Centrifugal Pump Hydraulics Calculator

A comprehensive tool for sizing pumps and analyzing hydraulic systems.

System & Fluid Properties

Suction Side Configuration

Suction Piping Segments

Suction Minor Losses

Discharge Side Configuration

Discharge Piping Segments

Discharge Minor Losses

Maximum Suction Conditions (for Shutoff Calc)

Head Calculation Breakdown

Total Static Head:-
Total Suction Loss:-
Total Discharge Loss:-
Total Dynamic Head (TDH):-

Pipe Sizing Analysis

Recommended Suction Size:-
Max Suction Velocity:-
Recommended Discharge Size:-
Max Discharge Velocity:-

NPSH Analysis

NPSH Available (NPSHa):-
NPSH Margin Status:-

Power Calculation

Brake Power (at Shaft):-
Required Motor Power (Est.):-
Est. Efficiency (Corrected):-

Shut-off Pressure & MCF

Max Discharge Pressure @ Shutoff:-
Pump Stability at MCSF:-

Actions

Technical Notes

Variable Definitions

  • Q: Design flow rate through the system (user input). Units per selected system.
  • SG: Specific gravity at pumping temperature (dimensionless). Used to estimate density for head/power.
  • ΞΌ: Dynamic viscosity (cP). Used for Reynolds number and friction factor selection.
  • Psrc: Source vessel operating pressure (gauge). Use 0 for open tanks.
  • Zsrc: Suction liquid level relative to pump centerline (positive if liquid above).
  • Pdst: Destination required pressure (gauge).
  • Zdst: Discharge elevation relative to pump centerline.
  • Pvap: Vapor pressure at pumping temperature (absolute). Used for NPSH.
  • TDH: Total Dynamic Head (m or ft) = static head + suction losses + discharge losses.
  • NPSHa: NPSH Available (m or ft) calculated at pump suction.
  • Ξ”Pmisc: Any known differential pressure drop not represented by segments/fittings (e.g., exchanger, filter).

Formulas / Logic

  • Continuity: Q converted to mΒ³/s for calculations: QmΒ³/s = QmΒ³/h / 3600.
  • Velocity: v = Q / A, where A = Ο€DΒ²/4 (internal diameter based on selected pipe size & schedule).
  • Reynolds number: Re = ρvD/ΞΌ.
  • Darcy–Weisbach friction loss: hf = f (L/D) (vΒ²/2g).
  • Friction factor: Laminar: f = 64/Re. Turbulent: Swamee–Jain explicit approximation to Colebrook: f = 0.25 / [log10(Ξ΅/(3.7D) + 5.74/Re0.9)]Β².
  • Minor losses: hm = K (vΒ²/2g) summed per side (fittings K-values are typical/indicative).
  • Static head: Hstatic = (Zdst βˆ’ Zsrc) + (Pdst βˆ’ Psrc)/(ρg).
  • Total Dynamic Head: TDH = Hstatic + hloss,suction + hloss,discharge.
  • NPSHa: NPSHa = (Patm + Psrc βˆ’ Pvap)/(ρg) + Zsrc βˆ’ hloss,suction.
  • Hydraulic power: Phyd = ρgQΒ·TDH. Brake power = Phyd/Ξ·. Motor power includes a simple drive factor.

Assumptions / Notes

  • Pipe data: Nominal sizes/schedules and roughness are indicative. Confirm against project piping spec and the applicable ASME B36.10M/B36.19M pipe dimensions.
  • Minor-loss K values: Typical values are provided for quick estimation; refine using a reputable loss-coefficient source (e.g., Crane TP-410) and actual fitting details.
  • NPSHr: This tool estimates NPSHr using an empirical correlation for screening only. Final NPSH margin must be confirmed from vendor pump curves (per API 610 / Hydraulic Institute guidance).
  • Shutoff pressure: Shutoff head is assumed as 125% of TDH for a conservative check. Actual shutoff head depends on the selected pump curve.
  • Viscosity correction: A simplified efficiency correction is applied for viscous liquids; for high viscosity or non-Newtonian fluids, use vendor curves or Hydraulic Institute method.
  • Units: Vessel pressures are treated as gauge inputs; vapor pressure is treated as absolute. Ensure consistency with your datasheets and operating basis.
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