On the analysis of propane jet flames in mutual interaction

The characteristics of attached non-premixed jet flames in mutual interacti on are studied experimentally through the analysis of 1, 3 and 5 propane fl ames with an individual Reynolds number of 20400. Laser Doppler velocimetry , fine-wire thermometry and chemical species concentration analysis were us ed to characterise the flame systems, as well as simultaneous acquisition t echniques to obtain information on the scalar turbulent behaviour. The results show that, although the turbulent mixing pattern is altered by changes in the mean flow characteristics, the concentration of major chemic al species and temperature fields remain qualitatively unaltered at the lev el of flame interaction studied here. The present results quantify the exte nt to which turbulent transfer is modified in the interaction zone, though oxygen insufficiency is the controlling mechanism in the propagation of fla mes in mutual interaction. The analysis shows that turbulent heat fluxes te nd to be restricted to the mixing layer where large temperature gradients o ccur. Otherwise, they exhibit larger component directed along the isotherms , as for single flames. This behaviour suggests that the process of turbule nt transport is unaltered at the level of flame interaction considered in t his paper.