1、Designation: D 5716 95 (Reapproved 2006)Standard Test Method forMeasuring the Rate of Well Discharge by Circular OrificeWeir1This standard is issued under the fixed designation D 5716; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers construction and operation of acircular orifice weir for measuring the discharg
3、e from a well.This test method is a part of a series of standards prepared onthe in situ determination of hydraulic properties of aquifersystems by single- or multiple-well tests. Selection of a welldischarge measurement test method is described in GuideD 5737.1.2 This test method is common to a num
4、ber of aquifer testmethods and to evaluation of well and pump performance.1.3 LimitationsThis test method is limited to the descrip-tion of a method common to hydraulic engineering for thepurpose of ground water discharge measurement in temporaryor test conditions.1.4 Much of the information present
5、ed in this test method isbased on work performed by the Civil Engineering Departmentof Purdue University during the late 1940s. The essentials ofthat work have been presented in a pamphlet prepared byLayne-Bowler, Inc.2and updated by Layne Western Company,Inc.31.5 The values stated in inch-pound uni
6、ts are to be regardedas the standard. The SI units given in parentheses are forinformation only.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health p
7、ractices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 5737 Guide for Methods for Measuring Well Discharge3. Terminology3.1 Definitions:3.1.1 circular orifice weira cir
8、cular restriction in a pipethat causes back pressure that can be measured in a piezometertube. Also called orifice tube and orifice meter.3.1.2 control wella well by which the head and flow in theaquifer is changed, by pumping, injection, or imposing achange of head.3.1.3 dischargeor rate of flow, i
9、s the volume of water thatpasses a particular reference section in a unit of time.3.2 For definitions of other terms used in this guide, seeTerminology D 653.3.3 Symbols:Symbols and Dimensions:3.3.1 Aorifice plate open area L2.3.3.2 Ccoefficient of discharge for the orifice nd.3.3.3 gacceleration du
10、e to gravity LT2.3.3.4 hhead in manometer L.3.3.5 Qcontrol well discharge L3T1.3.3.6 oorifice diameter L.3.3.7 dpipe inside diameter L.4. Summary of Test Method4.1 This test method involves pumping a control well at aconstant or variable rate for a given period of time. Dischargeis through an orific
11、e weir that allows determination of thedischarge rate.4.2 This test method provides design information for con-struction of an orifice weir. It also describes setup, operation,inspection, calculation of discharge, and reporting.1This test method is under the jurisdiction ofASTM Committee D18 on Soil
12、 andRock and is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved Sept. 15, 2006. Published November 2006. Originallyapproved in 1995. Last previous edition approved in 2000 as D 571695(2000).2Measurement of Water Flow Through Pip
13、e Orifice With Free Discharge,Bulletin 501, Layne-Bowler, Inc., Mission, KS, 1958.3Measurement of Water Flow Through Pipe Orifice With Free Discharge,Layne-Western Company, Inc., Mission, KS, 1988.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service a
14、t serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 Many mathematical equa
15、tions for determining aquiferproperties based on controlled field tests utilizing a single ormultiple-pumping wells include a dependent variable, termeddischarge, and generally designated as Q. Equations have beendeveloped for constant and variable discharge. Those forvariable discharge may specify
16、regularly increasing, or regu-larly decreasing, or randomly varying discharge rate.5.2 Aquifer testing has been conducted for the purposes ofproduction and pressure relief well design and water resourceassessment. Production wells are used for public and industrialwater supplies, hydraulic controls,
17、 and ground water capture.Pressure relief wells are for hydraulic controls. Test wells arefor the purpose of water resource assessment.5.3 Discharge must also be known for certain methods toevaluate well and pump performance.6. Apparatus6.1 Construction of a Circular Orifice WeirAconstructiondiagram
18、 of a circular orifice weir is presented in Fig. 1.5Thecircular orifice is a hole located in the center of a plate attachedto a straight horizontal length of discharge pipe. The pipe is atleast 6 ft (1.8 m) in length. Twenty-four inches (609 mm) fromthe end plate and at least 4 ft (1.2 m) from the o
