Chapter VII - Complex and Slurry Flow Measurement

Abstract

Fluid classifications as per continuum mechanics and rheology, for Newtonian and non-Newtonian fluids are discussed in this chapter to identify the characteristic features for slurries and complex fluids. Viscoelastic and viscoplastic materials, including paste with memory and characteristic features, are discussed. Discussions on deformation forces, yield stress, the nature and kinds of deformations of fluid are covered to give an understanding of the flow of slurries and complex fluids. Slurry flow classification is presented to include the discussions on particle types, shape settling, and nonsettling slurry characteristics with slurry flow characteristics of slurry flow regimes including homogeneous and heterogeneous slurry flow with moving and stationary beds. Various flow instruments, such as differential pressure (DP) types, including Venturi, wedge, turbine types, positive displacement (PD) meters, magnetic flow meters, ultrasonic flow meters, and Coriolis flow meters with special focus on design modifications necessary for flow measurements of slurry and complex fluids. Major issues include dual-frequency excitation systems of magnetic flow meters, and the application of SONAR meters for the same. Detailed discussions have been presented on applications of different instruments for slurries in different plants including drilling, paper, and alumina plants. Detailed discussions are also presented on wedge elements. Starting with the working principles, variations of wedge element characteristics with wedge ratio are described. Also, details on the mounting of wedge meter installations are covered.