Raabe J. Hydro power - the design, use, and function of hydromechanical, hydraulic, and electrical еquipment
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In decimal fractions, the decimal point is replaced by a comma, e.g.,
5,6
is used instead
of
the Anglo American 8
-
6.
In products, multiplication mark
'
x
'
is replaced by a point e.g.,
S
-
23 is used instead of
the Anglo American 8
x
23. The multiplication mark
'
x
'
is reserved for vector products
a
x
b,
b) multipliers that extend over one line, c) output of
3
equal sets thus
P
=
3
x
30
MW
occasionally used.
Abbreviations: Machines types are usually abbreviated as follows: Kaplan turbine
=
KT
(plural
KTs), Francis turbine
=
FT, Pelton (impulse) turbine
=
PT, pump-turbine
=
PUT, tubular turbine
=
TT, bulb turbine
=
BT, pump
=
P,
Straflo turbine
=
ST.
The vorticity rot
c
is denoted by curl
c.
The inverse functions of sin
x,
cos x, tan x, cotan
x
are denoted by arcsin
x,
arccos
.u,
arctan x, arccotan
x,
instead of sin-'x, cos-' x, tan-' x, cotan-'x.
How to use the references in the text: All references within the text are put in square
brackets and can be found in a reference list at the end of the last chapter. There they are
arranged by chapters and within the chapters in the sequence they are quoted in the
respective chapters. The first number points to the chapter, the second number to the
reference. For example
[9.18] quotes reference 18 in chapter 9. More references can be
quoted by
[9.18; 9.191, [9.18 to 9.301 or [8.5; 9.181. References which are not quoted in the
book are found in the second list of reference at the end of the book, arranged in
alphabetical order of the author's names. At its end, the latter is supplemented by same
references, that came out during the production of this book.
Equations are quoted by numbers put in round brackets and' placed behind the number
of the subchapter in which the equation appears,
e.g. (10.2-4) refers to equation 4 in
subchapter
10.2.
Hints at subchapters are quoted by cap, and the number of the subchapter behind it, e.g.
cap.
9.3.1 hints at subchaptcr 9.3.1.
The figures are numbered through consecutively, subchapter by subchapter, the number
of which precedes that of the figure,
e.g. Fig. 9.2.1 hints at figure
1
in the subchapter 9.2.
Contents
........................
Nomenclature
......
;
1
1
.
The origin
of
hydro power. its potential and its use in a world wide context
9
............................
1.1. Introduction
9
...............
1.2. Water from rivers. its causes and features
9
.........................
1.2.1. The rivers 9
................
1.2.1
.
1. Large sources of water power
9
......
1.1.2. Characteristics and classification of well-known rivers 10
..................
1.2.1.3. Depth and slope of a river 11
................
1.2.1.4. High head and large discharge 12
........................
1.2.2. Topography 12
................
1.2.2.1. The Elements of the continents 12
..............
1.2.2.2. Topography and water circulation 13
......
1.2.2.3. Topography as the origin of falls and water collection 13
..........................
1.2.3. Climate 14
...................
1.3 The potential and its distribution 14
..........
1.3.1. Theoretical, harnessable, harnessed, potential 14
.......
1.3.2. Distribution of harnessed and harnessable potential 17
...................
1.4. Hydroelectricity, its development
20
1.4.1. Past and future of hydro power in the context of other power
.
. 20
.........
1.4.2. Cost and social problems due to electrification 21
................
1.4.3. The Future of hydroelectricity 21
......
1.5. Hydro power, its actual dimensions, development and features
22
.....
1.5.1.
The largest structures found in hydro power at present
22
...............
1.5.2. Survey of historical development 24
..............
1.5.3. The Features of water power plants 25
................
1.6. Survey of types of hydro power plants 25
........
1.6.1. Plants of conversion of hydraulic primary energy 25
........
1.6.1.1. General remarks on conversion of primary energy 25
.....................
1.6.1.2. River power plants 26
...................
1.6.1.3. Depression power plants 27
........................
1.6.1.4. Wave energy 27
.....................
1.6.1.5. Tidal power plants 29
.............
1.6.1.6. Hydro power from gas washers
..
.'
31
..........
1.6.2. Plants for converserion of secondary energy 31
......
1.6.3. Hydro power in transmission drives (torque converter) 36
......
1.6.4. Hydro power plants with respect to their availability 37
.......
1.6.5. Hydromechanical equipment of outstanding plants
39
............................
2.1.
Introcluct~o~i
41
...............
