Marcin Sosnowski

Modeling of Thermal Cycle CI Engine with Multi-Stage Fuel Injection

This work presents a complete thermal cycle modeling of a four-stroke diesel engine with a three-dimensional simulation program CFD AVL Fire. The object of the simulation was the S320 Andoria engine. The purpose of the study was to determine the effect of fuel dose distribution on selected parameters of the combustion process. As a result of the modeling, time spatial pressure distributions, rate of pressure increase, heat release rate and NO and soot emission were obtained for 3 injection strategies: no division, one pilot dose and one main dose and two pilot doses and one main dose. It has been found that the use of pilot doses on the one hand reduces engine hardness and lowers NO emissions and on the other hand, increases soot emissions.

EXPERIMENTAL STUDY OF THERMAL EFFECTS IN COOLING OF CIRCULAR CYLINDER IN LOCK-ON CONDITIONS

The paper presents a simple method for determining the phenomenon of unsteady thermal effects in cooling a circular cylinder. The research has been undertaken in order to explain the thermoaerodynamic processes, which are characterized by the turbulent structure of the flow around a stationary rigid heated cylinder cooled by the oscillating flow. The forced convection of heat occurs in the presence of not only random velocity fluctuation but also in the conditions of periodical forms of motion caused mainly by the process of vortex going down and externally formed oscillations of the inflow. The Nusselt number was evaluated at various frequencies of disturbances of the inlet velocity field, especially in lock-on conditions, on the surface of the circular cylinder versus angular location Θ = 0-180°. The subject of the study focuses on the analysis of current state of the problem and development of the method to measure and calculate basic values that characterize unsteady processes of thermal effects on the circular cylinder surface and indication of the directions of further work.

Effect of PVP and Polybond Compatibilizers on Dynamic Properties of Polymer Blends Analyzed with DMTA

The properties of the polymer blends depend significantly on the type of the components. That kind of influence is manifested especially in the change of physical properties. The crucial condition for reaching the homogeneity and the properties of a polymer material is its mutual miscibility. Additional agents that make mixing easier are usually applied. They have reactive effect which results in a chemical modification of output polymer along with the change in its chemical structure and the structure of macrochains. In order to achieve this within the confines of the carried research, the polyvinylpyrrolidone (PVP) and polybond has been used. Some results concerning mechanical properties of polypropylene (PP) and polyamide (PA) blends with the addition of PVP and polybond are presented in the paper. In case of mixing PP with PVP, the hydrophobic interactions occur in the created macromolecules with the participation of the hydrocarbon chains. In case of mixing PA with PVP, the PVP solution in PA is created, with strong intermolecular interactions, including the hydrogen ones. The intermolecular interactions occur and they differently influence parameters of the modified materials in the blends on the basis of such polymers. Therefore the aim of the research was to evaluate the influence of the compatibilizers such as PVP and Polybond 3150 on the dynamic properties of PP/PA blends. The analysis of dynamic proprieties of polymer blends was performed with the Dynamic Mechanical Thermal Analysis (DMTA). The mixing of polymers in different proportions with compatibilizers (PVP, Polybond 3150) results in materials of completely different properties in comparison to the base materials. Detailed results concerning response to sinusoidal load in function of temperature and frequency are presented in the paper.