Effect of turbulence on spatial distribution and group behavior of dropletin a spray flame

This paper presents results of the study on the effect of turbulence on dro plet dispersion and group behavior in liquid-fuel spray flame. Insertion of grids with different mesh sizes in front of the nozzle resulted in change of turbulence intensity, while the change of turbulence integral scale was negligible. For smaller mesh and lower turbulence intensity total vaporizat ion rate is rapidly increasing, while the droplet size distribution remains practically unchanged. Measurements of combustion group number showed that decrease of average group combustion number is well correlated with increa se of vaporization rate. Therefore, the reason for observed vaporization en hancement, could be explained by more uniform spatial distribution and weak er inter-droplet interactions, which usually strongly reduce vaporization r ate of droplets in dense sprays. Contrary to observed increase of vaporizat ion rate, flame length is growing. This phenomenon is attributed to reducti on of mixing of evaporated fuel and ambient air for lower turbulence intens ity and poorer mixing between two gaseous phases compared to mixing between the air and droplets in liquid phase.