19、ther end of thedischarge pipe, a manometer is attached to the discharge pipeso that the head in the discharge pipe can be measured.6.1.1 Orifice PlateThe orifice is a round hole with clean,square edges in the center of a circular steel plate. The platemust be a minimum of116 in. (1.59 mm) thick arou
20、nd thecircumference of the hole. The remaining thickness of theorifice should be chamfered to 45 and with the chamferededge down stream.6.1.2 Discharge PipeThe discharge pipe must be straightand level for a distance of at least 6 ft (1.8 m) before the waterreaches the orifice plate. This approach ch
21、annel should belonger if possible. The end of the pipe must be cut squarely sothe plate will be vertical.The bore of the pipe should be smoothand free of any obstruction that might cause abnormal turbu-lence.6.1.3 ManometerThe discharge pipe wall is tapped mid-way between the top and bottom with a18
22、-in. (3.17 mm) or14-in. (6.35 mm) hole exactly 24 in. (609 mm) from the orificeplate. The manometer should be a distance of at least tendischarge pipe diameters from the gate valve used to controlpipe flow. Any burrs inside the pipe resulting from the drillingor tapping of the hole should be filed o
23、ff. A nipple is screwedinto the tapped hole. The nipple must not protrude inside thedischarge pipe. A clear plastic tube 4 or 5 ft (1.2 or 1.5 mm)long is connected at one end to the nipple. A scale is fastenedto a support so that the vertical distance from the center of thedischarge pipe up to the w
24、ater level in the manometer can be5Driscoll, F. G., Ground Water and Wells, Johnson Division, St. Paul, MN, 1986,pp. 537541.FIG. 1 Construction of a Circular Orifice Weir5D 5716 95 (2006)2measured. Alternately, a u-tube manometer or pressure trans-ducer may be used. During a test the manometer must
25、be freeof air bubbles.6.2 The water level in the manometer indicates the pressurehead in the approach pipe when water is being pumped throughthe orifice. For any given size of orifice discharge pipe, the rateof flow through the orifice varies with the pressure head asmeasured in this manner. Table 1
26、 presents the flow in gallonsper minute (gpm) for various combinations of orifice and pipediameters.6.3 The diameter of the orifice should be less than 80 % ofthe inside diameter of the approach channel pipe.7. Procedure7.1 Set up the apparatus as shown in Fig. 1 and Fig. 2. Theapparatus should be s
27、et up so that the orifice pipe is horizontaland the discharge is unimpeded. Use a combination of pipe andorifice diameter so that the anticipated head will be at leastthree times the diameter of the orifice. The orifice plate must bevertical and centered in the discharge pipe.7.2 Equipment should be
28、 inspected to minimize the poten-tial of wear, damage or misuse causing increased head loss thatwill bias results.7.3 Initiate flow through the discharge pipe. Check that themanometer is free of air bubbles. Record the manometer level.Using Table 1 for the appropriate pipe and orifice size, read the
29、discharge.8. Calculation8.1 Calculate the flow through the orifice using the basicequation:Q 5 AVC (1)where:Q = the flow per unit time,A = the area of the orifice,V = the velocity of flow through the orifice, andC = the coefficient of discharge for the orifice.The velocity of the water at the orific
30、e consists of its velocityin the approach channel plus the additional velocity headcreated by the pressure drop that occurs between the connec-tion for the manometer and the orifice. Because the waterdischarges at atmospheric pressure, the pressure head indicatedby the manometer can be converted to
31、the velocity if friction inthe pipe is neglected.8.2 Relate the velocity to the head in the manometer by theequation:V 5 =2gh (2)where:V = velocity,g = acceleration due to gravity, andh = the height of water in the manometer.To compute the actual velocity through the orifice, the valueof V from Eq 2
32、 must be added to the velocity in the dischargepipe approach, and the sum of these must be corrected by twofactors. One correction is for the contraction of the jet streamjust outside of the orifice, and the other is for the suddenchange in cross-sectional area of flow which is controlled bythe size
