How do you select and correct pump performance for viscous fluid handling?

Viscous fluids significantly reduce centrifugal pump performance compared to water. Hydraulic Institute method provides correction factors: C_Q (flow), C_H (head), C_η (efficiency) based on fluid viscosity and pump specific characteristics. High viscosity reduces efficiency more than head or flow. Effects: increased friction losses, reduced head coefficient, slip in clearances, higher power consumption. Selection approach: (1) Calculate required water-equivalent performance: Q_w = Q/C_Q, H_w = H/C_H. (2) Select pump for water duty. (3) Apply corrections to get viscous performance. (4) Verify NPSH_R increase (typically 1.5-2x for viscous fluids). For viscosity >500 cSt, consider positive displacement pumps. Temperature control may reduce viscosity during operation. Verify motor sizing for viscous power requirement at startup temperature (cold, high viscosity).