ISO TR 15377-2007 Measurement of fluid flow by means of pressure-differential devices - Guidelines for the specification of orifice plates nozzles and Venturi t.pdf

1、 Reference number ISO/TR 15377:2007(E) ISO 2007TECHNICAL REPORT ISO/TR 15377 Second edition 2007-02-01 Measurement of fluid flow by means of pressure-differential devices Guidelines for the specification of orifice plates, nozzles and Venturi tubes beyond the scope of ISO 5167 Mesurage du dbit des f

2、luides au moyen dappareils dprimognes Lignes directrices pour la spcification des diaphragmes, des tuyres et des tubes Venturi non couverts par lISO 5167 ISO/TR 15377:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be pri

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5、s suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2007 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or

6、by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-

7、mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights reservedISO/TR 15377:2007(E) ISO 2007 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Symbols . 1 5 Square-edged orifice plates and nozzles: Wit

8、h drain holes, in pipes below 50 mm diameter, and as inlet and outlet devices 3 5.1 Drain holes through the upstream face of the square-edged orifice plate or nozzle 3 5.2 Square-edged orifice plates installed in pipes of diameter 25 mm u D 50 mm 4 5.3 No upstream or downstream pipeline 5 6 Orifice

9、plates (except square-edged) 8 6.1 Conical entrance orifice plates 8 6.2 Quarter-circle orifice plates . 12 6.3 Eccentric orifice plates. 18 7 Venturi tubes with machined convergent of angle 10,5 23 7.1 General. 23 7.2 Description 23 7.3 Limits of use 23 7.4 Discharge coefficient 24 7.5 Expansibilit

10、y expansion factor . 24 7.6 Pressure loss 24 7.7 Installation requirements . 24 Bibliography . 26 ISO/TR 15377:2007(E) iv ISO 2007 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work

11、 of preparing 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-governmen

12、tal, in 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 ma

13、in task 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. In

14、 exceptional circumstances, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example), it may decide by a simple majority vote of its participating members to publish a Technical Report. A Te

15、chnical Report is entirely informative in nature and does not have to be reviewed until the data it provides are considered to be no longer valid or useful. Attention 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 res

16、ponsible for identifying any or all such patent rights. ISO/TR 15377 was prepared by Technical Committee ISO/TC 30, Measurement of fluid flow in closed conduits, Subcommittee SC 2, Pressure differential devices. This second edition cancels and replaces the first edition (ISO/TR 15377:1998), which ha

17、s been technically revised. It incorporates Technical Corrigendum ISO/TR 15377:1998/Cor.1:1999. TECHNICAL REPORT ISO/TR 15377:2007(E) ISO 2007 All rights reserved 1 Measurement of fluid flow by means of pressure-differential devices Guidelines for the specification of orifice plates, nozzles and Ven

18、turi tubes beyond the scope of ISO 5167 1 Scope This Technical Report describes the geometry and method of use for conical-entrance orifice plates, quarter- circle orifice plates, eccentric orifice plates and Venturi tubes with 10,5 convergent angles. Recommendations are also given for square-edged

19、orifice plates and nozzles under conditions outside the scope of ISO 5167. NOTE The data on which this report is based are old or incomplete in some cases. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the

20、 edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 4006, Measurement of fluid flow in closed conduits Vocabulary and symbols ISO 5167-1:2003, Measurement of fluid flow by means of pressure differential devices inserte

21、d in circular cross-section conduits running full Part 1: General principles and requirements 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 4006 and ISO 5167-1 apply. 4 Symbols For the purposes of this document, the symbols given in Table 1 apply.

