Table 1: Experimental results.

Width of the annular gap 12 mm 6 mm 2.5 mm Mass flow rate at the outlet, kg/s Entrance is opened experiment 0.92 1.07 1.23 Entrance is opened calculations 1.19 1.61 2.51 Entrance is closed experiment 0.87 — 0.73 Entrance is closed calculations 0.70 0.70 0.70 Entrance is opened swirling jet calculations 1.62 1.52 2.83 Ejection coefficient Entrance is opened experiment 0.35 0.57 0.81 Entrance is opened calculations 0.75 1.37 2.69 Entrance is closed experiment 0.28 — 0.07 Entrance is closed calculations 0.00 0.00 0.00 Entrance is opened swirling jet calculations 1.31 1.17 3.04