Degassing of water-solved gases in thin pipings during fast pressure drops

A one-dimensional model is presented, which describes the transient two-pha se flow in thin pipes during fast pressure drops and degassing by use of Eu lerian and Lagrangian systems. The reduction in dimension is obtained by in troduction of a geometry model for bubbly and slug flow regimes. The comple te model includes the transient two-phase flow, bubble formation and bubble growth. The flow model predicts rising velocities of bubbles and plugs in arbitrary inclined highly accurate pipes. The mass transfer (diffusion) of the dissolved phase is calculated by the bubble growth model. The quality o f the model was examined by simulation of experimental series, whereby wate r was depressurised from the saturation pressure of the dissolved gas mixtu re lair), by variation of saturation pressure, pressure gradient and pipe g eometry. The results of numerical simulation fit the experimental data well .