246
6 Steam Turbines
c. Determine the rotor work and the internal efficiency. The height difference
between the outlet of the rotor and the downward water level is 0.20 m. The head
supplied to the machine is 3.00 m + 0.30 m + 0.20 m = 3.50 m.
d. Split the rotor work into the action and reaction parts. Determine the degree of
reaction. Observe that it is a low positive number.
e. Determine the speed ratio. Calculate the spouting velocity from the supplied
head of 3.50 m.
f. Make the balance of the rotor work, the losses in stator and rotor, the kinetic
energy at outlet and the downward head. The sum of the energy terms should
be equal to the supplied mechanical energy. Determine the fraction of the outlet
kinetic energy in the balance. Observe that outlet kinetic energy is the largest part
of the losses.
g. Determine the number of stator vanes and rotor blades from a Zweifel coefficient
value of 0.8.
1a
1u
v
3.575m / s,v
6.191m / s, u 3.213m / s, W 19.892J / kg ,
:
D
=
=
=
=
A
η
λ
i
R
=
=
=
0 579
0 0365
0 388
.
,
.
,
.
, outlet kinetic energy is 18.61 % of the supplied
mechanical energy, Z
Z
s
r
= =
23
50
,
.
References
1. Balje OE (1981) Turbomachines: a guide to design, selection and theory. Wiley, ISBN 0-47106036–4
2. Denton JD (1993) Loss mechanisms in turbomachines. J Turbomach 115:621–656
3. Dixon SL, Hall CA (2014) Fluid mechanics and thermodynamics of turbomachinery, 7th edn.
Elsevier, ISBN 978-0-12-415954–9
4. Korpela SA (2011) Principles of turbomachinery. Wiley, ISBN 978-0-470-53672–8
5. Lampart P, Hirt L (2012) Complex multidisciplinary optimization of turbine blading systems.
Arch Mech 64:153–175
6. Lewis RI (1996) Turbomachinery performance analysis. Wiley, ISBN 0-470-23596–9
7. Moustapha H, Zelesky M, Baines C, Japikse D (2003) Axial and radial turbines. Concepts
NREC, Wilder. ISBN 0-933283-12–0
8. Rosic B, Xu L (2012) Blade lean and shroud leakage flows in low aspect ratio turbines. J Turbomach 134:031003
6 Steam Turbines
c. Determine the rotor work and the internal efficiency. The height difference
between the outlet of the rotor and the downward water level is 0.20 m. The head
supplied to the machine is 3.00 m + 0.30 m + 0.20 m = 3.50 m.
d. Split the rotor work into the action and reaction parts. Determine the degree of
reaction. Observe that it is a low positive number.
e. Determine the speed ratio. Calculate the spouting velocity from the supplied
head of 3.50 m.
f. Make the balance of the rotor work, the losses in stator and rotor, the kinetic
energy at outlet and the downward head. The sum of the energy terms should
be equal to the supplied mechanical energy. Determine the fraction of the outlet
kinetic energy in the balance. Observe that outlet kinetic energy is the largest part
of the losses.
g. Determine the number of stator vanes and rotor blades from a Zweifel coefficient
value of 0.8.
1a
1u
v
3.575m / s,v
6.191m / s, u 3.213m / s, W 19.892J / kg ,
:
D
=
=
=
=
A
η
λ
i
R
=
=
=
0 579
0 0365
0 388
.
,
.
,
.
, outlet kinetic energy is 18.61 % of the supplied
mechanical energy, Z
Z
s
r
= =
23
50
,
.
References
1. Balje OE (1981) Turbomachines: a guide to design, selection and theory. Wiley, ISBN 0-47106036–4
2. Denton JD (1993) Loss mechanisms in turbomachines. J Turbomach 115:621–656
3. Dixon SL, Hall CA (2014) Fluid mechanics and thermodynamics of turbomachinery, 7th edn.
Elsevier, ISBN 978-0-12-415954–9
4. Korpela SA (2011) Principles of turbomachinery. Wiley, ISBN 978-0-470-53672–8
5. Lampart P, Hirt L (2012) Complex multidisciplinary optimization of turbine blading systems.
Arch Mech 64:153–175
6. Lewis RI (1996) Turbomachinery performance analysis. Wiley, ISBN 0-470-23596–9
7. Moustapha H, Zelesky M, Baines C, Japikse D (2003) Axial and radial turbines. Concepts
NREC, Wilder. ISBN 0-933283-12–0
8. Rosic B, Xu L (2012) Blade lean and shroud leakage flows in low aspect ratio turbines. J Turbomach 134:031003