Dual Fuel Combustion in an Optically Accessible Engine 2020-01-0309
The engine fueled with methane/diesel is a promising and highly attractive operation mode due to its high performance-to-cost ratio and clean-burning qualities. However, the combustion process and chemical reactions in dual fuel combustion are still not fully understood. The motivation of the current investigation is to gain an insight into the combustion dynamics in dual fuel combustion engine based on chemiluminescence species and thermal radiation. The chemiluminescence and natural luminosity (NL) are expected to provide specific characteristics in combustion control and monitoring. To visualize the highly unsteady combustion process in terms of OH*, CH2O* and CH* radicals and luminous soot emissions, the band filters with 308nm, 330nm and 430nm were employed for visualization of chemiluminescence at different cycles. High speed natural luminosity imaging was adopted to illustrate the effects methane lambda on the ignition delay, luminous intensity and engine performance. Spectroscopy analysis based on OH*, CH2O* and CH* was performed to study the chemical reactions in diesel only and dual fuel mode. The last case compared the temperature distributions in diesel-only mode and dual-fuel mode based on a high-speed color camera.
Qiang Cheng, Zeeshan Ahmad, Ossi Kaario, Martti Larmi