2.2.
l;.cononiic.~l ii\pccts
of
hydro yoccr
pi,
~nts
42
2.2.1.
Gc~icriil
I.CIII;I~~
;iboilt fc;ihil~ility
of
ii
project
..........
42
.....................
2.2.2. Tlic clcc~ricity rate 42
..........
2.2.3. l'lic spcci tic invcstr-nent cost pcr inst:~llcct
k\I1
42
..............
2.2.4. Econoniic appruisi~l of the projects
46
..................
2.2.4.1. Tht: present \ri~luc nictl~od 46
................
2.2.4.2. i~iternal rate of return ~ncthod 47
....................
2.2.4.3. I'lieunni~ity method
47
....................
.
2.2.4.4. The bcncfit-cost ratio
45
.........
2.2.4.5. Pr~duction cost of energy iinit, electricity
raie
49
...........
2.3.
The
hydro po~ver cicvelopmt.rrt of some Iargc rivers
49
....................
2.3.1. The Tennessee
(USA)
39
................
2.3.2. The Columbia
(USA,
Carlacia) 49
...........
2.3.3. The
Far-~ini
(Brazil, Paragiiay,
Argentine)
53
................
3.4 The Yenissci
(USSR,
Siberia) 56
..............
2.3.5.
The
Volga
(USSR,
Eilropean part) 59
.........
2.3.6.
I'he
Zani besi (Zimbabwe, bloza~nbique, Africa)
59
........................
2.3.7.
TheDanube 61
..........................
2.4. Exceptional sltes 64
2.4.1.
Churchill 1-alls
(Chur-chill
River, Labrador, Canada)
......
64
..................
2.4.2.
Inga
(Znirz,
Co~go) Africa
06
.....................
2.5.
Srnal!
hydro powcr schemes 67
....
3
.
Sur\e:i
and
classificntion
of
essential
de\ices
of
a
hydro
powcr
plant
71
......................
3.1.
Ir;tr3duction
ant1
su;vcy 71
................................
3.2. Dams
74
....................
3.2.1. Classification
of
dams 74
.........
3.2.2.
The foundation of
a
dam
and
related problems 74
.......................
3.2.7. Gravity dams 75
........................
3.2.4. Arch da11is
77
.....................
3.2.5. Multiple arch dams
75
3.2.6.
Response of present society
to
social and ecological Impacts of dams
80
...........
3.2.7.
Environmental conseqilenccs of I;~rge dams
81
................
3.3. The spillway, sates and shut off devices 81
3.3.1. The
spili\vay in connection with other members of the plant
...
81
.........................
3.3.2. The spillway 85
..................
3.3.2.1.
The
dutie5 of the spillway
85
..............
3.3.2.2. Sur\ey of Food discharging devices 86
................
3.3.2.3.
Fiied
flood discharging devices 56
.......
3.3.2.4. Weir yiite; as an adjustable flood discharging
device
38
...............
3.3.2.5. Dynamic behaviour of spillways
91
......................
3.3.3. The stilling basin
92
..........................
3.3.4. V:~lves 92
.................
3.4.
The Po111er housc and its equiprient 94
...........
41
.
The
consti:uen! elernents ot' a power house
34
......................
3.4.1.1.
Gencral
remarks
94
............
3.4.1.2. The si~pcrstructure
of
the power
house
95
XVI
3.4.1.3.
The substructure of the power house
.............
129
3.4.2.
Power house design with respect to distance from dam
......
131
4
.
The layout of river-run and storage plants with respect to optimized figures sucli
as
rated discharge. nnmber of sets and their diameter. storage volume. hydraulic
......
radius of water way and dimensions of electric transmission line
135
............................
4.1.
Introduction
135
.........
4.2.
Optimization of rated discharge of a run-of-river plant
137
..............
4.2.1.
General remarks and assumptions
137
.................
4.2.2.
Specialization of the problem
139
.......
4.2.2.1.
The Case of given runner diameter
D
and desired
i
139
4.2.2.2.
The Case of given number
i
of sets and diameter
D
to be estimated
142
........
4.2.3.
Example of the estimation of runner diameter
D
142
.....
4.2.4.
Reasons for the number of sets relating to the turbines
143
4.3.
The optimum size
(D)
and number of sets for a river power plant with given
....................
rated discharge and rated head
144
.........
4.3.1.
Introduction to the problem and assumptions
144
.......
4.3.2.
The runner diameter as a function of working data
145
...................
4.3.2.1.
