standarization of civil engineering works of shp

(development of an optimisation tool)

ÉC OLE P OLY TEC H NIQU EFÉDÉRALE DE LAUS ANNE

Standardization of civil engineering works of small hydropower plants

Dr Erik Bollaert

Porto 19.10.2004

SE.

ÉCO L E PO LY T EC H N IQ U EFÉ D ÉRA LE D E L AUSAN N E

SECTIONS

1- Purpose

2- Scope of work

3- Typical small hydro

4- Sand trap design

5- Results of sand trap

6- POPEHYE tool


Purpose

Scope of workTypical smallhydroSand trapdesignResults of sandtrap

PURPOSE

ØStandardization of main structures of a small hydropower plant as a function of the design parameters (discharge, head, …) with focus on high head power plants

ØDevelopment of parameterised, design drawings of the main structures and construction cost functions

ØImplementation of the standardized structures in a general applicable optimisation tool for the layout of the hydropower plant: POPEHYE tool


Purpose


SCOPE OF WORK

Design criteria for civil engineering works and structural and hydraulic design of:

üIntake (Tyrolian weir, side intake)

üDesilting basin and rock trap

üFree surface flow canals (open air and buried)

üForebay and transition to pressure flow

üPenstock with fixed points (anchor blocks)


Purpose


SCOPE OF WORK

Standardization of structures as a function of the design parameters

üStandardized geometries (concrete dimensions, constructions details, steel dimensions, …)

üParameterised design drawings with excavation concrete volume, formwork surface and reinforcement

üConstruction cost functions (based on design parameters and unit prizes)


Purpose


SCOPE OF WORK

Implementation of optimisation tool

üReview and generalisation of existing optimisation toolPOPEHYE

üImplementation of standardized structures and cost functions in optimisation strategies

üDerivation of general rules for optimisation strategies


Purpose


TYPICAL SMALL HYDRO TY.

Forebay

Sand trapIntake

Penstock

Small hydro

Turbine & Generator

Network

Weir


Purpose


SAND TRAP DESIGN

Purpose

q To separate the undesired sediment carried by the flow from the water.

Conventional typeq Longitudinal settling tank : It consists of one or more chambers of sufficient

length to allow the sediment particles to settle down.

Sand traps with continuous flushing (system DUFOUR)


Purpose


SAND TRAP DESIGNDesign Criteria (Scheuerlein)

o Identification of the maximum grain size which has to be excluded. Therange of design grain size lays between 0.1 mm and 1 mm.

o Uniform approach flow conditions to the basin which is particularly important when several parallel basins are to be used.

o Uniform flow conditions in the basin itself to facilitate the settling process.

o Sufficient length to allow all particles of design grain size to settle down.

o Installation of a device to clear the basin when necessary.


Purpose


SAND TRAP DESIGNMain part of sand trap : Desanding chamber

Ø For proper design, the dimensions of this chamber must correspond to thesettling characteristics of the design grain size:

ω = ω0 - ∆ω= ω0 - 0.04 Vmc (CAMP formula for the settling velocity in a sand trap)

ω = Settling velocity of sand in flowing water (m/s)

Vmc = 0.44 * (dsc)0.5 Critical mean flow velocity (m/s)

dsc = Design grain size (mm)

ω0 = Settling velocity of sand in quiescent water (m/s) = dsc *g/η *(ρs-ρ)/18ρs = Specific mass of the particle

ρ = Specific mass of the fluid

η = dynamic viscosity of fluid

For application the next fiqure shows ω, ω0 and Vmc as functions of dsc.


Purpose


SAND TRAP DESIGN

1 : Critical mean flowvelocity (Vmc)

2 : Settling velocity of sand in quiescent water (ω0)

3 : Settling velocity of sand in flowing water (ω)

Vmc

ω0

ω


Purpose


SAND TRAP DESIGN

Design of Desanding chamber:Length L, width B and depth H of the chamber must fullfil the following conditions:

L>= Vmc/ω *HB= Q/(Vmc*H)Q= design flow (m3/s)B=H/1.25B<= L/8

Recommendations:§ Extension of the calculated basin length by 10% to 20% in order to

compensate for excessive turbulence in approach flow.

§ Decision upon having two or more basins instead of one in order to be more flexible to react upon undesired effects without taking the plant out of operation (particularly important with respect to flushing)


Purpose


RESULTS OF SAND TRAP

0

1

2

3

4

5

6

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Wid

th [

m]

B_d=0.1

B_d=0.2

B_d=0.5

B_d=1.0

0

1

2

3

4

5

6

7

8

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m 3/s)

Hei

gh

t [m

]

H_d=0.1

H_d=0.2

H_d=0.5

H_d=1.0

Geometry of sediment trap

Width (B) and Height (H) ofsediment trap for differentdischarges (0.5 to 5.0 m3/s).

