1A P- -cV, 7m the variation in the level in the float well at C due to auttiog off a delivery of 20...
Transcript of 1A P- -cV, 7m the variation in the level in the float well at C due to auttiog off a delivery of 20...
1"A P- -cV, 7
OFFfc-f -
F 1 L E c 'C", F y BUREAU OF RECLAMATION
HYDRAULIC LABORATORY
Mmmw
HYDRAULICS BRANCH OFFICIAL FILE COPY
OPERATING RESULTS
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Denver, Calm-ado 14 H. G. Curtis October 1,3, 1952
Throught Chief, Fngr. Labs Branch and Acting Chief Designing Engineer R. E. Glower and C. R. Daum
Operating results tram the Delano-Urlirart dMtog
1=cduct o
The proposed Delano-8arlinart pipe line is to have a length of about 7 ales. The maximm flow to be carried is 60 cubic Peet per second and the head differential between the two ends is 120 feet, In order to reduce the pressure em the lower end of the litre# it was proposed to install two pipe stands to divide the total length into alp mdaistely three equl parts. A float-aantrolled valve in each of tiho two Stan" would automatically maintain the water levol in the two pipe stands so that deliveries coWA be merle or diseoatinaed at any twuout along the line as desired. Such an arra"mmm Yt is advautageoas from an Operating staadpedert. It was desired to whether any
stable types of operation or mW type of self-induced oecillation would be experienced with this arra 1111 nt. An ehectric analog we chosen as the quickest and ahsapost way of stadring these pesa~lbilitias, The regwat for this study is contained in your men~warandruK of June 20 19329 to Wo Glower cm "InmAlgation of bydnnUo characteristics of a float-eontrolted valve for use in the 3lelam0-riarlima-t Irrigation District ,ea--P riant-Fern Canal Distribution System--Central Valley Project."
The analog was built to represent a pipe line 36.000 feet long divided into three 12,000--fort rswhss. The pipe diameters in these reaches were assard to be 48, 38, and 24 inches, respsetiva2y. This float vo lle were assimed to have a diameter of 8 feet m d to be equipped with flout-aunt vllod valves could► be closed from the apon position with a float travel of 2.6 feet. The water-haxner wane velocity is the Line was eetisatsd to be 10043 feet per second.
Analogous quanntities in the hfdraulic and electrical system are as obown In the following table.
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PIRRI-lyll Flow of Mater Ourrent and #01tap
a "PSOMW —41 tame, Friatian
The flesh-operated waves vere reWesentod byvacom tleb" idth
the aid eirevi to arrwkpd sO that a. ra.ae in vol taps acted to eut off the flow of current three& tlt tubs. A ram t"s, the pluso of the ditch rider to turn the flan an and off.
The appearm=* of the finished axsllct is shown in rip" 1. A diagram shmAng the electrical.rauit is show is Pion 20 The aeri psaiim-g hydrmlic sad slectrieil *WA*Ume are shown In Tahle Il.
RIMRABLIC AND BULTWAL RWATTOMS
f dral.i c ieatri+oal.