Kaplan turbines (KTs)
145
....................
4.3.2.2.
Francis turbines (FTs)
145
.....
4.3.3.
The runner diameter as a function of the number of sets
146
......
4.3.4.
The
NPSH
as function of the working data and type
146
......
4.3.5.
The cost of ground excavation, power house and dam
147
...........
4.3.6.
The cost of fabrication and erection of sets
148
.........
4.3.7.
The cash value of energy loss during useful life
148
.......
4.3.8.
The resulting cost as a function of number of sets
i
149
........
4.3.9.
Reasons for setting unit size as large as possible
149
.........
4.4.
The optimum coefficient of peripheral blade speed
Ku
150
.................
4.4.1.
Introduction to the problem
150
........................
4.4.2.
Assumptions
151
.........
4.4.3.
Expressing the cost terms as a function of
Ktr
152
......
4.4.4.
The resulting cost of the turbine during its useful life
152
..............
4.5.
Problems due to the layout of the reservoir
153
...........
.
4.5.1.
Basic considerations concerning a reservoir
153
........................
4.5.1.1.
Introduction
153
...........
4.5.1.2.
Assumptions for basic relations of layout
154
........
4.5.1.3.
The basic relation for the layout and its problems
154
.....
4.5.2.
An approach to the layout of a peak load storage plant
155
.........
4.5.2.1.
Basic relations of reservoir and river feeding it
155
........
4.5.2.2.
Load demand and its balance with energy stored
156
4.5.2.3.
Storage volume required, also for pumped storage
.......
156
...
4.5.2.4.
Economical aspects of the layout of a pumped storage plant
157
.......
4.6.
The problems of optimizing the cross section of water ways
158
......................
4.6.1.
General remarks
158
4.6.2.
The optimization of the channel section
............
159
4.6.2.1.
The rectangular channel section as a model and the resulting loss
.
159
................
4.6.2.2.
The cash value of energy loss
159
..............
4.6.2.3.
The investment cost of the channel
160
.........
4.6.2.4.
The resulting cost
and
the optimum depth
4,
160
XVII
.....
4.6.3.
'fhe
optimization of' the diameter of
a
prcsst~rizcd duct
161
........
4.6.3.1.
The
duct wilh cylindric;d cross section as
n
model
I61
............
4.6.3.2. Thc loss,
its
cash value;
investment
cost
161
...........
4.6.3.3. Thc
resulting
cost and optitnutn dinrncter
161
.........
4.7. Problems of optimization of electric power transmission
163
......................
4.7.1. Historicalsurvey
163
4.7.2. The cost of 1
%
loss in relation to that of power transn~ission . . 164
..............
4.7.3. The optilnization of the conductor 164
.......
4.7.4. The distance of adjacent towers and cable geometry 166
...........
4.7.5. The optimum distance of adjacent towers 167
....................
4.7.6. Future developments 165
....
5
.
Survey
of
basic
hydrodynamics. with
special
reference to hydro power
1'11
............................
5.1. Introduction 171
...................
5.2. The kinematics of an ideal flow 172
..............
5.2.1. Mass conserversation (Continuity) 172
.............
5.2.2. Potential flow and the curl (vorticity) 173
.......
5.2.3. The potential flow in the meridian. stream function I74
..............
5.2.4. Velocity triangle and relative eddy 175
...................
5.2.5. The rate of strain tensor 177
.............
5.2.6. The circulation and its relation to curl 178
...................
5.2.7. Vane circulation and lift 179
.......................
5.3. Dynamics of ideal flow 180
5.3.1. Equation of motion and energy for a stationary frame of reference
180
5.3.2.
Equation of motion and energy for a rotating frame of reference
182
.........
5.3.3. The role of unsteadiness for energy transmission 183
..................
5.3.4. The momentum theorems 183
......
5.3.5. Problems using the momentum and energy theorems 154
......................
5.3.5.1. Euler's equation 184
.........
5.3.5.2. The shock loss due to diffusion and deflection 185
.......
5.3.5.3.
The shock loss due to the action of turbo machines 186
......................
5.4.
Theory of real fluid flow 188
...................
5.4.1. Properties of real liquids 188
......................
5.4.2. 'The stress tensor 189
...........
5.4.3. The relation between stress and strain rate 190
.................
5.4.4. The Navier Stokes equation 190
...................
5.4.5. Boundary layer theory 191
....................
5.4.6. Flow in straight pipes 191
.............
5.4.6.1.
