Experimental study of a single elongated bubble in liquid in under 10-degree upwardly inclined pipes

Abstract Two phase flow is of great interest in chemical and petroleum industries, multiphase pipe models with closure relationships require experimental data for their development validation. However, only little information available slightly upward inclined pipes. Experimental investigations single elongated bubble marginally upwardly pipes less than 10° have therefore been performed. Observations the drift velocity along has highlighted. The presented here can contribute to improve knowledge inclination viscosity dependency correlations. new on characteristics - shape, length, fraction may also provide useful validation numerical models. measured compared some recently developed