The following is a detailed explanation of the differences in shaft power calculation for three types of industrial pumps (centrifugal pumps, slurry pumps, and magnetic pumps), including specific formulas and correction factors:
1. Shaft power calculation for centrifugal pumps:
Basic formula:
P=Q×H×ρ×g/3600/η
Parameter description:
Q: flow rate (m³/h)
H: head (m)
ρ: medium density (kg/m³)
η: pump efficiency (usually 0.6~0.9)
Correction for particle-containing media:
When the medium contains solid particles (such as slurry, sewage), the wear coefficient (K) needs to be increased to compensate for impeller wear and decreased efficiency:
P correction=P×K (K=1.1~1.3)
Case:
Transporting sewage with 10% sand content (ρ=1100kg/m³, Q=100m/h, H=25m, η=0.7, K=1.2)
P=100×25×1100×9.81/3600/0.7×1.2≈15.3KW
2. Calculation of slurry pump shaft power:
Special formula:
N=H×Q×A×g/n/3600
Parameter description:
A: Slurry density (kg/m³), which needs to be obtained through actual measurement or calculation:
A=ρliquid×(1+Cv)
(Cv is the solid volume concentration, for example, when the solid content is 30%, Cv=0.3)
n: Pump efficiency (usually 0.4~0.6)
Case:
Transporting iron ore slurry
ρ liquid = 1200kg/m³, Cv = 0.25, Q = 80m³/h, H = 20m, n = 0.5)
A = 1200 × (1 + 0.25) = 1500kg/m³
N = 20 × 80 × 1500 × 9.81/3600/0.5 ≈ 26.2kW
3. Calculation of magnetic pump shaft power:
Correction formula:
P magnetic pump = P/η magnetic (η magnetic = 0.92 ~ 0.97)
Parameter description:
Magnetic transmission efficiency (usually 92% ~ 97%)
If calculated directly according to the centrifugal pump formula, an additional 3% ~ 8% power is required
Case:
Transporting hydrochloric acid (Q=30m³/h, H=15m, ρ=1259kg/m³, η=0.75, ηmagnetic=0.95):
Pbase=30×15×1250×9.81/3600/0.75≈3.1KW
Reasonable calculation of shaft power can improve the energy efficiency of the pump system by more than 20%. This article deeply analyzes the calculation method of industrial pump shaft power to help you achieve accurate selection and energy-saving optimization.