Abstract
Three-dimensional direct numerical simulation of hydrogen-air turbulent premixed flame in a larger constant volume vessel at relatively high Reynolds number has been conducted considering the detailed kinetic mechanism to clarify effects of pressure increase on dynamic characteristics of turbulent premixes flame. The DNS results in the larger volume vessel of this study and in a smaller volume vessel of our previous study have been compared to reveal effects of the vessel's size. The mean pressure in both the vessel reaches about 3 atm at the end of rapid combustion. Heat release rate of each flame element is augmented since the pressure increase makes flame thickness thin. The local pressure rise due to dilatation also enhances turbulence and finer scale vortices appear, which makes flame surface more complicated and results in increase of the flame surface area. The shape of the flame front becomes complicated and the meximum value becomes higher due to increase in pressure. By identifying flame elements in turbulence, the statistical characteristics are also discussed quantitatively.