Ctt 4 ail,
@x A& @t it
ql , pl 2NL - q2 - C Cmt'maty - K dt - 12 . 4 dt
h 4W AS dt diiial
lq ua►tims, l~
Mar to the WOUX-i *"mm in the i&P reachm'. gquatieets 2 see far the •feet of OvWWWWe sad i~n1. flv shi+aaae in the flast mulls. Zie subscripts 1 asd 2 refer to the r44bs votram std d oom frma . the float , respectiv . The lea used i s defied as fou m l
(2)
2
h *drag Ue Weesme ( feet ) x dintaue in the h2+draaaU Watm
in {
t o e ~ ~rA ) ( smonas) tie in thi analogy (~raeaAds~
xarre ~Aslooit~r f't/ae~~ A ~ sert3
tiva of ~ C pile ~ 2
F aar*a of cross Smuce at a float wall Ut)2 L lagth of a pipe r wh (feet) q amity Of flan in Us i =U* rgrvstM (ft3/000) Is voita®e in the aM.ies (Vol-to) I currek in the aoalms (moms)
imWetnea Per fees( in the analgg (Now7t o foot) C capaoitsme per foot in the male& (t`aradls foot)
J incapacitance
taaas a i 's In a rt t f sHsm►es)
The aorrelatim equations ere=
h I t 30,000 n (3) Q -10,0001 : = 10,000
L The d1now ions of the asoleg parts are an fa►U omt
2n the #t-inch diarter Lim -
Lw4m 1.2 feet ~l 4.930 FmWfoot To a7. 3.916 'e!6 C, _ 0007424) (10)"6Fmrades/foat Total 0909)(30) Fear rl - 670 dm
Capacitalm reMesenting obarap in first float W11 (0.1) (10)'6 Fared
In the 38-Inch diameter Lim A
A2 - 7.862 Heurs/foot Total 9.4X Rewfle
C2 - (OD4659) (10)4 F*rsdesefoot Total (00591) (10 r2 - 11000. dm
3
a 3 - 19.781 R*ur7Vs/toft Total 23.737 He=71 t
C3 (007.850) (10)-6 Faraidle/foot goad (0! 4) (10)-6 Faradle r3 38000 dm
The relay was driven by a frequmiy generator at rates varl►tmg fraa about 20 to 30 eyous per eecend. VMS gave saffuient ties for mmillatiewau to the dew in the amalog a irmdta. Each cycle reprosented Mw mkb% of a deliver and It* adbinqmoft diseaatimmuce. Mw
valve Vas 2ew br a 6AC7 tube car acted as a trial*. The entpatt of the wSag was obsery biy mm of an osaillv~araph as sho m in Figwo 1.
No instability or t*> mmoy to ante,-oftitlatiou was d"m at any tit*. Sim* the float-operated valves gill cmgpletely alai off the flow if the water level in the float van* rises 2.6 feet, as aroUtude of oeofllation greater than this is dlfflou :t to prodwe. The most striking featwo of the *artily traces is provided by the *sharp prearm o rises dime to water f*Uov* valve closures. The pressure rises sham by the analog cheok clorely vitb car xrW va'lwes.. The electrical arramamasa of +sale aamal.eg car, spoods to a hpdramlic pipe Lice* with float-oaftroiLled valves which we ** m Amt4Iy balanced. If the Ym: 7" wars ud al.am so that water4mwmsr p vsowrsa womtld tend to open tbm@6 the water. hammer pressers would be reduced.
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ReACH I REACH 2 REACH 3
`s0 C FS
A M- C
9 E
r r
HYDRAUL IC S YSTEM
ELECTRICAL EI G URE Z AN ALOG
r: 1--A4V*&ran0* of the asaWleW aaalet. The thres vertical bastae of **Us "Present #ohs ilia of the vater, in the, three pipe reaches. IN awl cowl eawars ad jaoo* to Vasa represent the sterage caws ity Present in the 'Line dare to its expawics doe to parssswo. fte tro tabes between the three can banks """out the float traa v w. ?eve large ca d*nwrs just to the left of *ash ot" the tubes r*Vressat the stamp capacitor in the fleat rwll. The r*IW at the rlget sod Of this Powl turns the current an and off to represent flow changes in the Votem. Four reading m tern a +d an osaillo Capp we shwAn.
IR
F,gts 3--This figure shoots oannectiom an the beak &ids of the panel sho m in liSWe 1.
