Vpliv biogoriv na tokovne pojave v vbrizgalni šobi dizelskega motorja : doktorska disertacija

slovenian

doktorska dela

2013

Univerza v Mariboru, Fakulteta za strojništvo

Fuel spray investigations belong to the field of the two-phase flows witch presents the study of physical fuel property dependent spray characteristics. The research will be focused on different type of fuels under different operating conditions. The investigation of spray development as contributing factor in mixture formation is also very important for the study of processes in internal combustion engine. Existing physical-mathematical model for two phase flows generally gives good results. Several empirical constants are present in sub models and they have significant influence on spray development. They are usually depended on injection system and the geometry ofinjection nozzle. The improvement of physical-mathematical model including the most influential factors with in the momentum equation for spray development, will enable efficient analysis of spray characteristics of alternative fuels. The model will also include the equations for bubble density and the equation for cavitation occurrence. The parts of equation representing the spray development, formation of bubbles and cavitation will be modelled with the adaptation of knowledge of other authors, where the modified model will be able to predict the spray development more accurately. The work contains both experimental and numerical part. Physical properties ofthe fuels, characteristics of the fuel injection process and high-speed recordings are described and analysed in the experimental part. The simplifiedphysical-mathematical models is presented in the numerical part. Thedissertation shows, that the improvement of standard mathematical model forspray development considering the physical fuel properties, the operating conditions and the injection characteristics enables determination of empirical constants. Additionally the physical-mathematical model can be included. By using of appropriate expressions, the empirical parameters valuescan be determined and enable predictions of potential problems which could appear in diesel engines during operation with biofuels.

08.08.2023