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1

Cavitation phenomena in the injection nozzle: theoretical and numerical analysis

Volmajer M., Kegl B.

Journal of KONES

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2004

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Vol. 11, No. 3-4

295-303

2

Analysing in-nozzle flows using partial nozzle models

Volmajer M., Kegl B.

Journal of KONES

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2003

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Vol. 10, No. 1-2

289--296

EN

The geometry of the diesel fuel injection nozzle and fuel flow characteristics in the nozzle significantly affects the processes of fuel atomisation, combustion and formation of pollutant emissions in a diesel engine. To improve the processes of fuel injection and spray formation CFD packages are commonly used. Since CPU times are often high, partial models are used for analysis. The results of the analysis by using partial models are model dependent, so the differences between the results using different models can occur. In this paper CFD analysis for different partial models of a 4-hole nozzle were made. The objective of the research was to find the proper model to be used for fast analysis of existing nozzle geometry. Several partial models of the nozzle were made. The results were compared with the results of measurements at steady state conditions.

3

Injection characteristics of an in-line fuel injection system using the alternative fuels

Volmajer M., Kegl B., Pogorevc P.

Journal of KONES

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2002

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Vol. 9, No. 1-2

259-267

EN

The ever increasing ecological requirements encourage the use of alternative fuels. Some alternative fuels have advantages in production, some in transport and some in excellent injection as well as engine characteristics. Till today several alternative fuels for compression ignition engines have been investigated. This paper deals with the bio-diesel and with the wasted cooking oil. Biodiesel is produced from different plants (rape, Canola, Soya beans, palm tree...), while the wasted cooking oil is received from the catering industry. In this paper attention is focused on the fuel injection as well as fuel spray characteristics using diesel, bio-diesel and wasted cooking oil. The analysis of the fuel injection characteristics is obtained using the one-dimensional mathematical model for numerical simulation of injection process. In this model the influence of the snubber valve, the cavitation phenomena as well as variable fuel properties are taken into account. The influence of alternative fuels on spray characteristics is investigated using some empirical models. Furthermore, a computational fluid dynamics package is used for some analyses of the nozzle flow characteristics. Finally, on the basis of the numerically and experimentally obtained results, the harmful emissions using alternative fuels are predicted to some extent.

4

Experimental and numerical analysis of fuel flow in the diesel engine injection nozzle

Volmajer M., Kegl B.

Journal of KONES

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2001

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Vol. 8, No. 1-2

9-16

EN

The geometry of the diesel fuel injection nozzle and fuel flow characteristics in the nozzle significantly affects the processes of fuel atomisation, combustion and formation of pollutants emissions in a diesel engine. In this paper numerical and experimental results of the nozzle fuel flow analysis for a four-hole injection nozzle Bosch DLLA 148 S 311376 are presented. To describe the nozzle fuel flow, a three-dimensional computational fluid dynamics (CFD) model is employed. The CFD package FIRE (AVL Graz) is used for computation. The results represent the fuel flow characteristics for steady state flow conditions at different needle opening. For this purpose several three-dimensional models representing different needle lifts are made. The experimental results are obtained by measuring the fuel flow coefficients at steady state conditions on the nozzle flow tester made in Engine research laboratory (ERL) at the Faculty of mechanical engineering in Maribor. The fuel injection pump is driven by an electric motor, the pressure control valve regulates the pressure at 100 bar and the calibration fluid is injected through the nozzle into the measuring Plexiglas cylinder. The fuel flow coefficients obtained from the experimental results at steady flow conditions in the nozzle are compared with the results of the CFD analysis.