Concentration Field of Passive Scalar in a Multi-Phase Plume: Experimental Study on Applying of the 3D-PLIF Technique and Its Application for Design of Subsea Injection System of Dispersant

Abstract

In this research, we used experiments to measure the passive concentration field inside a multi-phase plume with an application to help design an injection system for subsea injection of dispersant during an accidental blowout. 3D Planar Laser Induced Fluorescence (3DPLIF) technique was adapted to study the spatial distribution of the concentration field created by different types of injectors. This technique requires new correction processes to account for the presence effects of the immiscible particles in the field of view. We used the developed method to measure the concentration field inside a bubble plume with different flow rates to investigate the effects of different injectors on the characteristics of the passive scalar concentration field. We derived new correction processes to convert fluorescent light intensity to concentration, such as an image processing method to detect and remove the signature of bubbles and shadows from an image and an object detection method to specifically find bubbles and calculate the presence probability inside the bubble plume. Based on the bubble concentration, the laser attenuation can be estimated, which is required for accurate concentration measurements. We used our developed 3D-PLIF technique to measure the concentration field created by three types of injector: single point, wand, and collar diffusor to study the effects of injection geometry as well as injection position on the characteristics of the concentration field.