Quasi-1D analysis of n-dodecane split injection processes
2022-01-0600
03/29/2022
- Content
- Split injection processes have been analyzed by means of a Quasi-1D spray model that has been recently coupled to a tabulated unsteady-flamelet progress-variable combustion model. The modelling approach can predict ignition delay and lift-off for long injection profiles, and it is now extended to a two-pulse injection scheme. ECN recommended operating conditions with a recent parametric study on split injection dwell and first injection duration have been investigated. In spite of the simplicity of the approach, as well as the transient injection profile, some important metrics such as tip penetration are adequately reproduced. In particular, the faster penetration of the second injection pulse compared to the first one is captured by the model both under inert and reacting conditions. While dwell has a clear effect on this acceleration, penetration of the second pulse does not seem to be affected by the first injection pulse duration. Local phenomena due to the interaction between both pulses are also adequately reproduced. The second pulse ignites much faster than the first one due to the injection into the remnants of the first one, where high temperature oxygen-depleted regions can be found. Ignition of the second pulse happens as soon as the first pulse reaches this region, with a faster low to high temperature transition. Parametric variations show a different influence of pulse dwell compared to first pulse duration. The latter variable seems to have a much lower effect on combustion development of the second pulse, because the near-nozzle region reaches a quasi-steady state quite fast. This results in almost identical conditions for the second pulse ignition, independently of the first injection duration.
- Citation
- Garcia-Oliver, J., Novella, R., Pastor, J., and Cao, J., "Quasi-1D analysis of n-dodecane split injection processes," SAE Technical Paper 2022-01-0600, 2022, .