Two Phase Flow in Pipes: Flow patterns of (air-water) two phase flow that effect in vertical and horizontal pipes with 90 elbow

Studying flow patterns that formed during the two phase flow is great importance in many industries, for example, the petroleum, chemical, nuclear and geothermal industries . Oil extraction operations is one of both offshore and onshore.Two-phase flow is part of a multiphase flow because it consists of two materials and classified as a homogeneous system, for as air-liquid, air-solid or as a heterogeneous system, for liquid-liquid and liquid-solid. It is considered to be an unsteady flow and it is more complex than single phase flow due to the difference between the material properties in each phase. Air-Liquid flow is a homogeneous flow but at the same time it is considered as an unsteady flow due to difference between the compounds of the material in each phase. It contains more than one phenomenon at the flow in vertical and horizontal pipes with 90 elbow depending on superficial velocity of air Usa and superficial velocity liquid Usl. The value of the density ρ and viscosity μ of the homogeneous mixture flow calculated depending on the value of the holdup or void fraction are denoted as (β and α) and this value is different from pattern to another.