Cordier Diagram

Christian Peter Kaiser

About this app

Cordier Diagram is a practical first-shot design tool for single-stage turbomachines — compressors, fans, pumps, water and gas turbines, and expanders.

WHAT YOU GET
• Separate Cordier optimum curves for turbines and compressors/pumps (σ–δ)
• Efficiency band around the midlines (in / above / below)
• Solve for diameter, volume flow, speed or specific work Y
• Gas: Y in kJ/kg · Liquid: Y, head H [m] or Δp [bar] (water, ρ ≈ 1000 kg/m³)
• Dimensionless numbers σ, δ, ψ, φ with range hints
• Impeller type suggestion: axial, diagonal or radial
• Interactive Cordier diagram (log–log) with operating point
• Logarithmic sliders, light & dark theme, English and German UI

HOW IT WORKS
1. Choose turbine/expander or compressor/fan/pump
2. Choose gas or liquid (for liquid: H, Δp or Y)
3. Set three of: volume flow, specific work, speed, diameter
4. Tap the calculator icon on the free variable to solve for it
5. Check badges, rings and the Cordier plot before detailed design

UNITS
• Volume flow: m³/s
• Specific work Y: kJ/kg (or H in m / Δp in bar for liquid)
• Speed: 1/min · Diameter: mm

IMPORTANT
This app provides a preliminary estimate only. It does not replace detailed design, standards or your engineering judgement. Always verify critical results before building or ordering hardware.

What’s new

Cordier Diagram 2.2 — modern release
• Material 3 UI, dark mode, DE/EN
• Gas/liquid: Y, head H or Δp (water)
• Cordier efficiency band + colour badges
• Log sliders, stable extreme ranges
• Formulas & notes in Help