Fluid Mechanic Xp 3

8/18/2019 Fluid Mechanic Xp 3

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OBJECTIVES

1)To observe the differences between single ,series and parallel p !p operation

")To deter!ine single ,series and parallel p !p characteristic c rves#

S$%%&'(

This e peri!ent is abo t p !p config rations, specificall* single, series, and parallel

p !ps# The e peri!ent re+ ired s to !eas re the flow rates and press re difference

between the three p !p operations# The p rpose of cond cting this e peri!ent is to observe

the differences as well as to deter!ine the characteristic c rves of the single, series, and

parallel p !ps# The para!eters involved in this e peri!ent are vol !etric flow rates, and

different press res - S ction , - .eliver* , - O tflow , and ∆ -)# The res lts in this e peri!ent were

obtained thro gh !anip lating the config rations of the p !ps Shown in &ppendi )# B* the

end of this e peri!ent, an average vol !etric flow rate of 1/#0 23!in was obtained as well

as an average press re difference of 1#4 bar# 5e t, for the series config ration of two p !ps,

an average vol !etric flow rate of 11#06 23!in was obtained as well as an average press re

difference of 1#0 bar, and for the parallel config ration of two p !ps, an average vol !etric

flow rate of 6#70 23!in was obtained as well as an average press re difference of 1#0 bar#

This shows that the three p !p operations possess different flow rates and press re#Theoreticall*, all p !p operations follow the sa!e relationship which is 8 when the press re

increases, the vol !etric flow rate decreases si! ltaneo sl*# Based on the characteristic

c rves Based on 'es lts) plotted, the trend s pported the theor* stated# Besides that, it can

be observed that the parallel p !p has the highest press re which is 1#0 bar, while series

p !p has the lowest press re which is 1#4 bar# In the case of the flow rate, the highest flow

rate is 11#06 23!in which belongs to the series p !p operation, while the lowest flow rate is

6#70 23!in which belongs to the parallel p !p operation# In concl sion, based on the theor*and res lts ac+ ired, the ob9ectives of this e peri!ent have been s!oothl* achieved b t the

res lts and graph obtained are opposite to the theor*#The e planation is in disc ssion#



In this e peri!ent, centrif gal p !ps are connected in series beca se the discharge of one p !p is connected to the s ction side of a second p !p# Two si!ilar p !ps, in series,operate in the sa!e !anner as a two?stage centrif gal p !p# Centrif gal p !ps in series are

sed to overco!e larger s*ste! head loss than one p !p can handle alone# =or two identical p !ps in series the head will be twice the head of a single p !p at the sa!e flow rate asindicated in point "# @ith a constant flow rate the co!bined head !oves fro! 1 to "# In

practice the co!bined head and flow rate !oves along the s*ste! c rve to point A#

• -oint A is where the s*ste! operates with both p !ps r nning#• -oint 1 is where the s*ste! operates with one p !p r nning#

The single p !p !a* be ins fficient to perfo! the re+ ire!ents#Co!bining two p !psincrease the p !ping capacit* of the s*ste!#Two p !ps !a* be connected in series ,so thatthe water passes first thro gh one p !p and then thro gh the second#@hen two p !psf nctioned in series , the flowrate is the sa!e as for a single p !p b t the total head isincreased#The co!bined p !p head 8 capacit* c rve is fo nd b* adding the heads of thesingle p !p c rves at the sa!e capacit*#

5e t the e peri!ent was cond cted in a parallel config ration of two p !ps !anner# @henthe p !ps are parallel !anner, it indicates that the flow rate added# - !ps are operated in

parallel when two or !ore p !ps are connected to a co!!on discharge line, and share thesa!e s ction conditions# @hen two or !ore p !ps are arranged in parallel their res lting

perfor!ance c rve is obtained b* adding their flow rates at the sa!e head as indicated in thefig re below#



Centrif gal p !ps in parallel are sed to overco!e larger vol !e flows than one p !p canhandle alone# =or two identical p !ps in parallel, and the head is ;ept constant, the flow ratedo bles as indicated with point " co!pared to a single p !p# In practice the co!bined headand vol !e flow !oves along the s*ste! c rve as indicated fro! 1 to A#

• -oint A is where the s*ste! operates with both p !ps r nning• -oint 1 is where the s*ste! operates with one p !p r nning

In practice, if one of the p !ps in parallel or series stops, the operation point !oves alongthe s*ste! resistance c rve fro! point A to point 1 ? the head and flow rate are decreased#

