Effects of inclination and rolling on interfacial parameter distributions of bubbly flow in a rectangular duct

Effects of inclination and rolling on lateral distribution of interfacial parameters for bubbly flow were studied experimentally with the help of a high-speed camera. Local parameters such as bubble proportion, void fraction and interfacial area concentration (IAC) were obtained in the experiments, showing a similar character with each other. These local parameters change slightly in the central part of the duct and present peaks around positions of x_i/(w/2)=±0.5 (x_i represents the distance from origin based on the central axis of wide side to the inner wall surface of the narrow side, w denotes the wide side) in vertical position for both motionless and rolling cases. The peak of local parameters near the lower wall region is weakened and that near the upper wall is enhanced with an increase in inclined or rolling, angles. There exist no obvious differences of interfacial parameters in lateral distribution at the same angle under inclined and rolling conditions within the range of experimental rolling parameters, which is mainly due to that the additional inertial force in lateral direction induced by rolling motion is far more less than that of buoyancy. (authors)