This trace ahoMr the Yariativ3, of level in the fleet v*" at C due to cutting off 34 aubia feet per second at B Mgwe~v+eries wtially 60 cubic feet per O"Od enteral at A to stipplf of 30 cubic feet per s"Ord at B 20 aubis feort per aecaad at D, wA 14 cubic tart per 04MA at Fe ' A; male of this
trwA is such
~ rise hat
each of the s=13 sosU divisimas ra~eo~s about 4. The total. rise is abmt 2.3 f"t• A s greater rise is not poo~erib3s lriaae the flmai 4alw
cuts ~ ~~~ ise ?fir °~
toot. The trace shOM are ls of the trace is 1/50 aeaaad. TM ogodvalm t P01 *AM period for the hydraulic oveillatiod fonowing cloatue is fib mss•
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-pto O#jv gv^ uw *Tq3 wj po' .1 10 Vto*' .tad vwa
ywM moo .nd 14001 *T OC 'k Opmom asd +"j *TW 09 3O
sir ~ ~~ UT 0 s ;o vTWO Olu ` ($ *m ) m.~ ~ ~ a ITM *1 *up a '4v .4v ~~ aid TOT
OAX
©Q
UO a etr4 U ~x.~ SM TTY % UT~
This Abe - m the variation in the level in the float well at C due to auttiog off a delivery of 20 cubia foot per socced at D. Prow ion to the oototf, 60 anbie foot per secoad was flomiag at A to xggd ► deliveries at 30 cubic feet per soca d at 8, 20 aabic feet per owed at D, snd 10 cubic feet per mooed at F. The reeood indicates a oemplete closare of the Host-aaatrolled va ve The sweep frequemr in this *sae is 50 cycles per secand and ace email division repeesents sppeaadwately 0.1 farm on the vertical scale. OpeniM prednaes Delp' about 0.7-foot drop is the water level in the float roll..
k-- -1
This record show the shasgo:i of level in the float well at L due to a cycle of delivery and cutoff of 20 cubda Vest per second at D. Inflow to the pipe is 60 cubic test per second, with 30 cubic feet per second being delivered at H, 20 a0ic test per seewd at D, and 10 cubic toot per ama d at F. Tho trans sweep fftqusnay is 50 cycles per ***road and the vwUcal scale is about 0.1 Foot per each s ill. divi icku Waking the delivery canes* only a tsw@oe'Lry drop in the level in the float v*U, but
ing oft the delivery produces a dssped cesillatian of the In.
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This to a cad. brafiian trace for the records shr4m an Photographs R-1063-3 4, 5, and 6. The pa Lk to peak vertical distmee represents 1.0 volts. This is equivalent to 1.8 feet of va►ter in the hydraulic system.
11
0
12
This trace shwa the flow changes in reach 2 due to cutoff of 30 rabic foot per seoord at Be Before the charge, reach 1 carrie 60 cubic feet per seaa d, reach 2 carried 30 cubic feet per seamd, and reach 3 carried 10 eubic feat por seoord. After the change, reaches 11, 2, and 3 oarri.ed 30, 30, and 10 cubic feet per seaood, respectively. The trace is inverted so that an inerease in flaw is shorn bT a dowumard swiment of the trace. On the vortical saa s one sdall division sepmsents abort 1.4 cubic feet per secrrmA. Ths trace sweep frequency is 50 *"lox per seeond. One sweep 0 19000 se W46 in the prototype.
This trace shows the flow changes in reach 3 due to cutting off 30 cubic feet per second at B. Prior to the change the flog in reaches 1, 2, and 3 was 60, 30, and 10 cubic feet per second., respectively. On the vertical scale one small division represents about 0.13 cubic foot per second. The disturbance caused by cutting
_ off flow in reach 1 dies out rapidly and is almost nonwdstent in reach 3. This trace is also inverted in a manner similar to that of H-,1063-8.
This sUbratiag trAm appliAw to the rwis sham an Photographs X-1063, -S w d q. The voltage changs is 1.8 volts trcm xdnium to Wit.
