4. Cascade Aerodynamics Flashcards
1
Q
what are the 3 sources of irreversibility when flow passes through a blade passage
A
- boundary layers on the blades
- flow separation
- shock waves in the flow
2
Q
what is camber θ
A
- θ = X1 - X2 for compressors
- θ = X2 - X1 for turbines
- X1 = inlet metal angle
X2 = exit metal angle
3
Q
what is pitch to cord ratio
A
- pitch to cord ratio = s/c
4
Q
what is axial velocity density ratio AVDR
A
- AVDR = ρ2Vx2 / ρ1Vx1 = h1 / h2
5
Q
what is the expression for the conservation of mass flow rate 𝑚̇ through a blade passage from V1 to V2 with angles α1 and α2 and a projected frontal area of hs
A
- 𝑚̇ = ρ2V2h2scos(α2) = ρ1V1h1scos(α1) = ρhs*Vx
6
Q
what is the general stagnation pressure loss coefficient Yp
A
- Yp = loss of stagnation pressure / reference dynamic pressure
7
Q
what is Yp for a compressor
A
- Yp = p01 - p02 / p01 - p1
8
Q
what is Yp for a turbine
A
- Yp = p01 - p02 / p01 - p2
