BS-ISO-3846-2008.pdf
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1、BRITISH STANDARD BS ISO 3846:2008 Hydrometry Open channel flow measurement using rectangular broad-crested weirs ICS 17.120.20 ? Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:01:54 MDTNo
2、reproduction or networking permitted without license from IHS -,-,- BS ISO 3846:2008 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2008 BSI 2008 ISBN 978 0 580 55992 1 National foreword This British Standard is the UK implementatio
3、n of ISO 3846:2008. It supersedes BS 3680-4E:1990 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee CPI/113, Hydrometry, to Subcommittee CPI/113/2, Notches, weirs and flumes. A list of organizations represented on this committee can be obtained on reque
4、st to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments/corrigenda issued since publication DateCommen
5、ts Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:01:54 MDTNo reproduction or networking permitted without license from IHS -,-,- Reference number ISO 3846:2008(E) INTERNATIONAL STANDARD I
6、SO 3846 Third edition 2008-02-15 Hydrometry Open channel flow measurement using rectangular broad-crested weirs Hydromtrie Mesure de dbit des liquides dans les canaux dcouverts au moyen de dversoirs rectangulaires seuil pais BS ISO 3846:2008 Copyright British Standards Institution Provided by IHS un
7、der license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:01:54 MDTNo reproduction or networking permitted without license from IHS -,-,- ii Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing C
8、o/5910770001 Not for Resale, 08/14/2008 22:01:54 MDTNo reproduction or networking permitted without license from IHS -,-,- iii Contents Page Foreword iv 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 1 4 Symbols. 1 5 Installation. 2 5.1 General. 2 5.2 Selection of site 2 5.3 Installa
9、tion conditions 3 6 General maintenance requirements 4 7 Measurement of head(s) 5 7.1 General. 5 7.2 Stilling or float well. 5 7.3 Zero setting . 5 8 Rectangular broad-crested weirs 6 8.1 Specification for the standard weir. 6 8.2 Location of the head gauge section . 7 8.3 Provision for modular flow
10、 7 9 Discharge relationships. 7 9.1 Modular flow discharge equation 7 9.2 Modular coefficient of discharge 7 9.3 Limitations for operation in the modular flow range 10 9.4 Drowned flow discharge equation 10 9.5 Limitations for operation in the drowned flow range 10 10 Uncertainties in flow measureme
11、nt 11 10.1 General. 11 10.2 Statement of the uncertainty of a flow measurement in a channel. 11 10.3 Combining measurement uncertainties. 12 10.4 Uncertainty of discharge coefficient u(C) for the broad-crested weir. 13 10.5 Uncertainty budget. 13 11 Example . 13 11.1 General. 13 11.2 Characteristics
12、 Gauging structure. 14 11.3 Characteristics Gauged head instrumentation. 14 11.4 The discharge coefficient 14 11.5 The discharge estimate 14 11.6 Uncertainty statement 15 Annex A (informative) Modular limit. 17 Annex B (informative) Gauged head discharge coefficient and total head discharge coeffici
13、ent 18 Annex C (informative) Introduction to measurement uncertainty. 19 Annex D (informative) Sample measurement performance for use in hydrometric worked examples 26 Bibliography. 28 BS ISO 3846:2008 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy
14、 Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 22:01:54 MDTNo reproduction or networking permitted without license from IHS -,-,- iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of pr
15、eparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, i
16、n liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main tas
17、k of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attentio
18、n is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 3846 was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 2, Flow measurement stru
19、ctures. This third edition cancels and replaces the second edition (ISO 3846:1989), of which it constitutes a technical revision. BS ISO 3846:2008 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/20
20、08 22:01:54 MDTNo reproduction or networking permitted without license from IHS -,-,- 1 Hydrometry Open channel flow measurement using rectangular broad-crested weirs 1 Scope This International Standard lays down requirements for the use of rectangular broad-crested weirs for the accurate measuremen
21、t of flow of clear water in open channels under free flow conditions. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced d
22、ocument (including any amendments) applies. ISO 772, Hydrometry Vocabulary and symbols 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 772 apply. 4 Symbols A m2 area of approach channel b m width of weir crest perpendicular to flow direction C discha
23、rge coefficient (gauged head) f drowned flow reduction factor fC combined coefficient of discharge Cd discharge coefficient (total head) Cv coefficient of velocity E m encoder height from datum eb m random uncertainty in the width measurement g m/s2 acceleration due to gravity H m total head above c
24、rest level h m gauged head above crest level (upstream head is inferred if no subscript is used) L m length of weir in the direction of flow n number of measurements in a set p m height of weir (difference between mean bed level and crest level) BS ISO 3846:2008 Copyright British Standards Instituti
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