Characteristics of two phase flow composed of air and viscous liquid in pipes were investigated. Pressure drop in horizontal pipes was measured for some working fluid pairs such as viscous oil/air or viscous polymer/air. Test results showed good agreement with the Lockhart-Martinelli equation in a range of viscosity up to several thousand cP. It was found that water added to the two phase flow drastically decreases the pressure loss. In addition to the pressure drop measurements, suction experiments using several types of suction inlets were carried out and a basic design concept for the shape of the inlet was obtained.
