Symbol

Definition

BPF

Blade passing frequency, Hz

c1

Fluid velocity at impeller inlet, m/s

c1\

Fluid velocity at impeller inlet corresponds to blade shift angle, m/s

c2

Fluid velocity at impeller outlet, m/s

cu2

Euler component of fluid velocity at impeller outlet, m/s

cm2

Flow component of fluid velocity at impeller outlet, m/s

cs

Fluid velocity at the pump suction, m/s

g

Gravitational acceleration, m/s2

H

Pump total head, m

Q

Pump discharge, l/h

N

Pump rotational speed, Hz, rpm.

NPSHA

Available net positive suction head, m

NPSHR

Required net positive suction head, m

ps

Absolute pressure in the pump suction, related to the pump centreline, Pa

Ps

Absolute pressure at the pump suction, bar

Pd

Absolute pressure at the pump discharge, bar

pv

Absolute vapour pressure at the fluid temperature, Pa

RF

Frequency corresponds to the pump rotational speed = N/60, rps or Hz

u1

Peripheral speed of impeller inlet, m/s

u2

Peripheral speed of impeller outlet, m/s

w1

Fluid velocity at impeller inlet relative to the impeller peripheral speed, m/s

w2

Fluid velocity at impeller outlet relative to the impeller peripheral speed, m/s

w1\

Fluid velocity at impeller inlet relative to the impeller peripheral speed corresponds to blade shift angle, m/s

z

Potential elevation, m

β1

Inlet blade angle, degree

β1\

Inlet blade angle at high flow rate, degree

Β2

Outlet blade angle, degree

Δβ1

Blade shift angle at blade entrance, degree

x

Cavitation strength, %

ρ

Density of fluid, kg/m3

s

Thoma cavitation number