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0% found this document useful (0 votes)
60 views11 pagesLesson 4
Uploaded by
naverfallCopyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
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/ 11
> MER with Frehon 105)
Sorehmes the -tacher des rater On rportert Caster
to to mechonial O79) solo
J
Tor example: ch m pipe choweler
tebe |
Avens in the pipe
ory lot
B(e = Ws,0
u ate) + gaa +F A
For liquiel flows in straignt epes te fazhonc| losses
ovo comelated in Jers of the Cannig. proton laclorsds
gs a fanchor of thu Reynolds number, e+
Qe Fann ing Erehon factor § defined a2 a cimersionless
vol fora strarph> dbes , ane its relahonship +2
pressure drops » flew rates Orc! eome tne focters may
be understeed by considenry. tun mechanical crepy
balance Applied to O stroup at cechor Sf pipes
Fxouple + For a Neptonion furl p Wat is the fren
term Fon te mechanical every) balonce for sade
Pow Wo tube?
© ae)
je
PL _s p '— Pa
‘ 3 e
ie ———
‘ io) --~-!
2 force 07 woth
=—fre 07 Suid Bepin with He mechoniat enepy balance :
Ae 4+ bt) +ahe = Ws
¢ a a
® There % 00 pune or moving ports i our chosen
splem =) Wejon =O
® MWe pipe wil hae a constort flow mate vel canter
Cross Sechonal even =) Qt- G =O
pe
@® Tre ppe s horizontol 3 Bo - R= O
Nechania| enerpy- baloree become
Pa— Pa 4F=0
f
the fatheral term ©
_ Par fe Friern n Stead
Faso pre Pp Flaw in Prpes o
sre fanninp Erichen poctor F'5 dapred
Ps voll Foree
= (fe- ) RR?
(27RL) [de low
The relahon wodl force 3 (Pape) AR uo obbained
5 womenhen
balence on +VO
slraupwr pipe cai
Friuter Factor
Fannity ay
mensional onalyas delle vs that for steady flow ¥
@ Rapin Pid ina tube , the Fforniry Prichon fecto
& only © Guunchen a} the diverenter quntiy poo D /y
which 1s. Peynokls number
Example : What 6 the relahonship between the Fonning
frrnon factor gang the Reynolds nnurvber Be
tor sleacly , Laminar flow in o hibe ?
he result for Mouton Puads s calles fae
Hagen - Porseuille eqn
28 L Qn lous
Pi- Po = Se eae Bran th o habe )
Wie (yc a © Plew vale m the tube
Bou » averyge | tui velociny
The Fanning freho factor : foe Com mor flow
In a tbe 7
g. Gch) be spon >
2b (ov)* 2 (bavl*p
= tbe = de
P Vou d Re
eres for = 1b /py Fanny Grichen Factor m Steady louuner For laminar flow 3 = 6 /py
for turesentd flow = comrelahon: | Colebrook formula
~ mo bee / by 48),
e( e+ ek 2:26] Colebrok
- Sd een see ee forcalos
a Surface roupness Peroweter
une = k/D >
for uortaus rnatencls a” piven in Table pion 28
corre Cohen 1 pleted In Fipure 240.3 Cp 88)
Th acldthon te Wall drop in straipht pipes , Hwe oe
mony other sowces q feaho m ppg, sypleus: valuess
Garhngs » pumps» expansions ancl cortrachews Ve ot
souweer farton.
For values 1 fithngs expansions ainel contractors the
dala correlahens +e results Grom scl analyses ray
ye wrttien in +he follows, form:
Kp Cau)?
Fre kp Qo) ache prom Fethngs
Tre trehon coethuents Ker are dibferen+ Ror
evey type oy value, Yttwp etc. ( oot af Table 2.10-1)
(pp 293 / Georkspls ) the ferhon = for a wmelete Piping, syptem will
be equk to the frchon due to rhe strayeh? papes plus
ne 4richen ame to tach ob the values, fithngs ,
expansions and contrachors Hat are Present im the
Flow loe
Fp = 4G Ew TB]
Systane OF fs |
|
= pipe septs
where? cag to be wee in exponsions od
convechons 15 the foster cuarpe
Selocity
On expensior
Cupsireorn veloc fe
glowastremn a Conacho)
average velocihg. nw the steayoltt pipe
For expansions ond contrachons ,
2
Key = 4 (4 a expansion tom Ai toe
ket = SE (1-8) oman tenn
Ag > upsiveon Cross Sechorce| oea
i ‘ 4
Ao = Clounstraon ®
Ker cot « Ux ote thet hoy aa type oth
shed ( ty thins
Stun faclon losses m low Frou a shratewnt pre om ke
coleatate 4 Using " fannry Preher factor”, Houewer yf
tho valocty gy the fdud & chayecl m the diechon
or rrogmimce ,oclelihenet father less occurs,
dos ilegsrsh Freres
a) +H the Ces sechor a ppe
=o Ae s very gradually ) aw,
a ae or Ab extra lossse oe
MWeured.
—Is55) +f the choye & svdelen ) F results
J 2 le
z m addiherak tosses clue
oo
~ Le 27\ edehe s frre d.
Ths fnchomt Goss cn be colealoted by AML Lotlouys
be turbulent flow mM beth sechor
jroo
2 a Pea loeh
muna (FB) URL SEY
fal a 20 yy
t K
€Kpansiorn— Ayal
loss
coe fheumt
Ip the flows toner jn both tech. d= Yo
en Len the cross—sechen ef pipe ©
) i srdeenlg- cecluaed j addihoral Archon
losses oravs due K edie s o velo an 2
fp morta #°
hee oss (1 2 WL Ke, Be he,
a) 2a = yo oa b
TT otel for debs
For hubvlent Plow
her °
loss Coen :
Ken O8F (* - fa
aA
For dower flow l= Va
La rn FB ingat ool Blues
Pye +tvps orel values also chetrbs the nornal flow
pres a pe ae cone ade. Preherel Awss.
Th a chat pipe wth men Fittwps , tre frichen
joss rom thee farhyps covlel be Grester Hen thee
straigyt ‘pe.
2 as ov. Veloct
ym the spe
y= & be Lendip te ee re
/ a
lose acter for Prhp
or Yale
Table 2-10- 1 fee Lona Ce yoluns read
geod for ER
Or ee ef
du v2 Ce ye eee
ate yFhe yy thas 2 445
4 all yeloeme? Ce some Ca = 97
— lap De ake th)
ata (afte + bex B\s
Sole Exp 21-6 J 210-% 20.02 Plmia
Talus ale the elect of
Pathe
[sm 12m
Rowanber 9 rh = 0:33 kple
Allow
sunen € Ue dlr 2 &= 45" % Terolent
Jb
~»
=
"
o
g
oe
Frond <= B= 0.07smle
ase iy yaad
I tf F 2 ° 2
Shawkt pipes DDFS 2 Iswe
MWe Sen 29 124242346 = 43m
Lu plte) = Fomy Porton factors ove found Bom Colebrao a dr
J. 0.007693 2 sb=5e
gb 0,00648