Nomenclature
c absolute velocity
Di impeller inner diameter
Do impeller outer diameter
q dynamic pressure based on impeller tip speed
Q volumetric flow rate
J advance ratio
FB blade body force
Fv viscous body force
p static pressure
Pt total pressure
P
t rotary stagnation pressure
Ri impeller inner radius
Ro impeller outer radius
rpm revolution per minute
S arc length measured around impeller
Tt total temperature
Ui blade speed at impeller inner radius
Uo blade speed at impeller outer radius
Uj propulsor exhaust velocity
Uw wake velocity
UN free-stream velocity
w relative velocity
Ws impeller shaft power
a absolute flow angle
b relative flow angle
b0 blade metal angle
z blade stagger angle
D overall change
e flow deflection (turning) angle
f fan flow coefficient
l power coefficient
O impeller rotational speed
Zc fan adiabatic compression efficiency
Zd diffuser efficiency
Zp propulsion efficiency
Zs fan total-to-static efficiency
Zt fan total efficiency
r density
c pressure coefficient
Subscripts
1 impeller first stage inlet station
2 impeller first stage outlet station
3 impeller second stage inlet station
4 impeller second stage outlet station
A region A
atm ambient condition
B region B
C region C
i inner blade station, also ideal
o outer blade station
r radial direction
s static
t total
v vortex (region C)
y circumferential direction
Others
e^r unit vector in radial direction
e^y unit vector in circumferential direction
n^ unit vector normal to mean streamline in impeller
region
o˜ total pressure loss coefficient