α

Angle of absolute flow

β

Angle of relative flow

γ

slip coefficient, Stagger angle

δ

Deviation angle flow / blade

δr

Swirl number

ε

Drag ratio

η

Efficiency

μ

Decreased power factor (sweeping)

ν

Diameter ratio

π

Pressure ratio

ρ

Density

σ

Thickness in circumferential direction; Speed coefficient

τ

Blockage of flow channel by blades

φ

Wrap angle; Flow coefficient

ψ

Work coefficient (= pressure and head coefficient)

ω

Angular velocity

Λ,σ,δ,ν

Sweep angles

Symbol

Description

A

Cross section area

b

Width

c

Absolute velocity

cm

Meridional velocity (cm=wm)

cu

Circumferential component of absolute velocity

cL

Lift coefficient

cD

Drag coefficient

d

Diameter

f

Camber

F

Force

h

Enthalpy

H

Pump head

i

Incidence angle

l

Chord length

L

Length

M

Torque; Meridional coordinate

m

Meridional coordinate (dimensionless)

ṁ

Mass flow

n

Number of revolutions

nq, Ns

Specific speed

p

Pressure

P

Power

Q

Flow rate

r, R

Radius

s

Entropy, Orthogonal thickness

S

Static moment

t

Pitch; Tangential coordinate (dimensionless)

T

Temperature, Tangential coordinate

u

Circumferential velocity (Rotational speed)

v

Velocity

w

Relative velocity

wu

Circumferential component of relative velocity (wu+cu=u)

Y

Specific energy

z

Geodetic height; Number of blades