EXPERIMENTAL STUDY OF THE CORRELATION FOR TURBULENT BURNING VELOCITY AT SUBATMOSPHERIC PRESSURE.

Turbulent burning velocity is one of the most relevant parameters to characterize the premixed turbulent flames. Different correlation has been proposed to estimate this parameter. However, most of them have been obtained using experimental data at atmospheric pressure or higher. The present study is focused on obtaining a correlation for the turbulent burning velocity using data at sub-atmospheric pressure. The turbulent burning velocity was experimentally calculated using the burner method, where turbulent premix flames are generated in a Bunsen burner. Stoichiometric and lean conditions were evaluated at a pressure of 0.85 atm and 0.98 atm, whereas the turbulence intensity was varied for each condition. Perforated plates and a hot-wire anemometer were used to generate and measure the turbulence intensity. Schlieren images were used to obtain the average angle of the flame and calculate the turbulent burning velocity. Experiments and theory show that the turbulent deflagration rate decrease as pressure decrease. The turbulent deflagration speed decreased by up to 16 % at 0.85 atm concerning atmospheric conditions for the same turbulence intensity, discharge velocity, and ambient temperature, according to the experimental results. The comparison among the experimental results at sub-atmospheric conditions and the correlations reported in the literature exposes prediction issues because most of them are fitted using data at atmospheric conditions. A general correlation is raised between turbulent burning velocity (ST), laminar burning velocity (SL) and turbulence intensity (u′) proposed from the experimental data. This correlation has the form ST/SL ∝α [ur/SL]n. For sub-atmospheric and atmospheric conditions, the coefficients were determined. [ABSTRACT FROM AUTHOR]