We have developed a two-phase boundary layer model for convective flow boiling, based on the analogy of surface roughness. The model includes the impact of bubble nucleation and their size on the development of the liquid velocity profile in the bubble boundary layer. In this way, the wall friction in the boundary layer increases and affects also the heat transfer at boiling. This is reflected in the wall-to-fluid heat transfer model. Using this novel approach, we have successfully simulated the profiles of phase velocities, temperature and void fraction in various experiments.
COBISS.SI-ID: 23957031
In cooperation with european partners, we have performed a comprehensive validation of the ASTEC code for the simulation of thermal-hydraulic phenomena and aerosol behaviour in the nuclear plant containment by simulating the following experiments: — Phebus FPT2, performed in the Phebus facility at the Cadarache research centre (France), — KAEVER, performed in the facility of the same name at Battelle Ingenieurtechnik (Germany), — PACOX Px1.2, performed in the facility Battelle Model Containment (Germany), — LACE LA4, performed in the LACE facility at Westinghouse Hanford Company (USA).
COBISS.SI-ID: 23560999
Steam explosion experiments revealed that melt material properties significantly influence fuel-coolant interaction. The reason could be the different melt droplets freezing due to different melt material properties. A melt droplets solidification model, by which the growth of the solid crust on the droplets surface during the premixing phase may be simulated, was developed with corresponding melt drop break-up criteria. We also developed an explosion model, by which the influence of the formed crust on the fine fragmentation process during the explosion phase may be considered.
COBISS.SI-ID: 23573287
A multiscale model that describes the behaviour of a polycrystalline material, composed of randomly sized, shaped and oriented grains, was used for a wide study of microstructurally short cracks. The observed configurations included straight cracks contained within grains and cracks, kinked on the boundary between two grains. A large number of simulations was followed by statistical analysis. The calculated results are the first of their kind in the literature and represent and important scientific contribution to the understanding of the growth rates of short cracks.
COBISS.SI-ID: 24131367
A novel method for optimization of the maintenance activities of the generating units in the power system is presented. The loss of load probability of the power system is selected as a measure, used for the assessment of the power system reliability. The determination of the optimal maintenance schedule is done with the application of genetic algorithm. The obtained results show the major improvement and advantages of the new method compared to the previous approaches.
COBISS.SI-ID: 23799847