& single p !p !a* be ins fficient to prod ce the perfor!ance re+ ired# Co!bining two p !ps increase the p !pin capacit* of the s*ste!#Twpo p !ps !a* be connected in parallel,so that half the flow passes thro gh one of the p !ps and the other half thro gh the second

p !ps#@hen the two p !ps operate in parallel, the total head increase re!ains nchanged b t the flow rate is increased#The head capacit* c rve is fo nd b* adding the capacities of thesingle p !p c rves at the sa!e head#



'ES$2TS:

Vol !etric =low, V23!in)

P Suction

bar) P Delivery

bar)O tflow

bar)

∆ -

P Delivery – P Suction

11#A /#/ /#" /# /#111#" /#/ /#0 1#/ /#61/#7 /#/ 1#" 1# 1#11/#0 /#/ 1#0 "#/ 1#61/# /#/ "#" "# "#11/#/ /#/ "#0 A#/ "#6

Table 1: Single - !p

Vol !etric=low, V

23!in)

- !p 1 - !p "O tflow

bar)

∆ -

P Suction 1

bar) P Delivery 1

bar) P Suction 2

bar) P Delivery 2

bar) P Delivery 2 – P Suction

1

1/#/ /#/ / / /# /# /#411#/ /#/ /#" /#" 1#/ 1#/ /#11#7 /#/ /#4 /#4 1# 1# 1#411# /#/ /#0 /#7 "#/ "#/ 1#1"# /#/ 1#/ 1#/ "# "# "#41A#4 /#/ 1#" 1#" A#/ A#/ "#

Table ": Series Config ration of Two - !ps#

Vol !etric=low, V

23!in)

- !p 1 - !p "O tflow

bar)

∆ -

P Suction 1

bar) P Delivery 1

bar) P Suction 2

bar) P Delivery 2

bar) P Outflow – P Suction 1

#/ /#/ /#" / /# /# /#46#" /#/ /#6 / 1#/ 1#/ /#6# /#/ 1#1 / 1#" 1# 1#40# /#/ 1#6 / "#" "#/ 1#

0# 6 /#/ "#" / "# "# "#4

7#1 /#/ "#6 / A#/ A#/ "#Table A: -arallel Config ration of Two - !ps



Single Pump

ΔP P Delivary-P Suction



Series Confguration o Two Pumps

ΔP P Delivary 2-P Suction 1

Parallel Confguration o Two Pumps

ΔP P Outflow-P Suction 1



DISCUSSION

B* cond cting this e peri!ent consistentl*, we were able to observe the differences

between single, series, and parallel p !ps operation# The e peri!ent was !anip lated to A

t*pes of config rations and to each, vol !etric flow rates, V, need to be obtained in order

to ac+ ire the characteristic c rves#

The vol !etric flow rate, V, was obtained b* !eas ring how long it ta;es, with a

stopwatch, for the fl id in the reservoir to reach 1/ 2# The vol !etric flow rate, V, was

calc lated b* sing the constant vol !e, 1/ 2 over the !eas red ti!e in !in tes# The flow

rates were obtained b* ad9 sting the o tflow press re, - O tflow , fro! /# bar to A#/ bar#

Initiall*, - S ction of single p !p is constant which is /#/ bar for all vol !etric flowrates beca se there is no s ction of fl id sing the energ* b* the p !p and it was the nor!al

flow of fl id# - .eliver* val es were obtained and the graph was plots# The vol !etric flow rate

was calc lated b* sing the constant val e, 1/2 over the !eas red ti!e in !in tes# =or the

config ration of a single p !p - O tflow 3 V), /# bar3 11#A 23!in, 1#/ bar3 11#" 23!in, 1# bar3

1/#7 23!in, "#/ bar3 1/#0 23!in, "# bar3 1/# 23!in, A#/ bar3 1/#/ 23!in# &s the press re

increase, the vol !e flow rate increase# 5e t, the e peri!ent was cond cted for the operation

which involves the series p !p config ration in a fl id flow s*ste!# In this e peri!ent, one p !p is connected to the s ction side of a second p !p# =or the series config ration of two

p !p - O tflow 3 V), /# bar3 1/#// 23!in, 1#/ bar3 11#/ 23!in, 1# bar3 11#7 23!in, "#/ bar3 11#

23!in, "# bar3 1"# 23!in, A#/ bar3 1A#4 23!in# The deliver* press re in p !p 1 - .eliver* 1) is

