Mario Holik

Analysis of wind influence to static stability of the eave framework

Eave framework is analyzed in this paper from the standpoint of statics. Loads taken into account are self-weight, snow weight and wind influence. 3D model of eave framework is generated in the software PartSolution (Cadenas) with certain simplifications in geometry. Simplifications are taken into account in order to reduce costs of the numerical calculation, especially the FSI calculation. The resulting pressure distribution solution obtained from CFD calculation is set as the boundary conditions on the eave framework when performing structural analysis. Solutions for equivalent stress as well as deformation are presented and analyzed. Also, solutions for airflow prediction around the eave framework are presented in order to analyze if it is possible to perform some changes in the construction in terms of reducing the air resistance and thus reducing the wind load on the construction.

Exergy analysis of a Brayton cycle with variable physical properties and variable composition of working substance

The exergy analysis of a Brayton cycle is performed in the paper. The four input variables: the ratio of the compressor exit and inlet pressures, the ratio of inlet temperature of gases in turbine and inlet temperature of air in compressor and the isentropic efficiencies of the compressor and turbine are analysed. The temperature ratio is varied in a way that the compressor inlet temperature of air is maintained constant, while the turbine inlet temperature of flue gases is varied from 900 to 1200°C. In the combustion chamber methane is completely combusted with excess air ratio which is determined by the temperature of flue gases at the turbine inlet. The analysis further includes variability of the molar heat capacities of air and flue gases with temperature and variability of their heat capacity ratios. The exergy destruction in turbine, compressor and combustion chamber and also total exergy efficiency of the cycle are considered in the analysis.