International Journal of Multiphase Flow, Vol.24, No.2, 243-269, 1998
Flow of concentrated non-Newtonian slurries : 2. Friction losses in bends, fittings, valves and Venturi meters
Friction losses for the how of concentrated slurries of laterite and gypsum through 2.5 and 5.0 cm bends, fittings, valves and Venturi meters were determined. The experimental work was carried out using a slurry flow facility consisting of several flow loops throughout which the different piping elements-had been installed. The friction losses for each piping element are based on detailed measurements of the axial pressure distributions along the element including that along upstream and downstream tangent lines consisting of long sections of straight pipe of the same diameter. Pressure losses for the fully-developed flow through straight pipe test sections were also measured to use as baselines. For flow through 45 degrees and 180 degrees bends, 90 degrees bends of different radii of curvature, and gate and globe valves, resistance coefficients, based on slurry density, were found to be inversely proportional to the generalized Reynolds number for laminar flow, and to approach constant asymptotic values for turbulent how. The fatter were the same as the high-Reynolds number limiting values for flow of water through the respective fitting. Correlations for resistance coefficients for slurry flow through concentric 5.0 x 2.5 cm(2) sudden contraction and 2.5 x 5.0 cm(2) sudden enlargement were also-established. Discharge coefficients for flow of slurries and water through 2.5 and 5.0 cm Venturi meters with throat to pipe diameter ratios of 0.5 and 0.75 were also determined. For slurries the discharge coefficients increased with increasing flow rate and approached asymptotic values at high flow rates which were the same as the values for highly turbulent flow of water.
Keywords:LAMINAR-FLOW;FLUID