Calculation
Hman = Hgeo + Δp/(ρ·g) + Hv
Besides the plain height difference, the pump must also overcome any pressure difference between source and destination vessel and all flow losses.
Dubbel Strömungsmaschinen R 3.3.2, Gl. (6) Anlagenförderhöhe HA = zII−zI + (pII−pI)/(ρg) + (vII²−vI²)/(2g) + HJ; hier ohne Geschwindigkeitshöhenterm
Manometric total head of a pump system
Besides the plain height difference, the pump must also overcome any pressure difference between source and destination vessel and all flow losses.
MINTSI
02
Result
Select a target and calculate.
Understand the inputs
- Manometric total head Hman — Total head the pump must deliver overall.
- Geodetic lift Hgeo — Height difference between the liquid level in the source and destination vessel.
- Pressure difference between vessels Δp — Difference between the pressures acting on the liquid surfaces, e.g. for a pressurised destination vessel.
- Fluid density ρ — Density of the pumped liquid.
- Gravitational acceleration g — Local gravitational acceleration, about 9.81 m/s² near sea level.
- Pipeline loss head Hv — Sum of all friction and minor loss heads in the suction and discharge piping.
Example
Hgeo=10 m, Δp=0.5 bar, ρ=1,000 kg/m³ and Hv=2 m give Hman=10+5.10+2≈17.10 m.
Assumptions and limits
Steady operation at constant flow rate; Hv must already come from a separate pipeline-loss calculation and is not determined here itself.
Understand Manometric total head of a pump system
This calculator determines the total head a pump must actually deliver between two vessels, complementing the existing NPSH calculation (suction-side cavitation reserve) with the discharge side of the system.
What does this quantity describe?
Manometric total head has three components: geodetic lift Hgeo, any pressure difference between the vessels Δp/(ρg), and the sum of all pipeline losses Hv: Hman=Hgeo+Δp/(ρg)+Hv.
Formula and variables
Hman = Hgeo + Δp/(ρ·g) + Hv
Hman = Hgeo + Δp/(ρ·g) + Hv
| Symbol / input | Meaning |
|---|---|
| Manometric total head Hman | Total head the pump must deliver overall. |
| Geodetic lift Hgeo | Height difference between the liquid level in the source and destination vessel. |
| Pressure difference between vessels Δp | Difference between the pressures acting on the liquid surfaces, e.g. for a pressurised destination vessel. |
| Fluid density ρ | Density of the pumped liquid. |
| Gravitational acceleration g | Local gravitational acceleration, about 9.81 m/s² near sea level. |
| Pipeline loss head Hv | Sum of all friction and minor loss heads in the suction and discharge piping. |
Choose the inputs correctly
Hgeo is the height difference between liquid levels, Δp the pressure difference between the vessel interiors, ρ fluid density, g gravitational acceleration, and Hv the already-computed sum of pipeline losses.
How to use the calculator
Take Hgeo from the system drawing, Δp from vessel pressures (0 if both are open), and derive Hv from a separate pipeline-loss calculation (e.g. Darcy-Weisbach).
Worked example
Hgeo=10 m, Δp=0.5 bar, ρ=1,000 kg/m³ and Hv=2 m give Hman=10+5.10+2≈17.10 m.
Understand the result and units
The pump must deliver at least Hman at the required flow rate at its best-efficiency point; an undersized pump will not reach the required flow rate.
Hgeo, Hv and Hman are lengths (heads), Δp a pressure, ρ a density, g an acceleration.
Typical applications
Selecting a pump from its performance curve, a basis for determining specific speed, and plausibility-checking existing systems.
Assumptions, limits and common mistakes
Steady operation at constant flow rate; the velocity-head term (vII²−vI²)/(2g) of Dubbel Eq. (6) is dropped because still vessel surfaces are assumed. Hv must already come from a separate calculation. Start-up transients, pressure surges and time-varying vessel levels are excluded.
Common mistake: Do not forget Hv or confuse it with geodetic lift; omitting the loss head underestimates the pump power actually required.
Frequently asked questions
What is “Manometric total head of a pump system” used for?
Selecting a pump from its performance curve, a basis for determining specific speed, and plausibility-checking existing systems.
Where do the input values come from?
Hgeo is the height difference between liquid levels, Δp the pressure difference between the vessel interiors, ρ fluid density, g gravitational acceleration, and Hv the already-computed sum of pipeline losses.
What does the result not cover?
Steady operation at constant flow rate; the velocity-head term (vII²−vI²)/(2g) of Dubbel Eq. (6) is dropped because still vessel surfaces are assumed. Hv must already come from a separate calculation. Start-up transients, pressure surges and time-varying vessel levels are excluded.