A

cross sectional area

C

absolute velocity

h

head loss

H

head

n

number of circulations (number of times the fluid passes through the impeller blades)

N

rotational speed (rpm)

p

pressure

K_p

is the loss coefficient related to the friction forces on the side channel wall

K_m

is the loss coefficient that takes into account all the losses due to enlargements or restrictions of the flow and to turbulence share forces in the vanes related to the circulatory flow rate.

Q

blower flow rate

r

radius

u

peripheral velocity

z

number of impeller blades

increase in pressure in the side channel

dimensionless flow coefficient

dimensionless head coefficient

density

efficiency

angular speed

blade angle (the theoretical angle of the flow)

flow angle (the actual angle of the flow)

slip factor

effective angle from the inlet to the outlet of the blower