Experimental study of dispersed oil-water flow in a horizontal pipe with enhanced inlet mixing, Part 2: In-situ droplet measurements

Droplet size measurements in premixed oil-water flow are presented. Three traversable focused beam reflectance measurement probes (FBRM) positioned along the test section allowed for measuring averaged droplet size profiles over the cross section. Measurements for two mixture velocities, Umix=0.5 m/s and Umix=1 m/s, and the complete range of input water fractions were performed with tap water and medium viscosity mineral oil. The flow facility provided a 10 cm inner diameter test section of 24 m total length. Flow development in terms of droplet growth was documented. Averaged droplet sizes showed to be a function of the dispersed phase fraction with sizes increasing towards a maximum at phase inversion. Different flow patterns show characteristic droplet size profiles over the cross-section. Common models over-predict the presented droplet size data, most probably as a result of enhanced inlet mixing and underdeveloped flow.