Two-Phase (Solid-Liquid) Flow in Inclined Pipes

this paper presents an experimental research about the behavior of two-phase flows in inclined pipes. the inclination angle varied from 5° to 45° and the slurry solid concentration varied up to 15%. it was concluded that the head losses of the downward sloping pipe flow are always lower than the head losses of the horizontal flow and these are always lower than the head losses of the upward sloping pipe flow, regardless the concentration and inclination angle. it was possible to develop empirical equations to calculate the head losses of the horizontal flow and the upward and downward sloping pipe flows.