Abstract
The dual-fuel (DF) combustion concept is one of the promising strategies for modern automotive and marine engines to achieve lower emission levels. A premixed DF engine operates by having a pilot diesel injection to ignite the lean premixed natural gas in the engine. Experimental studies on premixed DF combustion with micro pilot diesel fuel are limited. Hence, the underlying mechanism are still not well-understood. In this study, a three dimensional (3D) computational fluid dynamic (CFD) study is performed using the Simcenter Star-CCM+ software to investigate the ignition characteristics of the premixed DF combustion. Large eddy simulation (LES) is used for the turbulence modelling in the current work. The numerical simulation is carried out by modelling the injection of the pilot diesel fuel into a constant volume bomb with a premixed methane-air mixture. The adaptive mesh refinement (AMR) is implemented in order to
increase the computational efficiency. The minimum cell size is set to 0.25 mm. N-dodecane fuel is used as a pilot diesel surrogate fuel. Two reduced n-dodecane chemical mechanisms, i.e. Yao53 and Lapointe63, are being tested. Model validation is carried out by comparing the liquid penetration length (LPL) of the inert diesel spray to the measured data. The predicted ignition delay time (IDT) in the pure diesel case and the DF case are also validated against the available experimental data. Both mechanisms are able to capture the ignition process in the pure diesel case with reasonable accuracy, with the Lapointe63 mechanism having relatively better performance. However, only Lapointe63 is able to capture the ignition process in the DF case. The discrepancies observed in the simulation results may be attributed to the mechanism itself and the assumption that premixed methane/air is homogeneously mixed
increase the computational efficiency. The minimum cell size is set to 0.25 mm. N-dodecane fuel is used as a pilot diesel surrogate fuel. Two reduced n-dodecane chemical mechanisms, i.e. Yao53 and Lapointe63, are being tested. Model validation is carried out by comparing the liquid penetration length (LPL) of the inert diesel spray to the measured data. The predicted ignition delay time (IDT) in the pure diesel case and the DF case are also validated against the available experimental data. Both mechanisms are able to capture the ignition process in the pure diesel case with reasonable accuracy, with the Lapointe63 mechanism having relatively better performance. However, only Lapointe63 is able to capture the ignition process in the DF case. The discrepancies observed in the simulation results may be attributed to the mechanism itself and the assumption that premixed methane/air is homogeneously mixed
| Original language | English |
|---|---|
| Title of host publication | Proceedings - 15th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics |
| Publisher | American Society of Thermal and Fluids Engineers |
| Publication date | 2021 |
| Pages | 1628-1633 |
| Publication status | Published - 2021 |
| Event | 15th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 21) - Virtual conference Duration: 25 Jul 2021 → 28 Jul 2021 |
Conference
| Conference | 15th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT 21) |
|---|---|
| Location | Virtual conference |
| Period | 25/07/2021 → 28/07/2021 |
Keywords
- Premixed dual-fuel
- Methane gas
- Premixed dual-fuel, Methane gas, Pilot diesel injection, Large eddy simulation, Constant volume combustion chamber
- Large eddy simulation
- Constant volume combustion chamber