General phenomena and laminar flow
19;
................
5.4.6.2. Turbulent flow and transition 193
........
5.5. Loss mechanism due to real flow in hydro turbomachines 195
.....
5.5.1.
Some general remarks on loss in hydro turbo machinery 195
...........
5.5.2. Some loss mechanism of general character 195
.......
5.5.3. Interaction of main flow and boundary layer, stall 196
............
5.5.4. Diffuser (draft
tube)
flow, rotating stall 196
..........
.
5.5.5. Secondary flow in curved and rotating ducts 197
......
5.5.5.1. Due to turbulence, consequence on energy conversion 197
........
5.5.5.2. Interaction of bou~~dary layer and the main flow 199
............
5.5.5.3. Secondary flow in axial turbomachines
201
5.5.5.4. Secondary
flow
due to relative whirl in an axial turbomachine
.
.
201
.......
5.5.6. The predicition of component loss in fluid machines 202
.........
5.5.6.1. The rotor vane loss by means of aerodynamics 202
.................
5.5.6.2. The draft tube (diffuser) loss 203
......................
5.5.6.3. Disk friction loss 204
.................
5.5.6.4. The leakage (volumetric) loss
205
............
5.5.6.5. The windage loss of an impulse turbine
207
.........
5.5.6.6. The loss due to cross flow on a bucket of a PT
208
.............
6
.
Prediction of internal
flow
in cascades and rotor
209
............................
6.1. Introduction 209
.........
6.2. The straight cascade as
a
model for axial fluid machines
209
6.2.1. Prediction of flow (indirect problem) by means of singularities
.
.
209
........
6.2.1.1. Introduction. description and theory of problem 209
...........
6.2.1.2. Practical solution of the indirect problem 213
.......
6.2.1.3. Simplified method after Ackermann and Birnbaum
213
............
6.3. Some problems of steady flow through cascades 219
.....
6.3.1. The circular cascade with axisyminetric stream surfaces 219
.........
6.3.2.
The direct problem of a cascade in potential flow 220
6.3.3.
The indirect problem of the flow through a mixed flow rotor on
..........
axisymmetric stream faces of constant depth
221
....
6.3.4.
Cascade in an axisymmetric flow lamina of variable depth 223
6.4. The unsteady flow through straight cascades in tandem arrangement, moving
........................
relative to each other 226
........................
6.4.1. Introduction 226
..............
6.4.2. Model of cascade and assumptions 226
.................
6.4.3. Basic idea of the procedure 227
.................
6.4.4. Realization of the procedure 228
....................
6.4.5. List of used symbols 229
........
6.4.6. Derivation of governing linear integral equation 229
6.4.7.
Solution of integral equation by polynomials following
M
.
Lotz . .
230
............
6.4.8. Lift and moment on the passive cascade 231
................
6.4.9. Discussions of evaluated results 231
.........
6.4.10. Conclusion of practical results, effect of wakes 232
........
6.5. Distribution of meridional velocity normal to stream face 234
........................
6.5.1. Introduction 234
.....................
6.5.2. Special assumptions 235
......
6.5.3. Equation of motion, Euler's relation, loss formulation 235
.........
6.5.4.
ci
as a function of moment of momentum
c,
r
236
.......
6.5.5. Linear differential equation for the
c,
distribution 237
............
6.5.6. Step
by
step solution for the design task 237
6.5.7.
Calculating
c,
(n)
or
y(x)
for a runner of given geometry under
a
......................
given flow rate
Q
237
........
6.5.8. Computation of
fl
as function of vane geometry 238
................
6.6. The slip effect in the flow past a rotor
238
........................
6.6.1. Irltroduction 238
...........
6.6.2. Slip
p;t,
in coilsequence of the relative eddy 240
...............
6.6.3. Slip
p:
in consequence of wakes 240
XIX
............
6.6.4. Slip/).;
ninconsctlucnccofcasc.rclcHow
341
....
6.6.5.
Slip
pz
as
;i
consequence
of varying ~hc breath of thc rotor
24;
7
.
Losscs
tluc
ro
vorticity
nntl
boundary
layers
...............
345
............................
7.1. Introduction 245
........
7.2. I3robletns cluc to kinematics of vortices
in
fluid machines
245
..................
7.2.1. Fund~in~cntals of vortices 245
.........
7.2.2. Energy loss due to lengthening of vortcx tube 246
.....
7.2.2.1. Lengthening of
a
vortex tube prirnllc! to the n~r~in
tlow
246
......
