Turbulence Structures in Horizontal Two-Phase Flows Under Counter-Current Conditions

In order to improve the multi-dimensional numerical simulation of horizontal two-phase flows, the knowledge of local turbulent quantities is of great importance. In horizontal stratified flows, the denser (first) phase flows as a film beneath the other (second) phase. Under counter-current conditions, the second phase flows into the opposite direction of the first phase. In the present investigations a liquid film flows counter-currently to a gas flow. According to the flow rates of both phases, different flow regimes set in. In supercritical flows (Fr>1), the height of the liquid film increases in flow direction, while it decreases in subcritical flows (Fr<1). For sufficiently high gas flow rates the upper part of the liquid film flows into direction of the gas flow, while the lower part still flows into its initial direction opposite to the gas flow. Only a reduced amount of water reaches the end of the test section. This flow regime is referred to as partially reversed flow. The presented local measurements provide not only the mean and rms-velocities of the liquid film, but also the corresponding Reynolds stresses. Local measurements are carried out at two different positions along the test section for various boundary conditions. Furthermore, the liquid injection height has been varied. The kinematic and turbulent structures of the different flow patterns are presented and compared.