3D Simulationson Premixed Laminar Flame Propagation of iso-Octane/Air Mixture at Elevated Pressure and Temperature

This paper aims to validate chemical kinetic mechanisms of surrogate gasoline three components fuel by calculating one-dimensional laminar burning velocity of iso-octane/air mixture. Next, the application of level-set method on premixed combustion without consideration the effect of turbulence eddies on flame front is also studied in three-dimensional computational fluid dynamic (3D-CFD) simulation. In the 3D CFD simulation, there is an option to calculate laminar burning velocity by using empirical correlations, however it is applicable only for particular initial pressure and temperature in spark ignition engine cases.

One-dimensional burning velocities from lean to rich of iso-octane/air mixture are calculated by using CHEMKIN-PRO with detailed chemistry and transport phenomena as a function of different equivalence ratios, different unburnt temperature and pressure ranges. A set of laminar flame table is then combined with 3D-CFD calculations with chemical kinetic mechanisms to track flame front displacements. A high-speed video camera at a frame speed of 2000 frames/sec is used to record the experimental flame positions of iso-octane/air combustion in a cylindrical shape constant volume combustion chamber (CVC). Different fuel-air equivalence ratios ϕ from lean to rich mixtures, ranging from 0.8 to1.4, are investigated at initial temperature of 420 K and 0.3 MPa of ambient pressure. The coupled simulations of one-dimensional adiabatic laminar burning velocity and 3D-CFD well predicts thermodynamics analysis of pressure-time and rate of heat release-time history and visualizations of flame front positions. Temperature and chemical species distributions of flame reaction zone are reported in comparison to that of experiments.