11 PELTON WHEEL CHARACTERISTICS.doc

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Last Rev.: 19 JUN 08 Pelton Wheel: MIME 3470 Page 1

Grading Sheet~~~~~~~~~~~~~~

MIME 3470—Thermal Science Laboratory

~~~~~~~~~~~~~~

Laboratory №.

!ELT"# $%EEL

!E&'"&M(#)E )%(&()TE&ISTI)S

St*dent+, #ame+ Section №!"I#TS S)"&E T"T(L

!&ESE#T(TI"#—(--licable to oth MS $ord and Mathcad Section+

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MIME 3470—Thermal Science Laboratory

~~~~~~~~~~~~~~

Laboratory №.

!ELT"# $%EEL

!E&'"&M(#)E )%(&()TE&ISTI)S~~~~~~~~~~~~~~

L( !(&T#E&S= #(ME #(ME

#(ME #(ME

#(ME #(MESE)TI"# №

E:!E&IME#T TIME


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be en#isioned as flow throuh rotatin no&&les. $he pressures withinthe mo#in no&&le produce wor". $he flow must be encased to

contain the water pressure (or suction)' in order that the fluid cannotexpand freely in all directions. Alternately' the #anes must be fully

submered in the water flow as with a ships propeller.

ost water turbines in use are reaction turbines—e#en asimple spinnin lawn sprin"ler. $hey are used in low and medium

head applications. $wo popular types of reaction turbines are the

rancis and the >aplan turbines.n 1?!@' enoit ourneyron de#eloped a hih efficiency (?0)

outward flow water turbine. =ater was directed tanentially throuh

the turbine runner causin it to spin. Bean%Cictor Poncelet desinedan inward%flow turbine in about 1?!0 that used the same principles.

-. . 8owd obtained a D.-. patent in 1?


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Last Rev.: 19 JUN 08 Pelton Wheel: MIME 3470 Page

the product of two factors' the first factor bein referred to as theutilization factor or diagram efficiency is t!e ratio of t!e ideal

work output to t!e energy available for conversion into work . $he#alue of the utili&ation factor may be found from the ideal #elocity

diarams and the enery e9uations. Dnder ideal conditions' it

should be possible to use all of the a#ailable "inetic enery of theli9uid at the turbine inlet and also the enery obtained in the rotor

due to pressure drop (i.e.' reaction effort). -ince the former

9uantity is c g V !!

1


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Last Rev.: 19 JUN 08 Pelton Wheel: MIME 3470 Page !

the tor9ue enerated. or a Prony bra"e radius of brake ' that

tor9ue is

!1 # # brake ==τ

$he forces # 1 and # ! are determined from sprin%loaded scales

(see iure E).

e. or a i#en flow rate' one wants to first determine the Pelton

wheel rpm with no Prony bra"e load' rpmmaC' and that Prony

bra"e load ( # 1 and # !) that Fust stops the Pelton wheel' rpm ;

0. pm is measured usin a laser tachometer.$he Pelton%wheel buc"et #elocity' U ' with no Prony bra"e

load can be considered a ood approximation to the actual Fet

#elocity' V 1. -ince the tor9ue' τ' is &ero for this condition'

horsepower is also &ero ( $% ; τω).

=ith the wheel Fust stopped with the Prony bra"e' thehorsepower should also be &ero.

$here is space on the data sheet for 10 rpms for each flow

condition. n the procedure Fust abo#e' the first and last rpmsare defined. ,ow' di#ide the maximum rpm by 10 to determine

the rpm inter#al such that the remainin ? data points can be

determined. easure the Prony bra"e loads for each rpm.

'ig*re 4—!*m- !erDormance Te+t &ig and !elton $heel

)(L)L(TI"#S

A athcad is supplied below.

Dse the #ariable names already

supplied in the obFect. At the bottom of this obFect is in the

re9uired format the student is tosupply a summary of the @0%

rpm condition. $his alon with

the re9uired plot should be morethan sufficient to e#aluate the

students wor". Kne should be

able to put all their athcadcalculations on one sheet as

shown in iure 5.

$he re9uired plot is as shownin iure @. $he data used to enerate this plot is 9uestionable so

the actual shape of the cur#es is subFect to chane.

Pump and Motor CharacteristicsImpeller OD: 5” № of Impeller Blades: 6Type of Impeller: Open Type of Blades: Backward CurvinTor!ue "rm #en$%: 5” &o$or 'peed (ane: )*+))) rpm

VolumetricMeasuringTank

Sump Tank

Weight Hanger→

←

Torque Arm↑

Pump(see below

Motor

Pelton Wheel

!ucketsPelton Wheel

!uckets

Pron" !rakePron" !rake

PumpMotor

Controller

PumpMotor

Controller

Spring#$oaded

Scale

Spring#$oadedScale

'ig*re 2—ECam-le "ne

!age )alc*lation Sheet


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'ig*re F — Sam-le !lot oD )alc*lation+

#ote= The data *+ed Dor thi+ -lot i+ *e+tionable

Also answer the 9uestions found in the i+c*++ion oD &e+*lt+ and

supply a )oncl*+ion?+@.

&E'E&E#)ES

1. %rinciples of &urbomac!inery' J.N. -hepherd' acillian

Publishin 4o.' nc' ,ew Lor"' 15@.!. =i"ipedia' http2//en.wi"ipedia.or/wi"i/=aterOturbine

http2//en.wi"ipedia.or/wi"i/PeltonOwheel http2//en.wi"ipedia.or/wi"i/rancisOturbine

http2//en.wi"ipedia.or/wi"i/>aplanOturbine


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,-- .,

:= /0- .,

:= ,1+ .,

:= ,-+ .,

:= /0+ .,

:=

2ol1

:= 2ol+

:=2ol

- :=

$1

:= $-

:= $+

:=

∆31

:= ∆3-

:= ∆3+

:=

'U&&"(4 O, T(I"# 1 6)7: m8do$ "c$1

k=m8do$ "c$

219"c$1

f$=219"c$ 219T%1

f$=219T%

T "c$1 .,

f$ lf ⋅

=T "c$ 30 "c$1 .,

f$ %p⋅

=30 "c$ U1 .,

f$

=U

D"T": T(I"# I/D;


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IS)SSI"# "' &ESLTS

=hat two features can be obser#ed from the plot of the resultsR

'nswer)

=hy are the buc"ets desined so that α! (see iure


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(!!E#I:—(T( S%EET

Time

11 PELTON WHEEL CHARACTERISTICS.doc

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