Velocity field characteristics of turbulent jets from round tubes with coil inserts

Results of experimental investigations of turbulent jets from round tubes with coil inserts are presented. For the coils, the ratios of pitch spacing to the tube inside diameter, p/D, are 0.4, 0.7, 1.2, and 2.7 and the effective ratio of the coil wire diameter to the tube inside diameter, d/D, is 0.0275. Results show that the coils with large pitch spacing create a significant increase in the jetʹs mixing process and the mixing is more pronounced when p/D=1.2.