A Comparison of Isobaric and Conventional Diesel Combustion using High-Speed Optical Imaging
2022-01-0499
03/29/2022
- Event
- Content
- Isobaric combustion can achieve higher thermal efficiency, lower heat transfer losses, and NOx emissions compared to conventional diesel combustion (CDC). Previous studies on isobaric combustion provided a detailed analysis of performance/emissions characteristics with a limited emphasis on the fuel-air mixing process, high-temperature reaction, and soot formation zones. In the present study, high-speed imaging of Mie-scattering, CH* chemiluminescence, and soot luminosity were conducted in an optically accessible single-cylinder heavy-duty diesel engine for CDC and isobaric combustion. The fuel used for both the combustion modes is n-heptane, which is a surrogate of diesel fuel. The engine was equipped with a flat-bowl shaped optical piston to allow bottom-view imaging of the combustion chamber. The peak cylinder pressure (PCP) and the fuel mean effective pressure (Fuel MEP) for both the combustion modes are kept as 70 bar and 19 bar, respectively. For a given combustion mode, the liquid-phase spray penetration length, flame speed, and soot intensity were calculated from the Mie-scattering, CH* chemiluminescence, and soot luminosity imaging, respectively. Flame image velocimetry (FIV) analysis was also performed on the soot luminosity images to obtain in-flame flow field details and was compared to the CDC.
- Citation
- Panthi, N., Goyal, H., and Magnotti, G., "A Comparison of Isobaric and Conventional Diesel Combustion using High-Speed Optical Imaging ," SAE Technical Paper 2022-01-0499, 2022, .