Maciej Zawiślak

Analysis of screw propeller 4119 using the Fluent system

The aim of this paper was to carry out an analysis of screw propeller 4119 using the RANS method. A computer program for creating spatial propeller geometry was developed for this purpose. Two-equation turbulence models: k-ɛ and k-ω were adopted for calculations. The calculations were performed for an isolated propeller. The results were used to determine the propellers hydrodynamic characteristics. The calculation results were compared with experimental results.

Analysis of hull resistance of pushed barges in shallow water

Analysis of hull resistance of pushed barges in shallow water These authors performed a set of numerical calculations of water flow around pushed barges differing to each other by bow forms. The calculations were executed by means of FLUENT computer software. Turbulent free-surface flow of viscous liquid was considered. In this paper the calculated values of barge hull resistance split into bow, cylindrical and stern part components, have been compared and presented.

Hull Resistance of An Inland Waterway Vessel in Model Scale and in Full Scale

Abstract Data from model tests of an inland waterway vessel in shallow water have been used by the authors to prepare the resistance prediction in full scale. The common ITTC-1978 extrapolation procedure was applied using form factor determined according to the Prohaska method and, separately, by fitting the approximation function to resistance data. At the same time a series of CFD computations of ship flow has been carried out in model scale and in full scale, with double-body model as well as including the effect of free surface. The results of computations were used to determine total resistance and form factor. The values of form factor determined using different methods are similar and relatively high in comparison to values being applied to conventional sea going ships. Resistance prediction according to the ITTC-1978 with form factor was compared to prediction without form factor. The relative difference of resistance amounts 28% at ship speed of 10 km/h and 24% at ship speed of 12 km/h.

An innovative method for exhaust gases toxicity evaluation in the miniature turbojet engine

Purpose The purpose of this paper is to present an assessment method of the toxicity emission evaluation during combustion in the miniature turbojet engine. Design/methodology/approach A small-scale turbojet engine was used for the research because measurements on real aircraft turbines are complex and expensive. The experiment was performed in accordance with innovative BAT – CELL Bio – Ambient Cell method which consists of determination of virtual toxic impact of the gas mixture on the living cells; it is therefore a direct method. The most significant innovation of this method is that, during the test, which consists of exposing the cells to the gas mixture, the cells are deprived of culture fluid. Findings The preliminary analysis shows that the method used here allows to determine the virtual impact of the gases on the human respiratory system and skin. It could be useful in defining the arduousness of an airport. The obtained results show that both of exhaust gases represent similar toxicity. Practical implications The new in vitro method allows to determine the virtual impact of the gases on the human respiratory system and skin. Significant potential for further research not only on the miniaturised engines, but also in the case of real objects, as this method does not have to be performed in a laboratory. Originality/value The work presents potential application of the innovatory method for exhaust gases toxicity evaluation in jet engines, which could be useful in defining the arduousness of an airport.

Analysis of Blood Flow Through the Pathologically Changed Main Artery

During the examination a Computational Fluid Dynamics (CFD) analysis of blood flow through the physiological and pathologically changed aorta was performed. The model used in the Fluid—Structure Interaction analysis (FSI) has been enriched by a variable thickness of the wall in the section being subject to lesions. The influence of the occurrence of pathological change in the descending section of the thoracic aorta on the nature of blood flow, the value of flow parameters of fluid and endurance parameters of the wall of an arterial vessel, was demonstrated.

Analysis of the Blood Flow Through the Centrifugal Pump

Blood flow simulation was conducted for the peripheral centrifugal pump of the artificial heart by use of numerical methods. Flow parameters were examined for the destruction of blood morphological elements, the results were compared with literature data. The learned lessons led to changes of the pump geometry, then further simulations for different constructional variants were carried out. The results of calculations led to choosing the best structural solution for heart pump and follow-on conclusions on what kind of changes may improve the flow parameters and reduce the risk of destruction of blood elements.

Entrance research on pressure distribution in combustion chamber of gasoline engine applied in electric generator, fuelled by syngas, for different ignition timing

Synthetic gas (syngas) produced form waste organic matter may be used as a fuel for internal combustion engines. Possibilities of syngas application as an independent IC engine energy carrier are limited. Designed system of energy conversion from waste to electricity is expected to produce gas consists mainly carbon monoxide, methane, hydrogen and carbon dioxide. Based on theoretical study and own research, as the main factors which impact on floating syngas composition the quality of input substance, process temperature and gasifying medium application were identified. The fluctuation of syngas composition contributes important challenge in aspect of energetic efficiency and mechanical durability of generator system. The researches were provided on research test bed, which enables pressure distribution measurement in the combustion chamber (for various mixture of synthetic gases) and correction of ignition timing. The results of the researches indicate that proper correction of the ignition advance allows syngas mixtures combustion in wide range of their composition.

NUMERICAL ANALYSIS OF VOLATILE ORGANIC COMPOUNDS CONCENTRATION IN A E SEGMENT VEHICLE INTERIOR

Constantly increasing amount of cars causes significant deterioration of air quality. Emission of harmful substances such as aromatic hydrocarbons or soot has negative influence for human health, especially for the respiratory system. Pollutants from engine vehicles are emitted at the people living height and, especially in cities, could cumulated because of weak ventilation among the street canyons made by buildings and infrastructure. Dynamic development of motorization and people lifestyle make the time spent inside the car is getting longer. Fumes and other air pollutants can get into the car cabin, what is extremely dangerous for driver and passengers. The pollutants inside the vehicle can also accumulate and if cabin is not well ventilated, the concentrations of them could be really high. It cause changing the microclimate inside the car cabin and has negative influence on the people staying inside the car, such as lowering of comfort and focus of driver and health effects. Previous studies have shown that the highest concentration of most of the pollutants in the vehicle cabin is located at the height of the drivers head. Of course, it depends on many factors like type (category) of vehicle or geometry of nozzles in the ventilation system. The study aim was to define concentration of volatile organic compounds in an E segment vehicle cabin by using computational fluid dynamic simulation.