Optical Reconstruction of Wavy Interface between Stratified Liquids: Experiment and Instrumentation
Presence of stratified flow configuration is very common in chemical, material processing, petroleum and nuclear industries. Among different patterns, depending on flow velocities, one can find stratified association of phases keeping denser one at bottom. With increase of relative velocities between the phases, interface turns out to be wavy which may shed droplets in favorable interfacial tension. Here, we present an idea of linear array of optical sensors with corresponding light emitters to characterize the stratified interface between kerosene and water. Sensor array and light source are placed in centre plane of the test section from bottom to top orientation, respectively. The test section is having L/a ratio of 80 with its inlet, equally shared by both the phases. Optical measurements are taken at x/a ratio of 40 from inlet to ensure fully developed flow during the non-intrusive inspections. Sensitivity of the proposed optical system is tested by allowing different fluid mediums (kerosene and water) through the test section. Maximum signal is obtained for water and reduction in current is observed on introduction of kerosene flow through the test section. The present study proposes the utilization of inherent properties of the optical sensors to correlate signal with different fractions of kerosene and water obtained by varying interface height. Decay in output signal can be seen on inclusion of kerosene. The main idea of the present work is to employ the variation of optical signals towards obtaining interface height at different axial locations along the length of test section and to construct the interface using interpolation algorithms. Wave parameters like its amplitude, wavelength and velocity can also be derived using the obtained signals. The present study will find its applications in the area of two phase flow measurements.