Turbulence characteristics in Internal Combustion Engines

The velocity of gas flow in the combustion chambers of two engines was measured, and the turbulence characteristics were investigated. It is shown that the auto-correlation coefficient of the fluctuating component of velocity and the normalized one-dimensional energy spectral density of turbulence are nearly determined by the integral time scale of turbulence and the turbulence Reynolds number, and the approximate expressions for the auto-correlation coefficient and energy spectral density are presented. Moreover, the relationship between the turbulence Reynolds number and the mean flow Reynolds number is examined, and the structure of the turbulent flow in engine combustion chambers is discussed.