+ ite si!ilar to s ction press re in p !p " - S ction ")# The relationship is as the vol !etric

flow increases, the press re will also increases# 2astl*, for parallel config ration of two

p !ps - O tflow3 V), ), /# bar3 #/ 23!in, 1#/ bar3 6#" 23!in, 1# bar3 6# 23!in, "#/ bar3 0#

23!in, "# bar3 0# 6 23!in, A#/ bar3 7#1 23!in# &s the press re increase, the vol !e flow rate

decrease#

It was observed that when the press re increases, the vol !etric flow rate also

increase for series and parallel config ration of two p !p b t for single p !p when the

press re increase, the vol !etric flow rate decrease# These things happened beca se the

e peri!enter !ight have error while controlling the valve and !iscond cted d ring the

operation ca sing the fl id does not flow well# Based on the res lts obtained and the graph

plotted, it can be observed that the stated theor* was not achieved#



. ring this e peri!ent, there are probabilities of so!e errors occ rring# One of the

errors that !ight occ r is ph*sical errors ca sed b* observer), which is to read

!eas re!ents wrongl*# B* reading the !eas re!ents wrongl*, the res lts obtained will

deviate so ! ch, and will definitel* affect the trend graph plotted# = rther!ore, paralla error

!ight have contrib ted to the !a9or errors of this e peri!ent# The reason for this is beca se

the observer !ight have recorded the readings while the fl id was still !oving and wasn t

stead* *et, which co ld lead to inacc rate !eas re!ents and res lts#



T torial

F IGURE 1 : S KETCH PUMPS IN SERIRES CONFIGURATION

F IGURE 2 S KETCH PUMPS IN PARALLEL CONFIGURATION



CO5C2$SIO5

&s a concl sion, the operational differences between the single, series and parallel

config ration of p !ps and the characteristic of the three config rations of p !ps b*

co!paring the plotted graph can be collected fro! the res lt and the graph#There are so!e !ista;es that !a* ca se the inacc rac* of the res lt#

The errors are e peri!enter error and e+ ip!ent error# E peri!enter

error occ rred when o r lac; of ;nowledge to

handle the !achine# =or other

errors which is too s!all gap of

o tflow press re val e and

when we switch on the

valve for each p !p, the other valve

which not se did not switch off properl* and was ca se the

press re not persistant and the flow rate is not acc rate#

'ECO%%E5.&TIO5

There are so!e reco!!endation that co ld contrib te to better i!prove!ents in this

e peri!ent# &ll the possible errors that !ight occ r in this e peri!ent have been controlled

in order to obtain the best possible res lts# =irstl*, the s*ste!atic error <ero error) sho ld be

controlled b* chec;ing the !eas ring device prior to the e peri!ent# 5e t, paralla error

sho ld also be controlled b* confir!ing the !eas re!ents with gro p !e!bers# Instead of

that, all the config rations of the operations single, series, and parallel p !ps) were

followed e actl* as shown in the laborator* !an al# This is to ens re that there are no

!isoperation that co ld lead to inlogical res lts# %oreover, an* fa lt* e+ ip!ent, da!ages,

lea;ages, and nsolved errors sho ld be reported to the technician i!!ediatel* so that theo tco!e co ld be the best# The laborator* !an al ! st be read beforehand so that no ti!e

will be wasted in cond cting the e peri!ent, as well as to ;now briefl* on what this

e peri!ent is all abo t#



'E=E'E5CES

1# =l ids %echanics = nden!ental and &pplications ,=irst Edition , ( n s &# CengelJohn %#Ci!bala

"# D&non*!o s, "/1 , http:33en#wi;ipedia#org3wi;i3- !p , D1th %a* "/13. %cFraw?>ill Concise Enc*clopedia of Engineering# G "//" b* The %cFraw?>ill

Co!panies, Inc#4# D&non*!o s, "/1 http://www.cheresources.com/invision/blo /!/entry-"22-

multiple-centrifu al-pumps-in-series-an#-parallel/# D&non*!o s, "/1 http://www.en ineerin toolbo$.com/pumps-parallel-

serial-#%&"&.html

http://en.wikipedia.org/wiki/Pump

http://www.cheresources.com/invision/blog/4/entry-322-multiple-centrifugal-pumps-in-series-and-parallel/http:/www.engineeringtoolbox.com/pumps-parallel-serial-d_636.html


http://www.engineeringtoolbox.com/pumps-parallel-serial-d_636.html






http://en.wikipedia.org/wiki/Pump

Fluid Mechanic Xp 3

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