7.2.2.2. Dislocation and Icnzthening of
a
vortcx within
2
bend
247
.........
7.2.2.3. Tllc lcngtl~cning of
a
vortex tubc within
a
rotor
248
..........
7.2.2.4.
Generation
of secondary flow past a cascade
2.19
.......
7.2.2.5. The s~reamwise vorticity pasi
i~
radial flow impellcr 250
.........
7.3. The boundarv layer and its dissipation at the rotor wall
251
........................
7.3.1. Introduction 251
........................
7.3.2. Assumptions 251
7.3.3.
The momentum
theorem of
a
boundr~ry layer on
a
c~~rved rotor vane
255
....
7.3.4. Differential equation for the growth of the boundary layer
257
..........
7.3.5. Con~putation of the wake past
a
rotor vane 260
7.3.6. The energy theorem of the boundary layer and ioss predictions
.
.
263
................
7.3.7.
I'he
flow about the inlet edge 267
...........
8
.
Cavitation
and
water
hammer
as detriniental effects 270
............................
8.1. Introd~~crion 270
.............................
8.2. Caviiatioii 271
....
8.2.1. Survey of fundamentals of cavitation and res~~lting erosion 271
.......
8.2.1.1. In!roduction to the \larious phenomena and aspects 271
......................
8.2.1.3. Piuclci as origin 272
.......
8.2.1.3.
Ilquatior? of motion of a bubble restings in the lluid
274
.......
8.2.1.3. Some estimates on cavitation scale effects at onset 275
..............
8.2.1.5. Transfer
ot'
energy under cavitation 276
................
5.2.1
6
.
Gas
diffusion
u~dcr cavitation 276
.......
8.2.i.7. Uubb!e collapse, impact pressure and related ctTects 277
...........
S.S. C;tvitation erosion, cause, devices, results 277
........
8.2.2. Ca~.itation with respect to hydro turbomachinery 280
.........
8.2.2.1. Suction head required, cavitation indices used 280
...............
8.2.2.2. The meaning of cavitatiorl index
253
...........
8.2.2.3. Theoretical cavitation index, scale effects 284
............
8.2.2.4. Influence of air content and its control 254
............
8.2.2.5. The influence of roughness on cavitation 285
........
5.2.2.6. Differences in cavitation
of
turbines and pumps 287
......
5.2.2.7. Cavitation
in
pumps or pump-turbines when pumping
355
....................
5.2.2.5. Cavitation in turbines 290
.............
5.3.2.9
Protective
measures against cavitation 293
8.2.3.
An
approach for the prediction of pressure number at the ciritical
................
.....
point in the rotor
:
295
........................
8.2.3.1. Introduction 295
........................
5.2.3.2. Assumptions 296
....................
8.2.3.3. Mised flow rnacllines 236
........................
8.2.3.4. Axial machines 299
.......
8.2.4. Fundamentals of pitting rate as function of velocity 302
........................
8.2.4.1. Introduction 302
.....
8.2.4.2. Assumptions about wall-attached cavity and its erosion 303
.................
8.2.4.3. Realization of the approach 303
..........
8.2.4.4. Erosion rate as a function of the velocity
w,
305
...........................
8.3. Water hammer 306
8.3.1. Celerity, fundamentals of method of characteristics in the
.........................
c,
p.plane 306
...
.
8.3.2. Fundamentals of method of characteristics in the
s
t-plane
308
......
8.3.3. Application of method of characteristics in
x,
2-plane 310
..............
8.3.4. The celerity a in two phase mixture 310
.............
8.3.5. Influence of evaporation and diffusion 312
.......
8.3.6. Boundary conditions in the p, c-plane, loss influence 313
....
8.3.7.
Examples of the method of characteristics in the
c,
p-plane 315
............
8.3.8. Characteristics method in the c, o-plane 319
...............
8.3.9. Remedies against water hammer 320
................
9
.
Similarity laws. characteristics.
research
322
............................
9.1. Introduction 322
.............
9.2. Similarity laws and characteristice of machines
323
....
9.2.1. Criteria of similarity. numbers of Froude. Euler. Reynolds 323
.............
9.2.2. The unit values of speed. flow. power 324
...............
9.2:3. The type number (specific speed) 325
..................
9.2.4. The efficiency hill diagram 330
..........
9.2.5. The cam curves of double regulated turbines 333
.....
9.3. Head and efficiency measurement by the thermodynamic method
334
........
9.3.1. Specific head. enthalpy. component measurement 334
......
