FLOW IN THE STAGNATION ZONE DURING SUBMERGED INJECTION OF A SWIRLING GAS-JET

A solution, corresponding to submerged injection of a swirling gas jet into a liquid, is obtained for inviscid gas flow together with the shape of the gas-liquid interface (assumed to be sharp) near the stagnation point beneath the jet. The velocity distributions near the axis of the jet are assumed to be known and to correspond to those in a free jet independent of the presence of the interface. Based on published swirling jet velocity data, predicted depth of jet penetration and interface curvature at the stagnation point are shown as functions of the swirl number (S) and flow rate. At high swirl the predicted interface is inverted (concave downwards), consistent with observation, and occurs when the maximum jet axial velocity is displaced from the centre-line. At low swirl (S ≤ 0.1), the jet penetration depth is predicted to have an initial quadratic dependence on flow rate (consistent with published data in the absence of swirl) which becomes linear when the flow rate is large enough. At moderate to high swirl (0.2 < S < 0.6) only a linear dependence is predicted. © 1990.