Cycle-resolved computations of the turbulent premixed flame in an internal combustion engine are performed for a wide range of operating conditions, such as engine speed and air-fuel ratio. For this purpose, first a multilevel mathematical formulation, which is suitable for both the large-eddy simulation and direct numerical simulation of the compressible turbulence and combusting flows in engines is derived, and then a suitable numerical algorithm is developed. With this method, the transition to turbulence near the end of the compression process and the supergrid fluctuations of the physical quantities can be calculated with less CPU time. For determining the subgrid turbulence and flame wrinkling, respectively, the Yakhot-Orszag turbulence model based on the renormalization group theory and a flame-sheet model are incorporated in the numerical code. Calculations are performed for a real engine with dual intake port and valves. The simulated results agree well with the experimental data for both turbulence intensity and pressure history. Cyclic variations of the flow field and flame propagation are also calculated.
ASJC Scopus subject areas
- Computer Science(all)