Separate the frames
Absolute velocity C belongs to the stationary frame. Relative velocity W is what a moving blade sees. Their difference is blade speed U.
04 / TRANSFER · Propulsion
Compressor Velocity Triangles
Cycle & componentsBrowser calculation
Unwrap a rotor at one radius. Change the swirl and see shaft work become total-temperature and pressure rise.
TURN THE FLOW. TRANSFER WORK.LIVE B
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Both velocity triangles use the same scale. C = W + U. Turquoise: absolute C; pink: relative W; amber: blade U. No blade shape, incidence, stall or surge prediction is made.
Remove swirl without adding work
The idealised stationary stator removes outlet swirl and raises static temperature. Total temperature remains unchanged through it.
Change efficiency independently
For a fixed velocity triangle, work and total-temperature rise stay fixed. Lower stage efficiency gives less total-pressure rise.
CALCULATED FROM THE SAME MODEL
Read the parameter study
B · solid turquoise A · dashed amber
Dots mark the selected settings; curves sweep one variable
Compare the evidence
| Quantity | A · saved | B · live | Unit |
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A remains fixed until you save again. Export includes settings, selected outputs and curve data.
Equations, assumptions and topic connections
Physical model
Steady mean-line constant-radius compressor energy account. Constant axial velocity, cp = 1005 J/(kg K), γ = 1.4, inlet total temperature 300 K. Rotor adds prescribed swirl; stator returns swirl to zero with unchanged total enthalpy. A selected overall stage efficiency determines total-pressure ratio. No radial equilibrium or compressor map is claimed.
Δht = U(Cθ₂ − Cθ₁); ΔTt = Δht/cp; PR = [1 + η Δht/(cpTt₁)]^(γ/(γ−1)). T = Tt − C²/(2cp). At 10 kg/s and mean radius 0.25 m, torque = ṁrΔCθ and shaft power = torque × U/r.
Topic connections
S10 · Subsystems 02, PDF pp. 15–26; candidate diagrams pp. 18–24. This connects velocity triangles to compressor work and cycle analysis. Original vector diagrams.
MIT · energy exchange with moving blades
Original schematic diagrams. No manufacturer performance, certification or maintenance-authorisation claim. Numerical verification checks the declared model; it is not experimental validation. Model version: course-foundations-v1.