22、ISO/TR 15377:2007(E) 2 ISO 2007 All rights reservedTable 1 Symbols Symbols Represented quantity Dimensions M: mass L: length T: time SI unit a Pressure-tapping hole diameter L m C Discharge coefficient dimensionless d Diameter of orifice or throat of primary device at operating conditions L m D Upst

23、ream internal pipe diameter at operating conditions L m d tapDiameter of pressure tappings L m e Thickness of bore L m E, E 1Thickness of orifice plate L m F ECorrection factor dimensionless k Uniform equivalent roughness L m p Static pressure of the fluid ML 1T 2Pa q mMass flowrate MT 1kg/s r Radiu

24、s of profile L m R aArithmetical mean deviation of the (roughness) profile L m Re Reynolds number dimensionless Re D ,Re dReynolds number referred to D or d dimensionless Re* Throat-tapping Reynolds number ( = d tapRe d /d) dimensionless Diameter ratio, = d Ddimensionless p Differential pressure ML

25、1T 2Pa Expansibility (expansion) factor dimensionless Isentropic exponent dimensionless Friction factor dimensionless Mass density of the fluid ML 3kg/m 3 Pressure ratio, 2 1 p p = dimensionless NOTE 1 Other symbols used in this Technical Report are defined at their place of use. NOTE 2 Subscript 1

26、refers to the cross-section at the plane of the upstream pressure tapping. Subscript 2 refers to the cross-section at the plane of the downstream pressure tapping. ISO/TR 15377:2007(E) ISO 2007 All rights reserved 3 5 Square-edged orifice plates and nozzles: With drain holes, in pipes below 50 mm di

27、ameter, and as inlet and outlet devices 5.1 Drain holes through the upstream face of the square-edged orifice plate or nozzle 5.1.1 General Square-edged orifice plates and nozzles with drain holes may be used, installed and manufactured in accordance with the following guidelines. 5.1.2 Square-edged

28、 orifice plates If a drain hole is drilled through the orifice plate, the coefficient values specified in ISO 5167-2 should not be used unless the following conditions are observed. a) D should be larger than 100 mm. b) The diameter of the drain hole should not exceed 0,1d and no part of the hole sh

29、ould lie within a circle, concentric with the orifice, of diameter (D 0,2d). The outer edge of the drain hole should be as close to the pipe wall as practicable. c) The drain hole should be deburred and the upstream edge should be sharp. d) Single pressure tappings should be orientated so that they

30、are between 90 and 180 to the position of the drain hole. e) The measured orifice diameter, d m , should be corrected to allow for the additional orifice area represented by the drain hole of diameter d k , as shown in the following equation: 2 k m m 10 , 5 5 d dd d =+ (1) NOTE This equation is base

31、d on the assumption that the value for C (1 4 ) 0,5for flow through the drain hole is 10 % greater than the value for flow through the orifice. When estimating the overall uncertainty of the flow measurement, the following additional percentage uncertainty should be added arithmetically to the disch

32、arge coefficient percentage uncertainty: 2 k m 55 d d (2) 5.1.3 ISA 1932 nozzles If a drain hole is drilled through the nozzle upstream face, the coefficient values specified in ISO 5167-3 should not be used unless the following conditions are observed. a) The value of should be less than 0,625. b)

33、The diameter of the drain hole should not exceed 0,1d and no part of the hole should lie within a circle, concentric with the throat, of diameter (D 0,2d). c) The length of the drain hole should not exceed 0,1D. d) The drain hole should be deburred and the upstream edge should be sharp. ISO/TR 15377

34、2007(E) 4 ISO 2007 All rights reservede) Single pressure tappings should be orientated so that they are between 90 and 180 to the position of the drain hole. f) The measured diameter, d m , should be corrected to allow for the additional throat area represented by the drain hole of diameter d k , a

35、s shown in the following equation: 2 k m m 10 , 4 0 d dd d =+ (3) NOTE This equation is based on the assumption that the value for C (1 4 ) 0,5for flow through the drain hole is 20 % less than the value for flow through the throat of the nozzle. When estimating the overall uncertainty of the flow me

36、asurement, the following additional percentage uncertainty should be added arithmetically to the discharge coefficient percentage uncertainty: 2 k m 40 d d (4) 5.1.4 Long radius nozzles Drain holes through these primary elements should not be used. 5.2 Square-edged orifice plates installed in pipes

