Browsing by Author "Zlateva P."

Now showing 1 - 3 of 3
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    Cost analysis at different energy sources for heating of an air-supported dome for indoor tennis
    (2021-07-12) Gavrilov V.; Penkova N.; Zlateva P.; Mladenov B.
    Numerical analyses of the energy supply for heating of air supported structure for indoor tennis in Sofia via district heating, gas and liquid fuels are performed. The computational procedures are implemented through thermal balances of the structures, calibrated on the base of in situ measurements of the indoor temperature and the amount of the fuel, consumed at heating of an air supported balloon for tennis in University of Chemical technology and Metallurgy. The profitability of the different heating variants is estimated using the price of the energy and the systems.
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    IMPROVEMENT OF FIRING CURVE OF CERAMIC WARE VIA MODELLING AND NUMERICAL SIMULATION OF THE COUPLED THERMO-MECHANICAL PROCESSES IN THE MATERIAL
    (2021-01-01) Penkova N.; Krumov K.; Zlateva P.
    A mathematical model of coupled heat transfer and mechanical processes in ceramic ware at firing is developed. It is based on information about the thermo-mechanical behaviour of the material at sintering, obtained experimentally. The model is solved numerically for massive bodies of technical ceramics to estimate and prevent the reasons for cracks appearance at their firing in chamber kilns. The transient thermo-mechanical processes in the fired mass are simulated varying with the heating rate of the firing curves. The investigated thermal regimes are analysed on the base of the results about the temperature and stresses fields in the articles. Approaches for improvements of the fired curve are discussed in order to prevent defects of the products.
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    Influence of the polyester non-wovens production type on their thermal and flammability properties
    (2022-12-01) Petkova-Slipets R.; Zlateva P.; Staneva D.
    In recent years, non-wovens have become the main segment of textile production because they can find applications in different areas. Thermal insulation properties, fire resistance, and flexibility make them cost-effective and efficient insulation panels for buildings. This paper aims to study the influence of the production method and surface treatment on the thermophysical characteristics and behavior under direct fire of two polyethylene terephthalate non-woven fabrics. The fibers have been bonded with polyacrylate adhesive or thermal and coated with silicone. Infrared spectroscopy, optical microscopy, and thermal analyses were applied to compare the non-wovens’ morphology, composition, and thermal properties. It founds that the non-woven polyester with acrylic additives and adhesive bonding has a higher thermal conductivity value and high flammability with complete combustion. In contrast, thermosetting siliconized polyester materials have limited flammability with limited droplet release. The silicone-based finish protects the polyester fibers leading to self-extinguishing and stopping the complete combustion of the sample.