Hydraulic Transport of Sand and Lime Slurries in a Vertical Pipeline

Abstract

<p>This thesis is primarily concerned with the energy required to hydraulically transport sand and lime slurries in a 5.1 cm.-diameter vertical pipeline for both steady and pulsating flows.</p> <p>In the steady flow experiments, three different grades of sand of average weighted diameter d = 0.66, 1.20 and 1.84 mm. were investigated. The lime flurry used had an average particle diameter of 1.8 x 10⁻³ mm. The delivered volumetric concentration C₅, the average mixture flow rate Q, and the pressure difference ΔP across the test section were measured within the Reynolds number range of 4 x 10⁴ to 2 x 10⁵.</p> <p>In the pulsating flow experiments, only one grade of sand of average weighted diameter d = 1.20 mm. was investigated at frequencies of 0.22 and 0.44 cycles per second.</p> <p>Two methods of predicting pressure gradient for slurry flow were attempted. The first was adapted from Newitt et. al. (1961). By comparing the measured pressure gradient i for various suspensions to those for water flowing under similar conditions iw, an excess dimensionless pressure parameter Φ was obtained. It was possible to correlate the steady flow data using Φ and another dimensionless parameter Ψ related to mixture velocity Vm, diameter ratio D/d and specific gravity of solid S. In the second method the excess pressure gradient (i-iw) is equated to the excess hydraulic head CT(S-1). The results are presented in graphical form and each method is appraised in the discussion.</p> <p>The energy dissipated per unit height of the test section and mass flow rate was determined for steady and pulsating flow of suspensions. The energy ratio JP/Js at the two frequencies was obtained for low concentration slurries (Cs < 8.0%). It was found that no energy savings were recorded for pulsatile flow under these conditions.</p>