1. The ǂeffect of fuel quality on cavitation phenomena in common-rail diesel injector—a numerical studyLuka Kevorkijan, Ignacijo Biluš, Eloisa Torres Jiménez, Luka Lešnik, 2024, original scientific article Abstract: Plastic is one of the most widely used materials worldwide. The problem with plastic
arises when it becomes waste, which needs to be treated. One option is to transform plastic waste
into synthetic fuels, which can be used as replacements or additives for conventional fossil fuels
and can contribute to more sustainable plastic waste treatment compared with landfilling and other
traditional waste management processes. Thermal and catalytic pyrolysis are common processes
in which synthetic fuels can be produced from plastic waste. The properties of pyrolytic oil are
similar to those of fossil fuels, but different additives and plastic stabilizers can affect the quality
of these synthetic fuels. The quality of fuels and the permissible particle sizes and number density
are regulated by fuel standards. Particle size in fuels is also regulated by fuel filters in vehicles,
which are usually designed to capture particles larger than 4 µm. Problems can arise with the
number density (quantity) of particles in synthetic fuels compared to that in fossil fuels. The present
work is a numerical study of how particle size and number density (quantity) influence cavitation
phenomena and cavitation erosion (abrasion) in common-rail diesel injectors. The results provide
more information on whether pyrolysis oil (synthetic fuel) from plastic waste can be used as a
substitute for fossil fuels and whether their use can contribute to more sustainable plastic waste
treatments. The results indicate that the particle size and number density slightly influence cavitation
phenomena in diesel injectors and significantly influence abrasion.
Keywords: plastic waste, synthetic fuels, pyrolytic oil, common rail, cavitation, erosion, particles
Published in DKUM: 05.07.2024; Views: 131; Downloads: 14
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2. Obtaining the synthetic fuels from waste plastic and their effect on cavitation formation in a common-rail diesel injectorLuka Kevorkijan, Amalia Palomar-Torres, Eloisa Torres Jiménez, Carmen Mata, Ignacijo Biluš, Luka Lešnik, 2023, original scientific article Abstract: The presented paper addresses two significant issues of the present time. In general, the studies of the effect of synthetic fuels on cavitation formation and cavitation erosion prediction in the nozzle tip of common-rail diesel injectors were addressed. The first problem is plastic waste, which can have a significant negative environmental impact if not treated properly. Most plastic waste has high energy value, so it represents valuable material that can be used in resource recovery to produce various materials. One possible product is synthetic fuel, which can be produced using thermal and catalytic pyrolysis processes. The first issue addressed in the presented paper is the determination of fuel properties since they highly influence the fuel injection process, spray development, combustion, etc. The second is the prediction of cavitation development and cavitation erosion in a common-rail diesel injector when using pyrolytic oils from waste plastic. At first, pyrolytic oils from waste high- and low-density polyethylene were obtained using thermal and catalytic pyrolysis processes. Then, the obtained oils were further characterised. Finally, the properties of the obtained oils were implemented in the ANSYS FLUENT computational program and used in the study of the cavitation phenomena inside an injection nozzle hole. The cavitating flow in FLUENT was calculated using the Mixture Model and Zwart-Gerber-Belamri cavitation model. For the modelling of turbulence, a realisable k–ε model with Enhanced Wall Treatment was used, and an erosion risk indicator was chosen to compare predicted locations of cavitation erosion. The results indicate that the properties of the obtained pyrolytic oils have slightly lower density, surface tension and kinematic viscosity compared to conventional diesel fuel, but these minor differences influence the cavitation phenomenon inside the injection hole. The occurrence of cavitation is advanced when pyrolytic oils are used, and the length of cavitation structures is greater. This further influences the shift of the area of cavitation erosion prediction closer to the nozzle exit and increases its magnitude up to 26% compared to diesel fuel. All these differences have the potential to further influence the spray break-up process, combustion process and emission formation inside the combustion chamber.
