Performance and Internal Flow Characteristics of a Very Low Specific Speed Centrifugal Pump

Schematic view of test pump 1 and tip clearance c

Test pump 2 and PIV measurement system

Test impellers for test pump 1

Test impellers for test pump 2

Performance curves of test pump 1 with change of tip clearance ratio (uncertainty of ϕ=±1.39%, of ψ=±1.0%, of ν=±1.49%, of η=±2.29%, of nsl=±1.15%)

Effect of tip clearance ratio on efficiency (uncertainty of ηmax=±2.29%, of ηD.P.=±2.29%)

Performance curves of test pump 2 (impellers D(β2=90deg) and E(β2=30deg)) (uncertainty of ϕ=±1.41%, of ψ=±2.16%, of ν=±1.5%, of η=±3.18%, of nsl=±2.21%)

Absolute tangential velocity at impeller outlet (uncertainty of υθ∕rω=±2.35%)

Change of slip factor by tip clearance ratio (Q∕Qd=1.0) (uncertainty of k=±2.35%)

Phase averaged velocity vectors of test pump 2 (uncertainty of vθ∕u2=±3.75%, of vr∕u2=±3.75%). (a) Impeller D (Q∕Q0=1.0, PTV). (b) Impeller E (Q∕Q0=1.0, PTV). (c) Impeller D (Q∕Q0=0.25, PTV).

Phase-averaged relative velocity vectors (impeller D, Q∕Q0=1.0, area 3, PIV) (uncertainty of vθ∕u2=±3.5%, of vr∕u2=±3.5%). (a) Plane 1 (z∕b=0.05). (b) Plane 2 (z∕b=0.5). (c) Plane 3 (z∕b=0.95).

Absolute tangential velocity ratio (impeller D, Q∕Q0=1.0, c∕b2=0.125, PIV) (uncertainty of vθ∕rω=±3.5%)

Change of absolute tangential velocity ratio by blade outlet angle (Impellers D and E, Q∕Q0=1.0, PIV) (uncertainty of vθ∕rω=±3.5%)

Change of absolute tangential velocity ratio by tip clearance ratio (impellers B′ and C′, Q∕Q0=1.0) (uncertainty of vθ∕rω=±0.75% and ±2.35% static pressure and LDV, respectively)

Change of absolute tangential velocity ratio by specific speed variation (Q∕Q0=1.0)