NPSHa = P_suction*10.2 - H_vapour - H_suction_friction
=CEILING(P_m, 1.5) ' Rounds up to nearest 1.5 kW or 2 HP Create a clean Output section that automatically updates:
Q_m3h = 50 [m³/h] Q_m3s = Q_m3h / 3600 D_m = 0.08 [80 mm] Area = PI() * (D_m/2)^2 v = Q_m3s / Area f = 0.02 (assume clean steel pipe) L = 150 g = 9.81 H_friction = f * (L / D_m) * (v^2 / (2*g)) Create a lookup table for f based on pipe material and Reynolds number using the Moody chart. Use XLOOKUP or INDEX-MATCH . 2.3 NPSH Available (Net Positive Suction Head) – The Cavitation Check Cavitation destroys pumps. Always calculate NPSHa:
H_friction = f * (L / D) * (v² / (2*g))
| Parameter | Formula | Excel Example | | :--- | :--- | :--- | | Hydraulic Power (P_h) | Q (m³/s) * TDH (m) * ρ * g | = (Q_m3h/3600) * TDH * 1000 * 9.81 | | Shaft Power (P_s) | P_h / Pump Efficiency (η_p) | = P_h / 0.75 (for 75% efficiency) | | Motor Power (P_m) | P_s / Motor Efficiency (η_m) | = P_s / 0.92 |