B

H

Different design grain sizesfrom 0.1 to 1.0 mm have been considered.


Purpose



Geometry of sediment trap

Length (L) of sediment trap for different discharges (0.5 to 5.0 m3/s).

Different design grain sizes(d=0.1, 0.2, 0.5, 1.0 mm) have been considered.

0

10

20

30

40

50

60

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Len

gh

t [m

]

L_d=0.1

L_d=0.2

L_d=0.5

L_d=1.0

L


Purpose



Volume of concrete [m3]

Volume of concrete is estimatedfor different designs based on discharges (0.5 to 5.0 m3/s).


0

200

400

600

800

1000

1200

1400

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Con

cret

e vo

lum

e [m

3 ] Con_d=0.1

Con_d=0.2

Con_d=0.5

Con_d=1.0

Vcon


Purpose



Weight of steel bars [kg]

Reinforcement in concrete has been estimated for differentdischarges (0.5 to 5.0 m3/s).


0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Ste

el w

eig

ht [

kg]

St_d=0.1

St_d=0.2

St_d=0.5

St_d=1.0

Wst


Purpose



Excavation volume [m3]

Excavation volume is estimatedfor different discharges (0.5 to 5.0 m3/s).


0

500

1,000

1,500

2,000

2,500

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Exc

avat

ion

vo

lum

e [m

3 ]

Exc_d=0.1

Exc_d=0.2

Exc_d=0.5

Exc_d=1.0

Exc


Purpose



Concrete cost [CHF]

Concrete cost is estimated for different discharges (0.5 to 5.0 m3/s) and different grain sizediameters (d=0.1, 0.2, 0.5, 1.0 mm)

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Co

ncr

ete

cost

[C

HF

]

PrCon_d=0.1

PrCon_d=0.2

PrCon_d=0.5

PrCon_d=1.0

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Ste

el c

ost

[CH

F]

Prst_d=0.1

Prst_d=0.2

Prst_d=0.5

Prst_d=1.0

Steel cost [CHF]

Reinforcement cost of concrete isestimated for different discharges (0.5 to 5.0 m3/s) and different grain sizediameters (d=0.1, 0.2, 0.5, 1.0 mm)

Con

St.


Purpose



Excavation, gate and site equipment cost [CHF]

For different discharges (0.5 to 5.0 m3/s) and different grain sizediameters (d=0.1, 0.2, 0.5, 1.0 mm)

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Exc

avat

ion

co

st [C

HF

]

Prexc_d=0.1

Prexc_d=0.2

Prexc_d=0.5

Prexc_d=1.0

0

5,000

10,000

15,000

20,000

25,000

30,000

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Gat

e co

st [

CH

F]

Pg_d=0.1

Pg_d=0.2

Pg_d=0.5

Pg_d=1.0

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

200,000

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

Sit

e eq

uip

emen

t co

st [

CH

F]

Sit_d=0.1

Sit_d=0.2

Sit_d=0.5

Sit_d=1.0

Gate Site

Exc


Purpose



Total cost [CHF]

üConcrete

üReinforcement

üExcavation

üGate

üSite equipment

ü….

For different discharges(0.5 to 5.0 m3/s) anddifferent design grain sizes (d=0.1 to 1.0 mm)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Discharge (m3/s)

To

tal c

ost

[CH

F]

tot_d=0.1

tot_d=0.2

tot_d=0.5

tot_d=1.0


POPEHYE

Dimensioning and optimisation of small hydropower plants

Objectives of POPEHYE

- Facilitate feasibility studies of inexplored sites

- Encourage studies with different possible solutions

- Contribute to optimisation of chosen solution


POPEHYE

Computational phases

Hydrologicanalysis of

catchment area Economicaloptimisation of

equippeddischarge

Predimensioning of main structural elementsSTANDARDIZATION

Intake Trap Canal

Surge tank

Forebay

PenstockPowerhouseDischarge


POPEHYE

Main structural elements

Pressurized canal

Free surface canal

Forebay Surgetank

Intake Desilting basin Penstock


FURTHER DEVELOPMENTS …

Detailed design of all structural elements

Compilation of software in Visual Basic

Construction drawings

Language choice

Etc…

Economic optimisation


Thanks for your attention!

standarization of civil engineering works of shp

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