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Pump Calculator

Centrifugal & Positive Displacement Pumps

Single and multi-stage pump power, head, efficiency, NPSH and specific speed. Supports series (head addition) and parallel (flow addition) multi-stage configurations.

CENTRIFUGALPD PUMP MULTI-STAGE SERIESNPSH CHECK SPECIFIC SPEEDVISCOSITY CORRECTION

Stage(s)

—

kW Shaft

⚙️Pump Configuration

Type & Stages

Pump Type

Number of Stages

Stage Configuration

Process Conditions

Flow Rate Q (per stage)

m³/h

Total Head H (per stage)

Fluid Density ρ

kg/m³

Kinematic Viscosity ν

cSt

Water=1 cSt. If ν>10 cSt, efficiency correction (HI 9.6.7) applied to η_h.

Efficiencies

Pump Hydraulic Efficiency η_h

Mechanical Efficiency η_mec

Motor Efficiency η_motor

Shaft Speed N

rpm

NPSH & Suction Conditions — P_s and P_v must be ABSOLUTE pressures

Suction Pressure P_s

bar a

Absolute pressure at pump suction flange (gauge + atm)

Fluid Vapour Pressure P_v

bar a

⚠ Must be ABSOLUTE. Water@20°C ≈ 0.023 bar a

Suction Pipe Velocity V_s

m/s

Suction Head Loss h_fs

Static Elevation z_s (sump to pump)

Positive = pump above sump (reduces NPSHa).

NPSH Required (from vendor datasheet)

📊Calculation Results

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Awaiting Calculation

Enter pump parameters and click Calculate.

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Compressor Calculator

Multi-Stage Compressor with Intercoolers

Isentropic and polytropic analysis for each compression stage with inter-stage coolers. Stage-by-stage temperature, pressure and power breakdown.

ISENTROPICPOLYTROPICINTERCOOLERSTAGE POWER25+ GASES

Stage(s)

—

kW Shaft

⚙️Compressor Configuration

Type & Efficiency Mode

Compressor Type

Efficiency Basis

Gas Properties

Gas / Medium

Ratio of Specific Heats γ

—

Molar Mass M

g/mol

Cp Override (optional — overrides ideal-gas Cp)

J/(kg·K)

NH₃ ≈ 2170, CO₂ ≈ 850, propane ≈ 1670 J/(kg·K) at inlet conditions.

Inlet Conditions

Inlet Temperature T₁

°C

Inlet Pressure P₁

bar a

Actual Volume Flow Q (at inlet)

m³/h

Final Discharge Pressure P_out

bar a

Stages & Efficiencies

Number of Stages

Stage Ratio Mode

Stage Efficiency η

Mechanical Efficiency η_mec

Driver / Motor Efficiency η_drv

Intercooler Settings

💡 Intercooler cools gas back toward suction temperature — reduces next-stage compression work.

📊Stage-by-Stage Results

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Awaiting Calculation

Configure stages, gas, intercoolers and efficiency.

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Fan & Blower Calculator

Fans, Blowers & Axial Flow Units

Static, dynamic and total pressure rise — air power, shaft power, fan laws (affinity laws). Suitable for centrifugal fans, axial fans, blowers and ventilation units.

CENTRIFUGAL FANAXIAL FANFAN LAWSSTATIC EFFICIENCYSPECIFIC SPEED

—

kW Shaft

—

% η Total

🌀Fan / Blower Parameters

Type

Fan / Blower Type

Process Conditions

Volume Flow Q

m³/h

Static Pressure Rise ΔPs

Dynamic Pressure Rise ΔPd

Gas / Air Density ρ

kg/m³

Fan Speed N

rpm

Impeller Diameter D

Efficiencies

Total Fan Efficiency η_t

Motor Efficiency η_m

Fan Laws — Speed & Diameter Change Prediction

New Speed N₂

rpm

New Diameter D₂

📊Fan Results

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Awaiting Calculation

Enter fan parameters and click Calculate.

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Reference

Terms, Formulae & Definitions

Complete reference for pump, compressor, fan and blower engineering calculations — symbols, equations and design guidance.

💧Pump Formulae

Hydraulic Power:
P_hyd = ρ · g · Q · H / 1000 [kW]

Shaft Power:
P_shaft = P_hyd / (η_h · η_mec) [kW]

Input Power:
P_input = P_shaft / η_motor [kW]

NPSH Available (ISO 9906):
NPSHa = (P_s − P_v)·10⁵/(ρg) + V_s²/2g − h_fs − z_s

Specific Speed (SI, N_rpm basis):
Ns = N · √Q / H^(3/4) [Q m³/s, H m]
Radial: Ns <25 | Mixed: 25–120 | Axial: >120

Viscosity Correction (HI 9.6.7):
C_η ≈ 1 − 0.0105·(ν−1)^0.60 [valid 1–3000 cSt]

Q — Flow Rate: Volumetric flow m³/h or m³/s. For series stages: same Q per stage, head adds. For parallel: Q adds, same head.
η_h — Pump Hydraulic Efficiency: Ratio of fluid power to impeller mechanical input. Typical: 60–90% centrifugal, 75–92% PD.
NPSHa — NPSH Available: Suction energy margin above vapour pressure. Must exceed NPSHr + 0.5 m (HI safety margin).
Ns — Specific Speed (SI): Shape number defining impeller geometry. Evaluated at BEP. Low Ns = radial; high Ns = axial flow.

⚙️Compressor Formulae

Isentropic Discharge Temp:
T₂_is = T₁ · r^((γ−1)/γ) [K]

Actual T (isentropic eff.):
T₂_act = T₁ + (T₂_is − T₁) / η_is

Actual T (polytropic eff.):
n = γ / [γ − η_p·(γ−1)]
T₂_act = T₁ · r^((n−1)/n)

Shaft Power (all stages):
P_shaft = ΣP_act_stages / η_mec

Inlet Density (ideal gas, Z=1):
ρ₁ = P₁·10⁵·M / (R_univ·T₁)

γ — Ratio of Specific Heats: Air: 1.4, NH₃: 1.31, CO₂: 1.29. Controls temperature rise and compression work per stage.
η_is — Isentropic Efficiency: Actual vs ideal power ratio. Centrifugal: 70–83%; Reciprocating: 75–88%; Screw: 65–80%.
η_p — Polytropic Efficiency: Stage efficiency independent of pressure ratio, preferred for multi-stage design.
Intercooler: Cools gas back toward inlet T between stages, reducing next-stage compression work.

🌀Fan & Blower Formulae

Total Pressure:
ΔP_t = ΔP_static + ΔP_dynamic [Pa]

Air / Fluid Power:
P_air = Q · ΔP_t / 1000 [kW, Q in m³/s]

Shaft Power:
P_shaft = P_air / η_total [kW]

Static Efficiency:
η_s = Q · ΔP_s / (P_shaft · 1000)

Fan Laws:
Q₂ = Q₁·(N₂/N₁)·(D₂/D₁)³
ΔP₂= ΔP₁·(N₂/N₁)²·(D₂/D₁)²
P₂ = P₁·(N₂/N₁)³·(D₂/D₁)⁵

η_total — Total Efficiency: Ratio of total air power to shaft power. Typical: 60–85% centrifugal, 70–88% axial.
η_static — Static Efficiency: Preferred for open-outlet fans where dynamic pressure is not recovered.
Fan Laws: Affinity laws: Q∝N, ΔP∝N², P∝N³ (cube law) for same density. Valid near design point only.