33、 of the orifice relative to the size of the approachchannel. The approach velocity and the two correction factorsare combined into a single factor, C, whose value varies withthe ratio of the orifice inside diameter to the approach-pipeinside diameter as presented in Fig. 2.8.3 The equation for flow
34、through the orifice is:Q 5 CA = 2gh 5 8.025CA=h (3)TABLE 1 Flow Rates Through Circular Orifice Weirs5,ANOTE 1Flow rates indicated below the line are more exact than those above the line because the head developed in the piezometer tube for particularpipe and orifice diameters is large enough to ensu
35、re the accuracy of results obtained from Eq 5.Head ofWaterin.4-in. Pipe 6-in. Pipe 8-in. Pipe 10-in. Pipe 12-in. Pipe 16-in. Pipe212-in.Orificegpm3-in.Orificegpm3-in.Orificegpm4-in.Orificegpm4-in.Orificegpm5-in.Orificegpm6-in.Orificegpm6-in.Orificegpm7-in.Orificegpm8-in.Orificegpm6-in.Orificegpm8-in
36、.Orificegpm8-in.Orificegpm10-in.Orificegpm12-in.Orificegpm5 55 89 76 145 131 220 355 310 460 680 300 580 530 880 14206 60 97 82 158 144 240 390 340 500 740 325 640 580 960 15607 65 105 88 171 156 260 420 370 540 830 350 690 620 1040 16808 69 112 94 182 166 275 450 395 580 880 375 730 670 1110 18009
37、73 119 100 193 176 295 475 420 610 940 400 780 710 1180 191010 77 126 106 204 186 310 500 440 640 990 420 820 750 1240 201012 85 138 115 223 205 340 550 480 700 1080 460 900 820 1360 220014 92 149 125 241 220 365 595 520 760 1170 500 970 880 1470 238016 98 159 132 258 235 390 635 555 810 1250 530 10
38、40 940 1570 254018 104 168 140 273 250 415 675 590 860 1330 560 1100 1000 1670 269020 110 178 150 288 265 440 710 620 910 1400 590 1160 1050 1760 284022 115 186 158 302 275 460 745 650 950 1470 620 1220 1110 1840 298025 122 198 168 322 295 490 795 690 1020 1560 660 1300 1180 1960 318030 134 217 182
39、353 325 540 870 760 1120 1710 730 1420 1290 2150 348035 145 235 198 380 355 580 940 820 1210 1850 790 1530 1400 2320 376040 155 251 210 405 370 620 1000 880 1290 1980 840 1640 1490 2480 402045 164 267 223 430 395 660 1060 930 1370 2030 890 1740 1580 2630 426050 173 280 235 455 415 690 1120 980 1440
40、2140 940 1830 1670 2780 449060 190 310 260 500 455 760 1230 1080 1580 2340 1030 2010 1830 3040 492070 205 350 280 525 490 810 1280 1140 1710 2530 1110 2170 1970 3280 5310AValues in mm are obtained by multiplying 25.38 mm/in. Values in Lpm are obtained by multiplying 3.785 L/gal.D 5716 95 (2006)3Valu
41、es of C may be obtained from Fig. 2, and Eq 3 may beused to calculate the pumping rate for any combination oforifice diameter, approach-pipe diameter, and water height inthe piezometer tube. The pumping rate, Q, will be in the unitsof gallons (litres) per minute when the orifice area, A,isinsquare i
42、nches (millimetres) and the water level in the manom-eter, h, is in inches (millimetres). The value of C from Fig. 2 isonly valid for use with this combination of units.8.4 A discharge of 55 gpm (208 Lpm) will cause 5 in. (127mm) of head due to a 212-in. (63.5 mm) orifice and a 4-in. (102mm) approac
43、h pipe. Similarly, a discharge of 5 310 gal (20.100L) per minute will cause 70 in. (1.780 mm) of head due to a12-in. (305 mm) orifice and a 16-in. (406 mm) approach pipe.8.5 Extensive calibrations of circular orifice weirs indicatedthat they will measure the flow through the orifice within 3 %of the
44、 true value when properly constructed and used.2 ,39. Report9.1 Record pertinent information, including orifice and pipesizes and manometer reading, time of reading, and welldischarge rate.9.2 Describe the physical features of the apparatus and anyunusual aspect of the measurements.10. Precision and
45、 Bias10.1 PrecisionDue to the nature of this test method it iseither not feasible or too costly at this time to develop a validprecision statement. Subcommittee D18.21 welcomes propos-als that would allow for development of a valid precisionstatement.10.2 BiasThere is no accepted reference value for
46、 this testmethod, therefore, bias cannot be determined.11. Keywords11.1 aquifers; aquifer test methods; discharge rate; groundwater; orifice weirFIG. 2 The Coefficient of Discharge, C, in the Orifice-Weir Equation3D 5716 95 (2006)4ASTM International takes no position respecting the validity of any p
47、atent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revisi
48、on at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your co
49、mments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610
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