Refined reconstruction of liquid-gas interface structures for oil-gas stratified two-phase flow using wire-mesh sensor

Wire-Mesh sensors (WMS), developed at HZDR [1], are potential tools to measure phase fraction distributions quantitatively and visualize two-phase pipe flow phenomena with a very high temporal resolution. They have been extensively applied to a wide range of two-phase gas-liquid flow situations with conducting and non-conducting liquids. However, for very low liquid loadings the state of the art data evaluation algorithms for WMS data suffer under the comparable low spatial resolution and under boundary effects, caused by the flange rings - especially in case of capacitance type WMS. Recently, a pair of capacitance WMS with 32x32 wires has been applied to study interfacial wave characteristics in stratified-wavy configuration for air-oil two-phase flow at Tulsa University Fluid Flow Projects (TUFFP) in a 6-inch ID low pressure flow loop. The superficial liquid and gas velocities for these experiments vary between 9.2 m/s ≤ νSG ≤ 15 m/s and 0.01 m/s ≤ νSL ≤ 0.02 m/s, respectively [2]. To understand the flow phenomena of the stratified wavy structure an accurate reconstruction of the liquid-gas interface is essential. Due to the comparable low spatial resolution of app. 5 mm, the liquid-gas interface recognition has always an unknown uncertainty level since a specific threshold level for the ISO-surface has to be applied. In this work a new algorithm for refined liquid-gas interface reconstruction is introduced, using a-priory information in case of completely stratified flow situations.