explosion, it is possible to calculate the structure using some finite element model.

Effect of Size of Ignition Energy on the Explosion Behaviour of Selected Flammable Gas Mixtures

The determination of explosion indices of flammable gases is an important part of explosion prevention. Explosion indices could be influenced by initial temperature, initial pressure, humidity, ignition energy and others. This contribution deals with the effect of ignition energy size on explosion indices of flammable gases. For experimental measurements, three flammable gases were chosen—methane, propane and hydrogen. The chapter introduces the measurement results of the gas explosion parameters at various sizes of the ignition energy using explosion autoclave VA-20. Conclusions include the evaluation of influence of the ignition energy size on particular explosion indices.

Explosion limits of industrial spirit and their affecting by temperature

The article deals with the determination of industrial spirits explosion limits and their affecting by temperature. It describes the determination of explosion limits and the influence of temperature by correlation equations available in professional literature, as well as the validation of these data by means of experiments in explosion autoclave and explosion chamber.

Study of Distribution and Quantification of Flammable Gas in Confined Space

The contribution deals with leakage of natural gas from domestic low-pressure piping. Spreading of the leaked natural gas in the confined space is deals with and the areas are defined where local hazardous concentrations are formed. Mathematical CFD models provide broad overview of spreading of natural gas, in dependence on the elapsed time from the start of leakage. The contribution should improve the understanding of spreading and distribution of mixture of gaseous fuels in confined spaces, and thus leads to significant reduction of the risk of occurrence of fire or explosion or to prevention of these hazards.

Effect of temperature on the concentration explosion limits of combustible liquids

The contribution is focused on the theoretical calculations of the influence of the temperature on the concentration explosive limits of flammable liquids using empirical formulas. The first part of the paper is concerned with the theoretical basis of computation according to empirical formulas. The other part deals with experimental verification of the theoretical assumption of the calculation of the influence of the temperature on the concentration explosive limits of flammable liquids.