Features of the flow structure in the mixing chamber of the Coanda ejector

The experimental results on the study of the flow structure and pressure distributions on the wall and along the axis of the Coanda ejector mixing chamber are presented. The experiments were carried out in the range of changes in the absolute value of the total pressure in the prechamber PK = 1.2 – 3.5 atm, which corresponded to both sub- and supercritical jet outflow regimes. The width of the annular gap through which the ejector flow was blown into the mixing chamber took the values h = 0.15, 0.25 and 0.5 mm. An increase in the vacuum on the wall in the initial part of the nozzle was observed with an increase in the total pressure. It was found that the static pressure distributions along the nozzle axis are characterized by the presence of a vacuum region almost along the entire length of the cylindrical channel. At subcritical jet outflows, recirculation zones can form in the vicinity of the channel axis near its inlet. A fundamentally different character of the velocity distribution and pulsation intensity in the cross section of the mixing chamber is noted, depending on the outflow regimes.