In this paper, we report on the development of a numerical method aimed at simulation of turbulent heat transfer and turbulent flow of fluids. The developed algorithm is based on a hybrid LES/URANS approach and on the boundary element method. Validity and accuracy of the method is presented on a differentially heated enclosure test case.
COBISS.SI-ID: 18814742
Currently, conventional energy sources i.e. fossil fuels represent the main segment as regards electricity generation. Thus, their contribution to global CO2 emissions is considerable. This study considers carbon capture and storage (CCS) as a promising solution for the environmental problems we are now facing. Based on previous research, post-combustion capture (PCC) has been recognized as being the more appropriate technology for CO2 capturing from the existing power plants. The main purpose of our study was to investigate the correlation between the efficiency of carbon dioxide capturing and its influence on the reduction of electricity production efficiency and levelized cost of electricity at the new unit VI of the thermal power plant of TE Šoštanj, Slovenia. A zero-dimensional model was used for appropriately considering the flows of mass and energy within the PCC system as a function of carbon dioxide capture efficiency and a rather simple cost model was applied for predicting the additional levelized electricity cost due to PCC system implementation. By changing the efficiency of the capture system, as well as the evaluated prices of carbon emission coupons, our results show the possible economic eligibilities of the PCC system in the future.
COBISS.SI-ID: 18630678
In this paper, the possibility of replacing mineral diesel fuels with different biofuels is analyzed. The study focuses on a numerical investigation of biofuels' influence on an injected fuel-spray cone's angle and length, which have further influence on the combustion process and the formation of pollutants in internal combustion engines. The influence of different physical and chemical properties of pure mineral diesel fuel, biodiesel fuel and their blends on spray characteristics was investigated with the AVL FIRE simulation program. Several different empirical model parameters, usually the engine-operating regime and biofuel used, must be defined when using numerical models. In this study, the numerical model implemented in AVL FIRE was modified so that all model parameters were determined regarding biofuel properties and engine-operating conditions. Experimental measurements of spray development in a cylindrical chamber pressurized with nitrogen at 40-60 bar were performed for validation of the modified numerical model. Photos of spray development were taken with a high speed camera simultaneously with pressure and needle-lift signals. The comparison of experimental and numerical results confirmed the usability of the numerical model. Numerical results of spray development for different biofuels under different operating regimes and ambient pressure confirm the possible usage of biofuels as a replacement for mineral diesel fuel in diesel engines with the early generation of fuel injection systems.
COBISS.SI-ID: 18359830
In this paper a benchmark solution for the conjugate heat transfer of backward-facing step flow is computed using the stream function vorticity formulation. The numerical solution is obtained using the multidomain Boundary Element Method. A significant difference was found when comparing the results with the prior benchmark solution computed by Kanna and Das (2006). Similar disagreement has also been reported in the work done by Teruel and Fogliato (2013). The new benchmark temperature and Nusselt number values were obtained using Richardson extrapolation to zero-sized mesh. The presented results have excellent agreement when compared to the third numerical code.
COBISS.SI-ID: 18416918
In this lecture, we report on the development of a numerical method aimed at simulation of heat transfer and flow of nanofluids. The developed algorithm is based on the boundary element method. Validity and accuracy of the method is presented on a flow around a cylinder and a elliptical cylinder.
COBISS.SI-ID: 18768150