Two-phase flow in inclined parallel pipes

Two-phase flow in parallel pipes is associated with the application of Direct Steam Generation by solar heating. In this process boiling water is fed into many parallel pipes from a common manifold. Instability and non-uniformity of the flow in this case can be a major operational problem. In this work the gas and liquid distribution in two parallel pipes is mapped experimentally. It is found that the flow distribution can be either symmetric or asymmetric depending on the flow conditions and pipe inclination. A model that explains the observed phenomena is proposed.