Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
VISUALIZATION OF VISCOPLASTIC FLUID FLOW IN AN ABRUPT CONTRACTION USING PARTICLE IMAGE VELOCIMETRY
Submission Author:
Yamid José García Blanco , PR
Co-Authors:
Yamid José García Blanco, Vitor Yoshiharu Urazaki, Admilson Franco, Eduardo Matos Germer
Presenter: Yamid José García Blanco
doi://10.26678/ABCM.COBEM2019.COB2019-0592
Abstract
Viscoplastic fluid flows through sudden contractions can be found in several industrial processes, such as polymer extrusion, food pumping, and drilling of oil wells. However, there are not enough experimental studies focused on the visualization of this kind of flow. This paper presents an experimental study of viscoplastic fluid flow in a cylindrical axisymmetric contraction facility (1.85 contraction ratio). Aqueous solutions with different weight percent of Carbopol are used as a viscoplastic fluid, characterized by the Herschel-Bulkley model. Particle Image Velocimetry (PIV) is used as a visualization technique to obtain detailed measurements of mean velocity, velocity fluctuations (axial and radial) and vortex structures generation. A stage for validation of the methodology used with the PIV technique was performed for water in a straight tube at turbulent flow conditions, and the data were compared with numerical and other experimental studies in the literature. For viscoplastic flow through the contraction was studied the mean axial velocity, the dependence of the appearance of vortex structure and unyielded zones in the contraction corners and the plug region, and the variation of the pressure losses with the increasing of Reynolds number. As the Reynolds number is approaching the turbulent regime, larger shear rates are generated at the contraction, reducing the area of the unyielded regions and promoting the appearance of large vortex structures at the corners of the abrupt contraction.
Keywords
Viscoplastic fluid, Herschel-Bulkley, Experimental Study, Contraction, PIV, unyielded
