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EN
Liquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of the gamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble, and bubble one. In the research, a radiometric set consisting of two Am-241 sources and two NaI(TI) scintillation detectors have been applied. Based on the analysis of the signals from both scintillation detectors, the gas phase velocity was calculated using the cross-correlation method (CCM). The signal from one detector was used to determine the void fraction and to recognise the flow regime. In the latter case, a Multi-Layer Perceptron-type artificial neural network (ANN) was applied. To reduce the number of signal features, the principal component analysis (PCA) was used. The expanded uncertainties of gas velocity and void fraction obtained for the flow types studied in this paper did not exceed 4.3% and 7.4% respectively. All three types of analyzed flows were recognised with 100% accuracy. Results of the experiments confirm the usefulness of the gamma-ray absorption method in combination with radiometric signal analysis by CCM and ANN with PCA for comprehensive analysis of liquid-gas flow in the pipeline.
EN
The technology of solar-powered aerial vehicles requires enormous financial support and further development. For this purpose, the computational fluid dynamic can be used. In order to carry out necessary analyses and model development in this research, ANSYS Fluent software was used. Using the first version of the AGH Solar Plane model, preliminary analysis of lift, drag and tearing off the stream was performed. Four new geometries were prepared on which the flattening of upper surfaces for fixing solar panels was tested. The results were validated in the aerodynamic tunnel using particle image velocimetry method. Taking into account all analyses, a number of recommendations have been prepared that will be implemented to create an aircraft, which meets all target requirements.
EN
Hybrid Renewable Energy Systems connected to the traditional power suppliers are an interesting technological solution in the field of energy engineering and the integration of renewable systems with other energy systems can significantly increase in energy reliability. In this paper, an analysis and optimization of the hybrid energy system, which uses photovoltaic modules and wind turbines components connected to the grid, is presented. The system components are optimized using two objectives criteria: economic and environmental. The optimization has been performed based on the experimental data acquired for the whole year. Results showed the optimal configuration for the hybrid system based on economical objective, that presents the best compromise between the number of components and total efficiency. This achieved the lowest cost of energy but with relatively high CO2 emissions, while environmental objective results with lower CO2 emissions and higher cost of energy and presents the best compromise between the number of components and system net present cost. It has been shown that a hybrid system can be optimized in such a way that CO2 emission is maximally reduced and – separately – in terms of reducing the cost. However, the study shows that these two criteria cannot be optimized at the same time. Reducing the system cost increase CO2 emission and enhancing ecological effect makes the system cost larger. However, depends on strategies, a balance between different optimization criteria can be found. Regardless of the strategy used economic criteria – which also indirect takes environmental aspects as a cost of penalties – should be considered as a major criterion of optimization while the other objectives including environmental objectives are less important.
PL
Energia elektryczna produkowana z dostępnej powszechnie energii odnawialnej ze względu na nieprzewidywalność wytwarzania ma często bardzo niską jakość. Rozwiązaniem tego problem mogą być układy hybrydowe, w których systemy bazujące na energii odnawialnej połączone zostają z tradycyjnymi systemami bazującymi na energii nieodnawialnej. Integracja takich układów może znacząco zwiększyć ich niezawodność energetyczną i poprawić jakość dostaw energii. W niniejszym artykule przedstawiono analizę oraz optymalizację hybrydowego systemu energetycznego wykorzystującego moduły fotowoltaiczne oraz turbiny wiatrowe i podłączonego do sieci elektroenergetycznej. Komponenty systemu podlegają optymalizacji przy wykorzystaniu dwóch kryteriów optymalizacyjnych: ekonomicznego i środowiskowego. Optymalizacja została przeprowadzona w oparciu o wyniki pomiarów eksperymentalnych dla całego roku. Uzyskane wyniki pozwoliły na określenie optymalnej konfiguracji systemu hybrydowego, który stanowi najlepszy kompromis między liczbą komponentów a całkowitą jego wydajnością. Wykazano, że system hybrydowy można zoptymalizować w taki sposób, aby emisja CO2 była minimalna lub w taki sposób, aby całkowity koszty systemu NPC był minimalny. Przeprowadzone analizy pokazują jednak, że tych dwóch kryteriów nie można jednocześnie zoptymalizować. Zmniejszenie emisji CO2, a tym samym zwiększenie efektu ekologicznego sprawia, że system kosztuje znacznie więcej. Niezależnie od zastosowanej strategii kryterium ekonomiczne, które pośrednio uwzględnia aspekty środowiskowe (w postaci kar lub opłat środowiskowych), powinno być traktowane jako główne kryterium optymalizacji, natomiast inne kryteria, w tym środowiskowe, należy traktować jako drugorzędne.
EN
Consumption of energy is one of the important indicators in developing countries, but a lot of companies from the energy sector have to cope with three key challenges, namely how to reduce their impact on the environment, how to ensure the low cost of the energy production and how to improve the system overall performance? For Polish energy market, the number of challenges is greater. The growing demand for electricity and contemporary development of nuclear power technology allow today’s design, implement new solutions for high energy conversion system low unit cost for energy and fuel production. In the present paper, numerical analysis of modular high-temperature nuclear reactor coupled with the steam cycle for electricity production has been presented. The analysed system consists of three independent cycles. The first two are high-temperature nuclear reactor cycles which are equipped with two high-temperature nuclear reactors, heat exchangers, blowers, steam generators. The third cycle is a Rankine cycle which is equipped with up to four steam turbines, that operate in the heat recovery system. The analysis of such a system shows that is possible to achieve significantly greater efficiency than offered by traditional nuclear reactor technology.
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