Analysis of Intake System for Modern Pelton Wheel

Reduce Irreversibilities during Passive Actions.…….

deepak kumarProfessor

Mechanical Engineering Department

General Layout of Intake system for HEPP

Power Tunnels : Constant Pressure & Accelerating Flow

High Pressure Piping : Penstock

General Design of Under Ground Power Tunnels

Optimum Diameter of Power Tunnel

• With increasing diameter,

• the head losses and consequent energy losses in a power tunnel decreases,

• While construction cost increases.

• The objection of economic analysis is to minimize total annual costs.

• Total cost consists of the annual charges from the investment and monetary value of lost energy.

The energy lost per day

• The energy loss during particular day i, due to friction is:

ii

i tD

fQE

5

3

7.0

• Energy loss, E

• Darcy –Weisbach friction factor, f

• Discharge through tubine system, Q

• Duration of plant running, ti (h/day)

Monetary Loss due to Unavailable Energy & Annual Capital Cost

N

iii tQ

D

feML

1

35

7.0

Annual Capital cost:2DnCRFC

CRF : Capital Recovery Factorn= Economic scaling factor

Total annual cost, T = ML+C

Niagara Hydro Power Project

• The Niagara Plant Group operates hydroelectric generating stations on the Niagara River and at DeCew Falls in St.Catharines.

• These stations have a total capacity of 2,278 MW.• SIR ADAM BECK I – 498MW.• SIR ADAM BECK II – 1,499MW.• Currently constructing the Niagara Tunnel which will further

increase the output from the Sir Adam Beck complex by 14%.

HEPP with Pelton Wheel

Parts of Advanced Pelton Turbine

• The main components of a Pelton turbine are:• (i) water distributor and casing, • (ii) nozzle and deflector with their operating mechanism, • (iii) runner with buckets, • (iv) shaft with bearing, • (v) auxiliary nozzle. • Auxiliary nozzle is used as brake for reducing the speed

during shut down. • The runner is located above maximum tail water to permit

operation at atmospheric pressure.

Key Parts of Pelton Turbine

Jet Coverage by Bucket during Displacement

Design of Nozzle is of Prime importance in Pelton Wheel

Nozzle used in 62.5 MW Pelton Wheel

Mechanism of Control of Jet dimensions

The Nozzle and Jet : A Key Step in Design

d0djet,VC

Free Surface Shape for Maximum Power

Geometrical Relations for Nozzle

The values of α varies between 20 to 30° whereas β varies from 30 to 45°.

Industrial Correlations for Jet Area variation with stroke

Optimal value of Outlet jet area, ao

2BsAsao

s is the displacement of spear

sinsin2 orA

2

2

sin

sinsinsinB

Geometrical Relations for Nozzle

dO

2dO – 2.4dO

5dO – 9dO

0.8dO – 0.9dO

1.2dO – 1.4dO

1.1dO – 1.3dO

Performance Analysis of Nozzle-Spear Valve

Ideal Nozzle-spear Valve:

constant2

2

gzV

p

Along flow direction

frictiontotal ΔppVp

-constant2

2

Real Nozzle-spear Valve:

penstock

penstockfriction d

fLVp

2

4 2

2

9.0Re

74.57.3

log

0625.0

hD

kf

Pipe Material Absolute Roughness, emicron

(unless noted)

drawn brass 1.5drawn copper 1.5commercial steel 45wrought iron 45asphalted cast iron 120galvanized iron 150cast iron 260wood stave 0.2 to 0.9 mm

concrete 0.3 to 3 mm

riveted steel 0.9 to 9 mm