Keywords: plastic waste, synthetic fuels, pyrolytic oils, common-rail, cavitation, erosion, transient simulation
Published in DKUM: 18.03.2024; Views: 299; Downloads: 30
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3. Comparative study of various renewable fuels blends to run a diesel power plantEloisa Torres Jiménez, Marta Svoljšak, Andreja Gregorc, M. P. Dorado, Breda Kegl, 2010, published scientific conference contribution Abstract: In this paper bioethanol/diesel and bioethanol/biodiesel blends, at several concentrations and temperatures, are studied to find its possible commercial usage as a fuel to run a diesel power plant. The tested fuels were: net mineral diesel fuel (D100) , 5 % bioethanol/diesel fuel blend (v/v) (E5D95), 10 % bioethanol/diesel fuel blend (v/v) (E10D90), 15 % bioethanol/diesel fuel blend (v/v) (E15D85), neat biodiesel (B100), 5 % bioethanol/biodiesel blend (v/v) (E5B95), 10 % bioethanol/biodiesel blend (v/v) (E10B90), and 15 % bioethanol/biodiesel blend (v/v) (E15B85). The fuels were tested at: 30, 25, 8and -18 C. This paper shows the observations done in 8 samples during 5 weeks. After each week, each sample was overviewed, and changes related to stability, colour and aggregation were recorded. It has been proved that additives are not necessary to ensure stability of bioethanol/biodiesel blends under low temperature conditions, as the phase separation never happens.But in case of bioethanol/diesel blends some additives are necessary to keep stability under low temperature conditions. Based on this study, it can be concluded that blends of biodiesel fuel with bioethanol up to 15% can be used to fuel a diesel power plant if engine performance tests corroborate it. The same conclusion can be applied to blends of diesel fuel with bioethanol up to 15% blends if additives to keep stability are added.
Keywords: alternative fuel, biodiesel, bioethanol, heat engines, fuels blend
Published in DKUM: 31.05.2012; Views: 2554; Downloads: 0 |
4. Comparative study of various renewable fuels blends to run a diesel power plantEloisa Torres Jiménez, Marta Svoljšak, Andreja Gregorc, M. P. Dorado, Breda Kegl, 2010, published scientific conference contribution Abstract: In this paper bioethanol/diesel and bioethanol/biodiesel blends, at several concentrations and temperatures, are studied to find its possible commercial usage as a fuel to run a diesel power plant. The tested fuels were: net mineral diesel fuel (D100) , 5 % bioethanol/diesel fuel blend (v/v) (E5D95), 10 % bioethanol/diesel fuel blend (v/v) (E10D90), 15 % bioethanol/diesel fuel blend (v/v) (E15D85), neat biodiesel (B100), 5 % bioethanol/biodiesel blend (v/v) (E5B95), 10 % bioethanol/biodiesel blend (v/v) (E10B90), and 15 % bioethanol/biodiesel blend (v/v) (E15B85). The fuels were tested at: 30, 25, 8 and -18 C. This paper shows the observations done in 8 samples during 5 weeks. After each week, each sample was overviewed, and changes related to stability, colour and aggregation were recorded. It has been proved that additives are not necessary to ensure stability of bioethanol/biodiesel blends under low temperature conditions, as the phase separation never happens. But in case of bioethanol/diesel blends some additives are necessary to keep stability under low temperature conditions. Based on this study, it can be concluded that blends of biodiesel fuel with bioethanol up to 15% can be used to fuel a diesel power plant if engine performance tests corroborate it. The same conclusion can be applied to blends of diesel fuel with bioethanol up to 15% blends if additives to keep stability are added.
Keywords: alternative fuels, biodiesel, bioethanol, heat engines, fuels blend
Published in DKUM: 31.05.2012; Views: 2328; Downloads: 0 |
5. Diesel and biodiesel fuel spray simulationsPrimož Pogorevc, Breda Kegl, Leopold Škerget, 2008, original scientific article Abstract: This paper deals with the investigation of the influential parameters of a mathematical spray breakup model using different fuels. Beside injection system measurements, fuel physical properties and injection process characteristics were measured, because they are necessary for the spray simulation input. For validation purposes, spray was injected into motionless air at atmospheric pressure and room temperature and filmed with a high-speed camera. Spray macrocharacteristics have been determined on the recorded images. Using the simulation program, the injection processes for diesel, biodiesel, and their 50% blend B50 have been simulated. Spray mathematical model parameters were tuned based on the experimentally gained results. Primary breakup model parameters showed the biggest impact on the spray characteristics and were therefore expressed using the fuel physical properties, the injection process characteristics, and the working regime parameters. Spray simulations into the combustion chamber were made in the end. All of these results are presented and discussed in this paper.
Keywords: fuel spray, spray breakup, biodiesel fuel, fuels, numerical simulations, mathematical model
Published in DKUM: 31.05.2012; Views: 1952; Downloads: 88
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