Theoretical framework and high-fidelity direct numerical simulations (DNS) on preignition and knock encountered in internal combustion (IC) engines are briefly reviewed in this chapter. The theoretical framework is presented first, and systematically followed by one-dimensional and multi-dimensional simulations. A number of high-fidelity simulations under realistic IC-engine conditions were used to demonstrate the super-knock mechanism in the presence of the complex chemistry-turbulence interaction. The ratio of ignition delay time to eddy-turnover time, τig/ τt, and the ratio of the most energetic length scale of turbulence and temperature fluctuations, lt/ lT, affect the knock intensities are discussed. Different statistical metrics extracted from the multi-dimensional simulations to predict knock intensity are also presented. The quantitative determination of strong and weak ignition modes using the predicted Sa-based metrics is also cover in this chapter.
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Industrial and Manufacturing Engineering
- Management, Monitoring, Policy and Law