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John M. FurlanGIW Industries, USAPresented by:John M. Furlan
Pumping a 100‐600 Pa Yield Stress Clay Slurry with a Centrifugal Pump
Robert J. VisintainerGIW Industries, USA
Anders SellgrenLulea Univ. of Tech., Sweden
Effects of Non‐Newtonian Slurries on Pump Performance
Performance for a 0.31 m diameter closed impeller pump while moving a tailings product, Solids concentration by volume of 47 and 49 % (Sellgren et al., 2011)
Slurry Test Schematic – GIW Hydraulic Lab
• 3 vane, 0.31 m Impeller Diameter• 0.1016 m suction• 0.0762 m line discharge• Diff. Pressure measured across
pump and 3 m horizontal section • Torque Bar• Tachometer• RTD Temperature read in tank• Magnetic Flow Meter• S.G. loop removed at high
yield stress values to reduce pipe friction higher % BEPQ
• Phosphate Clay, D93 = 20 um,D98 = 200 um
Tank Arrangement
Slurry Test Rig – GIW Hydraulic Lab
Results‐ Rheograms
3 ' 1 84 '
du n Vdy n D
Results‐ Pump Performance, varying Slurry
All Scaled to 1778 rpm
Results‐ Pump Performance, varying Speed
All Scaled to 1778 rpm, Slurry A
Results‐ Pump Performance, varying Speed and Slurry
All Scaled to 1778 rpm
Discussion/Analysis
( )1 y naµ k
2
Re impp
D
Solids Effects on Performance, HI Standard
Newtonian Viscosity Effects on Performance, HI Standard
Discussion/Analysis‐ Comparisons with Models
Head and Efficiency Derates Compared to Walker and Goulas, Slurry A, 50 % BEPQ
Discussion/Analysis‐ Comparisons with Models
• Sellgren and Addie (1990) looked at ways to find apparent viscosity from pump dimensions• Head and Efficiency Derates Compared to Graham et al. 2007:
42( )
imph
imp
w DD
D w
V 8V/D a H.I. 9.6.7-2010 HR, ER
Graham et al. method with w=0.25.Dimp= 0.078 m to the phosphate clay results here at 80 m3/hr HR = 0.85 and 0.82 for 1800 and 1450 rpm, respectively. The corresponding measured head ratios were 0.93 and 0.87, which would require w’ values of 0.041 m and 0.049 m in order to match the experimental head data. The actual width, w, for the pump used in the experiments is 0.028m.
Discussion/Analysis‐ Comparisons with Models
Head and Efficiency Derates Compared to Graham et al., w’=0.041, W&G, Slurry A
Conclusions• By removing entrained air using a modified tank, phosphate clay slurries with
Bingham yield stress values of 100‐600 Pa were able to be pumped.
• Derating in efficiency was generally larger than that for head.
• Deratings depended more strongly on the rotary speed than on the yield stress.
• Literature from loop tests with thickened tailings which are rheologically comparable may confirm an airlock effect during loop testing.
• Modeling approaches have been briefly discussed: Walker & Goulas, Graham et al.
• Future work• Thickened tailings two‐component behavior compared to clays calls for a
repeated test now with authentic tailings. • CFD modeling of transient full machine pumping a Bingham Plastic fluid.
Acknowledgements
Special thanks to John Tyler Leonard and Travis Basinger of GIW Industries for allof their work related to the experimental setup and data acquisition.
Questions
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Slurry Test Rig – GIW Hydraulic Lab
Cooling Troughs packed with ice
Slurry Pot/ Pressure TapsMagnetic Flow Meter