Proper design of swirlers to obtain short flames is one of the important points for developing residential combustion appliances requiring compactness.
As the first step, the flow visualization experiments using water and blue dye for the simple conventional low-pressure atomizing gun type burner were performed in order to obtain some qualitative information on flow patterns. Based on the flow visualization, a test swirler for a gas blast type burner (GB-burner) was designed and fabricated.
As the second step, mixing characteristics for the GB-burner were quantitatively obtained by salt tracer technique.
As for condition of similarity between actual mixing process and that of the model, the Reynolds number and momentum ratio of air to fuel of the model were equalized to those of practical burner respectively.
On applying these results of modeling to the practical burner, three basic factors related to the fast diffusion of the fuel, the distribution of time-averaged concentration of the fuel and the existence of a high r. m. s. concentration of the fuel around the swirler were discussed.
We found it reasonable to apply the modeling based on the three factors for designing the burner and confirmed that good mixing characteristics are forerunner for obtaining good combustion characteristics.