Visualization and analysis of a pilot spray in a medium-speed dual-fuel engine
Westerlund, Eddie (2023)
2023
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe20231208152521
https://urn.fi/URN:NBN:fi-fe20231208152521
Tiivistelmä
Improving the internal combustion engine is a constant requirement for the marine industry. The development of renewable energy sources, alongside with advancements in the engine, is crucial. Implementing research methods such as optical visualizations has accelerated the development of internal combustion engines. This study aims to use optical techniques to successfully measure the fundamental spray characteristics of a Wärtsilä medium-speed large-bore engine injector and use the in-cylinder conditions of the engine to identify any potential deviations.
This thesis provides an overview of the implementation of the shadowgraph, and backlight optical technique in an industrial Optical Spray Combustion Chamber. It utilizes existing research on optical techniques in combustion engines, how to apply them to study specific spray characteristics, and how to post-process captured videos using MATLAB coding. The spray characteristics studied in this thesis are the spray penetration, area, cone angle, and velocity.
In-cylinder conditions were incorporated into a test matrix to ensure accurate measurements of all test points and a comprehensive study of all spray characteristics. The spray characteristics were captured in three different combustion modes: non-reactive non-evaporative spray, non-reactive evaporative spray, and reactive evaporative spray.
The results indicate reasonably accurate repeatability across all cases. A higher density in the chamber resulted in lower penetration and area of the spray. The cone angle of the spray increased with higher chamber density and decreased with lower density. The peak velocity was between 300-1200 m/s in all combustion modes. The penetration and area of the spray were slightly greater in a reactive spray compared to a non-reactive and non-evaporating spray. Otherwise, the combustion mode did not significantly alter the spray characteristics, as there were no major changes in the characteristics of a reactive spray compared to the non-reactive spray.
This thesis provides an overview of the implementation of the shadowgraph, and backlight optical technique in an industrial Optical Spray Combustion Chamber. It utilizes existing research on optical techniques in combustion engines, how to apply them to study specific spray characteristics, and how to post-process captured videos using MATLAB coding. The spray characteristics studied in this thesis are the spray penetration, area, cone angle, and velocity.
In-cylinder conditions were incorporated into a test matrix to ensure accurate measurements of all test points and a comprehensive study of all spray characteristics. The spray characteristics were captured in three different combustion modes: non-reactive non-evaporative spray, non-reactive evaporative spray, and reactive evaporative spray.
The results indicate reasonably accurate repeatability across all cases. A higher density in the chamber resulted in lower penetration and area of the spray. The cone angle of the spray increased with higher chamber density and decreased with lower density. The peak velocity was between 300-1200 m/s in all combustion modes. The penetration and area of the spray were slightly greater in a reactive spray compared to a non-reactive and non-evaporating spray. Otherwise, the combustion mode did not significantly alter the spray characteristics, as there were no major changes in the characteristics of a reactive spray compared to the non-reactive spray.