37、of diameter 25 mm u D 50 mm 5.2.1 General Orifice plates should be installed and manufactured in accordance with ISO 5167-2. 5.2.2 Limits of use When square-edged orifice plates are installed in pipes of bore 25 mm to 50 mm, the following conditions should be strictly observed. a) The pipes should h

38、ave high-quality internal surfaces such as drawn copper or brass tubes, glass or plastic pipes or drawn or fine-machined steel tubes. The steel tubes should be of stainless steel for use with corrosive fluids such as water. The roughness should be in accordance with ISO 5167-2:2003, 5.3.1. b) Corner

39、 tappings should be used, preferably of the carrier ring type detailed in ISO 5167-2:2003, Figure 4 a). c) The diameter ratio, , should be within the range 0,5 u u0,7. NOTE It is possible to have 0,23 u 0,5, but the uncertainty increases significantly if d 12,5 mm. 5.2.3 Discharge coefficients and c

40、orresponding uncertainties The Reader-Harris/Gallagher equation 1for corner tappings given in 5.3.2.1 of ISO 5167-2:2003 should be used for deriving the discharge coefficients, provided the pipe Reynolds numbers are within the limits given in ISO 5167-2:2003, 5.3.1. An additional uncertainty of 0,5

41、 should be added arithmetically to the uncertainty derived from 5.3.3.1 of ISO 5167-2:2003. ISO/TR 15377:2007(E) ISO 2007 All rights reserved 5 5.3 No upstream or downstream pipeline 5.3.1 General This clause should apply where there is no pipeline on either the upstream or the downstream side of t

42、he device or on both the upstream and the downstream sides of the device, that is for flow from a large space into a pipe or vice versa, or flow through a device installed in the partition wall between two large spaces. 5.3.2 Flow from a large space (no upstream pipeline) into a pipeline or another

43、large space 5.3.2.1 Upstream and downstream tappings The space on the upstream side of the device should be considered large if a) there is no wall closer than 4d to the axis of the device or to the plane of the upstream face of the orifice or nozzle, b) the velocity of the fluid at any point more t

44、han 4d from the device is less than 3 % of the velocity in the orifice or throat, and c) the diameter of the downstream pipeline is not less than 2d. NOTE 1 The first condition implies, for example, that an upstream pipeline of diameter greater than 8d (that is where d 6 mm, but the uncertainty incr

45、eases significantly if d 12,5 mm. ISO/TR 15377:2007(E) 6 ISO 2007 All rights reservedNOTE 2 Provided that u 0,2 and d W 12,5 mm, the Reader-Harris/Gallagher (1998) equation given in 5.3.2.1 of ISO 5167-2:2003 can be used in a pipeline for Re dW 3 500 with an uncertainty on the value of the discharge

46、 coefficient, C, of 1 % (if Re D0,75: 1/ 2 1 1 0,351 1 p p = (6) When p/p 1and are assumed to be known without error, the relative uncertainty of the value of e is equal to 1 3, 5 p p %. Test results for the determination of are known for air, steam and natural gas only. However, there is no known o

47、bjection to using the same formula for other gases and vapours whose isentropic exponent is known. 5.3.2.3 ISA 1932 nozzles 5.3.2.3.1 ISA 1932 nozzles should be manufactured in accordance with 5.1 of ISO 5167-3:2003. 5.3.2.3.2 The limits of use for ISA 1932 nozzles where there is flow from a large s

48、pace should be as follows: d W 11,5 mm; downstream there is either a large space or a pipeline whose diameter is not less than 2d; Re dW 100 000. 5.3.2.3.3 The discharge coefficient, C, is equal to 0,99. The uncertainty in the value of C is expected to be no better than 1 %. 5.3.2.3.4 The expansibil

49、ity factor, , is given by the following equation and is only applicable if p 2 /p 1W 0,75: 0,5 () / 1 11 = 2 -1(7) The relative uncertainty of the value of is equal to 2 p/p 1%. 5.3.2.4 Venturi nozzle 5.3.2.4.1 Venturi nozzles should be manufactured in accordance with 5.3 of ISO 5167-3:2003. ISO/TR 15377: