⚙️ Specific Speed & Specific Diameter (Cordier)
Compute Ns, Ds, Cordier diagram placement, and efficiency estimate for pumps, fans, and turbines.
📝 Configuration
📊 Results
Configure and click Compute.
📘 Methodology
Specific Speed
Ns = ω√Q/(gH)^0.75 is the dimensionless specific speed. It classifies machines: Ns < 0.2 → positive displacement, 0.2-1 → radial, 1-4 → mixed flow, > 4 → axial flow.
Specific Diameter
Ds = D·(gH)^0.25/√Q relates impeller size to operating conditions. The Cordier diagram plots Ds vs Ns and defines an optimal locus for each machine type.
Cordier Diagram
The Cordier line Ds = exp(1.25 − 0.40·ln Ns) predicts the optimal Ds for a given Ns. Deviation indicates suboptimal size. Peak efficiency typically occurs near the Cordier line.