Waves and Secondary Flows in Stratified Gas/Liquid Duct Flow

Abstract

When a gas and a liquid flow co-currently through a horizontal duct, stratified flow occur at fairly low flow rates with the heavier liquid flowing along the bottom of the duct and gas above the liquid. The stratified flow regime has been studied by several researchers. Hanratty and Engen (1957), Akai, Inoue and Aoki (1977) and Suzanne (1985) all reported similar flow condition for transitions to the stratified regime in horizontal and near horizontal duct flow. The stratified regime is usually divided into two main sub-regimes: The stratified smooth and the stratified wavy regime. The flow is turbulent in the stratified wavy regime, and the interface between the gas and the liquid is characterized by complicated wave patterns. This regime has been divided into several new sub-regimes according to the wave structure, which for some flow rates may be fairly regular. There is a considerable amount of experimental data on the interfacial wave structure in the stratified wavy flow regime, but very few researchers have studied both the wave field and the three dimensional flow field in the same experiment. Suzanne (1985) is one of these few. He reported that for certain gas and liquid flow rates a fairly regular wave pattern occurred accompanied by strong transverse mean flow. His experiment was conducted in a duct with rectangular cross section