The subject of the invention is a process device for coating particles that falls within the field of chemical and pharmaceutical technology. It represents an improvement on the process equipment for coating particles by bottom spraying and works on the principle of solid particles fluidization. The improvement was achieved with the new swirl flow generator design. Besides, the improvement of the conventional Wurster coater was attained by installing slots for additional air inflow in the chamber. Compared to the conventional Wurster coater, both construction improvements enable better coating film uniformity and coating process robustness.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 12184091The paper presents experimental work in a Wurster type coater. The pressure drop in the draft tube during the coating process was measured. The purpose of this study was to investigate the potential use of pressure drop fluctuation analysis to estimate quality parameters such as coating thickness uniformity, coating yield and degree of agglomeration. Combining different Wurster chamber geometries, intake airflow rates and draft tube heights, 20 coating experiments were performed. Based on Fast Fourier Transform analysis of raw pressure drop signals, four flow regimes were identified. The characteristic frequency bands were: 2-5 Hz (regime A), 13-16 Hz (regime B), periodicity of low frequencies (regime C) and exhibiting of two characteristic bands, 2-5 Hz and 13-16 Hz (regime D). In a particular coating experiment, the relative standard deviation (RSD) of the pressure drop signal and the identified flow regime provided sufficient information for a reliable estimate of coating quality parameters. Pressure drop fluctuations did not change significantly during the coating process, which provides an acceptable assessment of the aforementioned parameters even at the beginning of coating.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 3453553This paper deals with the application of Computational Fluid Dynamics simulation in the development of a new generation cooking appliance in Gorenje concern. As the oven is multifunctional, radiation, conduction, natural and forced convection mechanisms of heat transfer are used. The Discrete Ordinate (DO) model is used for radiation. The density of air is described by incompressible ideal gas equation in a natural convection model. The intention was to create the best possible baking conditions for different heating systems. Several discrete models were created. The influence of geometry change and boundary conditions variations to the velocity and temperature field distribution in the oven cavity was analyzed. The results of numerical simulations are validated with measurements taken from an oven prototype. The agreement was good. After successfully passing the standard tests, the oven came into serial production and was launched on the market.
F.06 Development of a new product
COBISS.SI-ID: 12216347Obstructive sleep apnea/hypopnea syndrome (OSAS) is sleep-related breathing disorder developed as a consequence of the upper airway anatomical characteristics and neuromuscular activity. To clarify upper aiway collapsing mechanism and snoring, as one of the OSAS symptomes, FSI analysis is used. We focus on the velopharynx region where the upper airway collapsibility is largest. At the inspiration phase we find out that additional airway narrowing occurs because of the high negative pressure. Also, vibrations of soft tissue appear as a consequence of the flow characteristics. These vibrations may be the main attribute of snoring.
E.01 National awards
COBISS.SI-ID: 13013787This paper deals with critical flow regimes that may induce unacceptable water hammer in Kaplan turbine hydropower plants. Water hammer analysis should be performed for normal, emergency and catastrophic operating conditions. Hydropower plants with Kaplan turbines are usually comprised of relatively short inlet and outlet conduits. The rigid water hammer theory can be used for this case. For hydropower plants with long penstocks the elastic water hammer should be used. Some Kaplan turbine units are installed in systems with long open channels. In this case, water level oscillations in the channels should be carefully investigated. Computational results are compared with results of measurements in recently rehabilitated seven Drava river hydroelectric power plants in Slovenia. Water hammer in the six power plants is controlled by appropriate adjustment of the wicket gates and runner blades closing/opening manoeuvres. Due to very long inflow and outflow open channels in Zlatoličje HPP a special vaned pressure regulating device attenuates extreme pressures in Kaplan turbine flow-passage system and controls unsteady flow in both open channels. Comparisons of results include normal operating regimes. The agreement between computed and measured results is reasonable.
F.17 Transfer of existing technologies, know-how, methods and procedures into practice
COBISS.SI-ID: 12486939