TUs tr"o shown the pressures at F due to cutting off 10 cub foot per need at F. Prior to Us ahmp the" was 10 cubic feet per second flmirg in reasbas It 2, wd 3. The trace, tbas jwuAxtes vater-ha=w pwoureis due to a amplete euWf - One *W3 diviidonof the Vertical So&U mmssfts ~ 3 foot of bagd. The bor"ORWI ~p f*oqu*W is 30 qyclos per secuds k flow of 10 cubic feet per nowd in rwh 3 vv4A Prodwe a velocity, *f 3.18 feet per womid. The ostimted water-homer hard due to skmttinig off this flow is 103 feet of eater. The so" promme rise is " fwA*
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This tram shows the tortissszoo 4t D Title to cutting oft 10 cubic teat per "*ad at point F. BefwO autofe this 10 pubic !*et per meand was the entire flow it this litre. On th vertical. scale me wail. division, represents about 3 feet of head, A flaw of 1.0 cubic test per seoaad in reach 2 would produce a velocity of ..26 Peat per mcoc+d. In the pipe as described a aa*ats atvppw of 1.0 foot per seaced woWA produce a hs*A rise of 32.43 feet of water. An i.astaataneoww nlosure iu this aarse wmd produce 40.9 feet of pa%ssurs rice. The tress shear 27 test.
e ditfvrsuao is da to the relief Wardod by flee slow *lava* +at the fI0&t-viper &ted valvv o
I I
I%e trace shoes the ;"mm changes at point S duo to 'MF-mmW shutting off a flov of 10 cubic feet, per second at point Fo Baton elm" this 10 cubic foot per asoond was the entire flow in the Line. A flow of 10 cubic foot per moad in reach 1 would create a velocity of 0.794 fact per mmend. An instantamous, olosumm"A.6m would produce a press=* ries of 25,8 feet of water* The tr4WM indicates about 19.5 lost rise. Tke reduction is due to the slow operation of the float-cantroLled valve. In the eyule of open ag and cloture shams, the opwAng operstion webw" a pnsswo drop iddah Is larger tham the Weemm Am *& eloms* Sisk" the pipe MAftom 10" is low for thine flowo the head lon at the float VaVe, eammum newly All of the statis head. per tug reason the trace does ftft show mah 5"tia Proof=* ohmse an claeuxe.
17
1016
This ca2lbrat4ng trace appUox to the rms shorn cm -7.1
lPhatcg"WLW R-2fl63-Ut 12, acrd 13. The varki.cal iatsmept ietw en wi.nimm snd modam repressnts 240 volts chanp-
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J
Ldj
0
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Pictures H-1063-16 to 19, inclusive, show traces obtained from oscilloscope having a direct current amplifier. This amplifier permits showing of the traces with reference to a zero pressure line, shown at the bottom of the picture. The initial flow of 60 cubic feet per second in the line supplies deliveries of 30 cubic feet per second at B, 20 cubic feet per second at D, and 10 cubic feet per second at F. All of the traces were made at 30 cycles per second. S..ach small division of the screen represents 5.45 feet of head in the vertical direction and 64 seconds of time in the horizontal direction. The four traces show the results of changing the conditions as follows:
Table III
Picture Flaw out off Trace showed pressure
16 30 ft3/sec at B C 17 30 j%3/sec at B E 18 20 ft3/sec at D C 19 20 ft3/sec at D E
The oscillations shown on Picture 16 are shown in magnified foam on Picture 3. Pictures H-1062-22 to 24, inclusive, show the results of cutting off 10 cubic feet per second at F. The original flog in the line was 10 cubic feet per second throughout. The trace frequency in this oscillogram is also 30 cycles per second. The pictures show a sequence of opening and cluing of the gate at F. The conditions recorded are as follows=
rdote that in each case the intercept between the zero Line and the trace following closure represents the static head. On the three traces these are 120, 80, and 40 feet of water, respectively.
17
G,~', q aAA.rW
19
Table IV
Picture Flow cut off
22 10 ft3/sec at F 23 10 ft3/sec at F 24 10 ft3/9ec at F
Trace shows pressure at
D F
r~
r
c
0
I