The swirl is a measure of the angular velocity of the combustion air. It is characterized by the swirl number, S, defined as the ratio of the axial flux of angular momentum to the axial flux of linear momentum (Gupta et al., 1984).
Using the correlation suggested by Beer and Chigier (1972), the experimental conditions used here should result in a swirl number of S = 0.47. The reported value is based on the geometric dimensions of the burner and swirl vane cascade. See equations below.
Plans are underway to measure the swirl intensity at the burner exit.