9.3.2. Fundamentals of thermodynamic head measurement 336
.......
9.3.3. Thermodynamic measurement of internal efficiency 338
........
9.3.4. Conventional measurement of internal efficiency 339
.............
9.3.5. The scale effect of internal efficiency 341
...........
9.3.6. Several efficiences and their measurement 344
......................
9.4. Experimental techniques 345
...............
9.4.1. Instrumentation for steady flow 345
........................
9.4.1.1. Manometers 345
..........
9.4.1.2. The measurement of velocity by piezometry 347
.............
9.4.1.3. Pressure measurement by air injection 351
............
9.4.2. Calibration of probes for arbitrary flow 352
.....
9.4.3. Methods for dynamical measurements of unsteady flow 352
..............
9.4.3.1. General remarks on unsteady flow 352
9.4.3.2. Velocity measurement
....................
353
9.4.3.3. Measurement of pressure
..................
354
9.4.4. Problems arising with rotating probes
.............
355
............
9.4.4.1. General remarks about rotating probes 355
9.4.4.2. Transmission of values measured from rotor to stationary indicator
356
9.4.4.3. Scanning valve for connection of rotating tappings with stationary
........................
manometers 356
9.4.5. Measurement of the torque
.................
357
XXI
t
..................
9.4.6. The visualization of flov~
359
..........
.......
9.4.7.
Fluids to
be
used in tests
:
360
9.5.
Measurcmcnt
of
unstcatly relative imd nhsolute llow in a Kaplnn turbine
........
by
a
vectorial
probe
of quick response frcm
D
.
C~lsforpli
350
.......................
9.5.1.
Introduction 360
....
9.5.2.
blci~surement of the absolute velocity ficltl of the runner
361
......................
9.5.2.1. Instiurnentation 361
9.5.2.2. Measuring planes, results
upstream and downstream of the rotor 362
............
9.5.3. Measurement of unsteady relative flow 365
......................
9.5.3.1. Instrumentation 365
.........
.
9.5.3.2.
Experimental
results from the rotating probe 365
9.6.
Influence of runner vane number on relative and absolute flow in axial
turbines according to air
tests arid comparative-predictons
by
tK
Kiillnel
366
.................
9.6.1. Formulation of the problem 366
............
9.6.2. Test devices and instrumentation used 367
........................
9.6.2.1. Air test rig 367
....................
9.6.2.2. Layout of the runner
370
................
9.6.2.3. Instru~rlents and probes used
370
..........
9.6.3. bleasurement of flow, discussion of results 371
..............
9.6.3.1. I~lvestigatiot~s of the absolute flow
371
...............
9.6.3.2. Investigation of the relative flow
372
.............
9.6.3.3. Discussions
of
the measuring results 374
9.6.4.
Theoretical computation of relative flow field and coinparison
................
between this and experiments
350
.......................
9.6.4.1. Introduction
380
................
9.6.4.2. The spatial singularity method
380
........
9.6.4.3. Comparison of computed results with measured
384
9.7. Dynamic ~neasurements of unsteady flow near and within the boundary
layer of r11nner vanes by
N
.
F:crtrrer
......
:
..........
386
.......................
3.7.1. Introduction 386
........
9.7.2. Experiments on a Kaplan water turbine model 386
........
9.7.3. Experiments on a Francis water turbine runner 390
9.3.
Investi_gation on unsteady flow in
a
Fraccis turbine by
R
.
Gericlt
and
.
..........................
G
.
1l.f
ollejlkopj'
391
.......................
9.8.1.
.
Introduction 391
.......
9.3.2. Unsteady flow and turbulence level at runner exit 391
..........
9.8.3.
Fluctuations of tota! pressure at runner exit 395
........
9.5.4. Unsteady absolute flow between gate and runner 395
.........
9.8.5.
Unsteady flow in the draft tube of the turbine
397
......
9.8.6. Rerriedies against draft tube surge and power swing 397
9.9.
Laser
Dopplcr anemometer for Reynolds stress measurements by
E
.
Hortner
.
398
.......................
9.9.1. I~ltroduction 398
9.9.2. Example of a flow measurement, carried out by means of a
two
..........
dirne~isional
LDA
with tracking processors 400
.............
10
.
The
turbomachine. its design and construction
403
...........................
10.1. Introduction 403
..............
10.2. Project and construction of
axial
turbines
405
...................
10.2.1. General survey of types 405
................
10.2.2. The true Kaplan turbine
(KT)
406
XXII