Ing. Jan Marek

13.01.2014
If containment of a flammable liquid is lost and the consequent vapor-air mixture is ignited, estimation of radiation from thermal radiation generated depends upon number of factors. The point source model for the prediction of thermal radiation from liquid pool fires was adopted for the evaluation of the effect distances of Pool Fire we modified the simple point source model for calculation of the effect distances directly from the mass of flammable liquid in Pool Fire. The point source model considers the heat source (i.e. the flame) as a point that emits in all directions. The original model considers the heat received by the observer as a fraction of the heat of combustion multiplied by the burning rate. This heat decreases with the square of the distance from the source and with the transmissivity of the ambient air. In the presented model we implemented different possibilities of heat fraction calculation and we introduced the flame length in order to calculate the point source-target distance. Finally we do not consider the atmospheric stability as s constant but we introduced simple mathematical correlation and compare both the model with and without this parameter. The modified relationship was compared with experimental results and discussion of results is performed.
13.01.2014
The application for the theoretical calculations of Jet Fire based on Yellow book was developed on JAVA platform and tested in NetBeans IDE 7.4. Model calculates the size and shape of a jet for gaseous releases from pipelines, tanks and two-phase releases from tanks. Chamberlain empirical formulas for vertical and inclined burns in a horizontal wind are used to describe the geometry of the flame. The model returns the ground level distance for each of the heat radiation level of concern (tested for 5, 8, 10 kW/m2). The model was used to calculate the heat radiation as a function of distance for a) CnH2n+2 (alkanes, n = 1-4), b) CnH2n (alkenes, n = 2-4), c) CnH2n+1OH (alcohols, n = 1-4) and hydrogen. The main benefit of presented model is that it allows a quick and fast estimation of the heat radiation from Jet Fire and could be further developed according to actual needs. It allows understanding the basic connections and the key parameters of Jet Fire phenomena from both the mathematical and physical point of view that make it primarily suitable for academic purposes.
30.08.2013
To understand the accident and at the same time to create a proper emergency scenarios, it is necessary to know the physical nature of emergency events. The aim of this contribution is to describe the possibility of verifying the characteristics of the phenomenon of Fire Ball, as accidental phenomenon, which is often present in major accidents in the industry. At the beginning of the contribution are described the conditions that are necessary or sufficient for its creation. There is also described a simple model for calculating the basic parameters related to this phenomenon - size, diameter, duration, effects distance, etc. In the second part of the contribution three major fire ball accidents using the ARIA and e-MARS databases are described. In the third part of the article description is made of the currently used mathematical models of the phenomenon and a comparison is made of the mathematical model developed and used for this work with the results of experimental simulations, theoretical models and the data from the accident with the occurrence of this phenomenon.

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