Browse

This paper presents the design and numerical analysis of an experimental system intended to study the effects of water curtains on the propagation of hydrogen explosions. The developed virtual model reproduces a test stand consisting of three successive chambers separated by two water-filled barriers acting as water curtain obstacles. The atmosphere in the chambers is composed of an explosive hydrogen–air mixture with a hydrogen concentration of 25%. The explosion is initiated in the first chamber, and the propa...

The present paper presents the transfer to the virtual environment and CFD analysis of physical experiments on the explosions of air-hydrogen mixtures carried out on a transparent stand, in the shape of a rectangular spiral. The shape of the stand was designed with the intention of directing the explosion process of the fuel mixture on a rectangular-spiral trajectory, with angles of 90 degrees. The free volume inside the spiral was sectioned by four foiled shutters into four ignition/combustion chambers, the first...

The continued development of human society, from the technical and economic point of view, has led to the need for the increasingly widespread use in the various existing industrial branches of chemical substances and compounds in the form of combustible dust and dust. The processing, handling and storage of these pulverized substances often leads to the emergence of complex explosive mixtures whose explosiveness characteristics cannot be assimilated with the data available in the literature. In places where the p...

An attack with a "improvised" explosive device (IED) is when someone uses a bomb and/or destructive device to cause damage, render someone helpless, harass, or divert attention. Terrorists, criminals, vandals, suicide bombers, and rebels all utilize IEDs. IEDs can take many different shapes because they are improvised; they can be as simple as a pipe bomb or as complex as a sophisticated weapon that can inflict significant damage and casualties. IEDs can be transported or carried in a car; they can also be deliver...

In chemical processes, fire and explosion prevention is crucial, especially when flammable liquids or gases are present because they can create explosive atmospheres of gas or vapour in the air. These include oil-based products and organic solvents. It is essential to understand these compounds' characteristics as well as the size of an explosive atmosphere. Explosion hazards as well as the locations where explosive atmospheres are present can be identified and assessed. Safety data sheets also contains crucial in...

Explosions may have severe consequences on the integrity of structural or nonstructural elements of a building. Being considered events with a low probability of occurrence, they are not considered directly in the design, except in certain special situations (accidental design situations). In the case of deliberate attacks, placing explosive devices at short distances or even attached to building elements can cause major local failures. Local failure and potential loss of load carrying capacity are dependent on lo...

According to ANSYS - developer of the Multiphysics platform for computer simulations - the FSI (Fluid-Structure Interaction) model can be used in all cases where a fluid encounters a solid structure, for example, wind gusts rotating a turbine, air washing the surface of a moving car etc. This method finds applications especially in the aeronautical and automotive industries, but also in medical research, such computer simulations track the influences of blood pressure and blood flow velocity in the veins. This pap...

Underground mining remains one of the most dangerous occupations in the world, and coalmining is known for its high accident rates. In this paper we aim to present an overview of safety in the extractive industry and we will present statistics on known accidents. The repeated occurrence of explosions in underground mining raises questions about the measures taken to prevent their occurrence. Hazard identification and risk analysis are necessary to identify adverse events that may lead to a hazardous situation, to ...

Unlike friable rocks, salt behaves pseudoplastic when blasted, which leads to other premises of the blasting technique compared to those applied for stratified sedimentary or eruptive rocks. Here can also add the salt inhibitory character on the thermodynamic parameters of the explosions, with effects on their efficiencies as well as some particularities of the execution of the blasting works due to the presence of methane gas in the salt mines. The article presents the results of the research carried out in fired...

Substances of petroleum origin that reach groundwater limit water use and can have irreversible effects on ecosystems interacting with them. Quantitative changes in groundwater and synergistic effects generated by petroleum products on ecosystems can be objectively quantified based on a scenario for the transport of pollutants concentrations through the aquifer. In this sense, with the help of mathematical models, the research estimates the spatial and temporal dimension of a possible accidental pollution by petro...

The heat transfer from the source of initiation to the adjacent surfaces is a physical phenomenon worth considering in the process of analyzing the fire. This complex phenomenon describes how the transport, exchange, and redistribution of the thermal energy are carried out and is based on the theoretical knowledge that describes the initiation and fire evolution in time. Flames transfer heat from nearby surfaces through two physical processes, convection, and radiation. A third mode of heat transfer is conduction,...

Most of the time, in assessing a situation where a leakage of combustible gas is involved, the volume of the room where the release occurs and the volume of the released gas is taken into account, thus resulting in an average concentration of the fuel gas applied to the entire volume of the room. In some cases, when the source of combustible gas is close enough to the source of initiation, or when air currents converge at the location of the source of initiation carrying amounts of combustible gas, the explosive m...

Within petroleum refining facilities are manufactured, used and stored significant amounts of hazardous materials, including raw materials, intermediates and final products. Within refineries there may arise the fire hazard for processing installations of the intermediate products with high melting point. For many of these intermediate products there are not determined the flammability parameters, fact which could allow the development and application of some efficient measures for prevention or limitation of dang...