Obliczenia numeryczne spalania paliw gazowych

Modelowanie numeryczne procesów spalania jest wymagającym zagadnieniem naukowym oraz inżynierskim ze względu na złożoność procesu. Jednakże konieczność ciągłego rozwoju energetyki w kierunku nisko emisyjnych technologii spalania powoduje, że modelowaniu tych procesów poświęca się coraz więcej uwagi. Wynika to m.in. z faktu, że zastosowanie metod numerycznych pozwala na uzyskanie znacznych oszczędności przy projektowaniu instalacji spalania paliw przez wyeliminowanie konieczności budowy kosztownych prototypów. Modelowanie numeryczne umożliwia także na wcześniejsze dokładne określenie zachowania układu przy zmianie paliwa. W artykule zaprezentowano zastosowanie modelu spalania dyfuzyjnego oraz najważniejsze równania, które go opisują. W drugiej części artykułu przedstawiono własne wyniki prac, w których wykorzystano komercyjny kod numeryczny Ansys Fluent 16.0 do modelowania procesu spalania mieszaniny gazu w hipotetycznej komorze spalania

Numerical analysis of heat exchanger with emergency leak

Heat exchangers belong to the group of devices, whose proper operation is essential for the proper conduct of industrial processes. The growing influence of numerical methods in the design stage of exchanger, allows to optimize their design in terms of efficiency and meet the specified thermal parameters. A relatively new way to use numerical simulation is the study of unsteady heat transfer that characterized their work during failure. The article presents results of numerical analysis of the operation of a hypothetical heat exchanger with emergency leak of one of the coils. The effects of stream loss in the pipe and change of flow dynamics of entire system were taken into consideration. The importance of location of leak on the behavior of heat exchanger was also taken into account. The simulation was performed using the commercial software Autodesk Simulation CFD

Selected issues of coal-fired power generation in terms of maintaining its high share in the future structure of electricity generation in Poland

The Polish economy is one of the most dynamically developing economies in Europe. However, this development over the next 30 years is threatened by the lack of adequate supply of cheap and reliable energy. This is due to an array of negligence and delays in the expansion and reconstruction of the energy system. Due to the increasingly urgent need to solve this problem, many concepts about the direction in which the development of the Polish power system should go have emerged. This article presents arguments emphasising the advisability of maintaining the maximum high share of coal-fired power plants in the future structure of power generation. There is proven that raw materials in Poland may ensure stable development of the economy for next 100 years. Also, thanks to new technologies, CO2emissions may by reduced by half

Application of biomass swirl burners in high-power boilers

Solid biomass (both forest and agricultural) is recognized as a valuable source of chemical energy, that can be transformed into electricity or heat. Biofuels are very popular in small scale energy systems, but they can also be utilized in medium and high capacity municipal and industrial power units. Therefore, dynamic development of various machines and devices, designed for efficient biomass energy conversion, is observed. One of the possible application of solid biofuels in power industry, dedicated in particular to water-tube boilers, uses individual swirl burners fed by the biomass dust. They can be used as peak load or quick stop/start devices in stoker furnaces and primary burner in flue and smoke-tube boilers as well. In this article the implementation of swirl biomass burners in high capacity power boilers was presented and described. Both technical problems, closely related with biomass co-firing in coal-fired power plants, and design methodology of mentioned burners were discussed. Finally, the 3D visualization of proprietary solution of swirl burner and its description were provided

Dual ORC-Brayton power system for waste heat recovery in heavy-duty vehicles

Reducing the amount of energy required in industrial activities is one of the proven ways to achieve major cost savings, especially in the face of soaring energy prices. In the transport sector, besides the financial benefits, low energy consumption leads to the significant reduction of emissions of many pollutants. In this paper the new concept of dual power technology, dedicated to heavy road transport, was modelled and analysed by computer simulations. The combination of organic Rankine cycle and Brayton cycle was proposed, where the waste heat of fumes was recognized as a upper heat source, whereas the surrounding was adopted to be the lower one. Improvement of total energy conversion efficiency of the truck was the key success factor. Environmental friendly fluids (air and R123) were utilised. The operating parameters, power characteristics and energy streams (i.e. dispersion) of the system were evaluated, calculated and commented from the perspective of its theoretical profitability. The calculated net power capacity of analysed dual system was around 50 hp for 100% load. However, when the engine load is below 50% of nominal capacity, the power generation of combined system might be lower than in the case of single ORC system

Dual ORC-Brayton power system for waste heat recovery in heavy-duty vehicles

Reducing the amount of energy required in industrial activities is one of the proven ways to achieve major cost savings, especially in the face of soaring energy prices. In the transport sector, besides the financial benefits, low energy consumption leads to the significant reduction of emissions of many pollutants. In this paper the new concept of dual power technology, dedicated to heavy road transport, was modelled and analysed by computer simulations. The combination of organic Rankine cycle and Brayton cycle was proposed, where the waste heat of fumes was recognized as a upper heat source, whereas the surrounding was adopted to be the lower one. Improvement of total energy conversion efficiency of the truck was the key success factor. Environmental friendly fluids (air and R123) were utilised. The operating parameters, power characteristics and energy streams (i.e. dispersion) of the system were evaluated, calculated and commented from the perspective of its theoretical profitability. The calculated net power capacity of analysed dual system was around 50 hp for 100% load. However, when the engine load is below 50% of nominal capacity, the power generation of combined system might be lower than in the case of single ORC system