Proper orthogonal decomposition analysis of an atomized fuel spray of marine diesel engine

Most marine vessels are powered by diesel engines. Unfortunately, fuel combustion releases harmful toxic compounds into the atmosphere. The International Maritime Organization (IMO) regulates these emissions, making their reduction essential for engineers and scientists. The fuel combustion process in a marine diesel engine's cylinder precedes the fuel spray injection and atomization. Fuel spray's flow fluctuations and vortex structures significantly impact the combustion. This paper presents research using the Mie Scattering optical technique to analyze snapshot sequences of spray patterns recorded with a high-speed camera. These snapshots are the results of experimental research on atomized fuel sprays with a marine diesel engine injector within a constant volume chamber. The influence of different chamber backpressures on the fuel spray is studied. The Proper Orthogonal Decomposition (POD) method is promising for quantitatively analyzing spray structures and flow characteristics. This research demonstrates how different chamber conditions affect the decay of the POD singular values, which typically indicate flow characteristics like coherence and fluctuations.