Reaction turbines

Question 1

how do reaction and impulse turbines differ in instigating the runner’s rotation

Answer 1

Impulse only uses the fluid velocity
Reaction utilizes both the pressure and velocity of the fluid

Question 2

Estimate the power extracted by
the turbine

Answer 2

= rho g H Q

head (H)
flow rate (Q)
density (rho)

Question 3

head loss along a pipe due to frictional losses

Answer 3

hl = hf
= 4f * LV^2 / 2gD

length (L)
frictional factor (4f)
velocity (V)
diameter (D)

Question 4

guide vane angle

Answer 4

the angle between U and V

blade speed (U)
fluid velocity (V)

Question 5

blade inlet angle

Answer 5

the angle between U and W

blade speed (U)
relative velocity (W)

Question 6

dimensionless specific speed (Kn)

Answer 6

= n sqrt(P) / sqrt(rho) (gH)^5/4

rotational speed (n)
power transferred (P)
effective head (H)

Question 7

work done per unit mass

Answer 7

= Vtheta1 U1 - Vtheta2 U2
= 1/2 (U1^2 -U2^2 + V1^2-V2^2 + W1^2-W2^2)

blade speed (U)
relative velocity (W)
fluid velocity (V)
inlet (1)
outlet(2)

Question 8

hydraulic efficiency

Answer 8

= Vtheta1 U1 - Vtheta2 U2 / gH