## 6.12. Notation

Symbol | Meaning | SI units | Imperial Units
C | Absolute velocity | m/s | ft/s
D | Diameter | m | ft
H0 | Stagnation enthalpy | J/kg | Btu/lbm
m | Mass flow | kg/s | lbm/s
mch | Mass flow at inducer choke | kg/s | lbm/s
mch a | Mass flow at inlet annulus choke | kg/s | lbm/s
M | Mach number | — | —
N | Rotational speed | rev/s | rev/s
P0 | Total pressure | Pa | lbf/in^2
qu | Quality | — | —
s | Entropy | J/kg-K | Btu/lbm-R
T0 | Total temperature | K | F
U | Blade speed | m/s | ft/s
V | Volume flow | m3/s | ft3/s
W | Relative velocity | m/s | ft/s
α | Absolute gas angle | m/s | ft/s
ß | Relative gas angle | deg | deg
ß' | Blade angle | deg | deg
ΔH | Increase in stagnation enthalpy | J/kg | Btu/lbm
Ω | Angular velocity | s^-1 | s^-1
ΔH/U2 5 | Work factor | — | —
NsND | Specific speed: | — | —
| Flow coefficient: | — | —
MU5 | Tip speed Mach number: | — | —
Suffixes |  |  |
1 | flowfield inlet |  |
2 | IGV exit |  |
3 | impeller inlet |  |
5 | impeller exit |  |
7 | compressor delivery |  |
hub | at inducer hub |  |
is | isentropic |  |
m | meridional direction or component |  |
shr | at inducer shroud |  |
w | tangential direction or component |  |
rms | root-mean-square inlet radius |  |

NB — the units listed above are those that are consistent with the dimensionless group definitions (NsND, etc). The definitions used in the Vista CCD GUI are listed in Viewing the Results.

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