BS EN 60534-2-5-2003 Industrial-process control valves - Flow capacity - Sizing equations for fluid flow through multistage control valves with interstage recovery《工业过程控制阀 流通能力 通过有.pdf

1、BRITISH STANDARD BS EN 60534-2-5:2003 Industrial-process control valves Part 2-5: Flow capacity Sizing equations for fluid flow through multistage control valves with interstage recovery The European Standard EN 60534-2-5:2003 has the status of a British Standard ICS 23.060.40; 25.040.40 BS EN 60534

2、-2-5:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 7 November 2003 BSI 7 November 2003 ISBN 0 580 42868 0 National foreword This British Standard is the official English language version of EN 60534-2-5:2003. It is identical with IEC 6

3、0534-2-5:2003. The UK participation in its preparation was entrusted by Technical Committee GEL/65, Measurement and control, to Subcommittee GEL/65/2, Elements of systems, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secr

4、etary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catal

5、ogue or of British Standards Online. 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 does not of itself confer immunity from legal obligations. aid enquirers to understand t

6、he text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an i

7、nside front cover, the EN title page, pages 2 to 28, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEAN STANDARD EN 60534-2-5 NORME EUROPENNE EUROPI

8、SCHE NORM October 2003 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2003 CENELEC - All rights of exploitation in any form and

9、 by any means reserved worldwide for CENELEC members. Ref. No. EN 60534-2-5:2003 E ICS 23.060.40 ; 25.040.40 English version Industrial-process control valves Part 2-5: Flow capacity Sizing equations for fluid flow through multistage control valves with interstage recovery (IEC 60534-2-5:2003) Vanne

10、s de rgulation des processus industriels Partie 2-5: Capacit dcoulement Equations de dimensionnement pour lcoulement des fluides dans les vannes de rgulation multi-tages avec rcupration entre tages (CEI 60534-2-5:2003) Stellventile fr die Prozessregelung Teil 2-5: Durchflusskapazitt Bemessungsgleich

11、ungen fr Fluide durch Mehrstufenregelventile mit Druckrckgewinn zwischen den Stufen (IEC 60534-2-5:2003) This European Standard was approved by CENELEC on 2003-10-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European

12、 Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English

13、, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Bel

14、gium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom. EN 63504-2-5:0230 - - 2 Foreword The text of document 65B/488/FDIS, future edition

15、1 of IEC 60534-2-5, prepared by SC 65B, Devices, of IEC TC 65, Industrial-process measurement and control, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60534-2-5 on 2003-10-01. The following dates were fixed: latest date by which the EN has to be implemented at na

16、tional level by publication of an identical national standard or by endorsement (dop) 2004-07-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2006-10-01 Annexes designated “normative“ are part of the body of the standard. Annexes designated “informat

17、ive“ are given for information only. In this standard, annex ZA is normative and annexes A and B are informative. Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60534-2-5:2003 was approved by CENELEC as a European Standard without any modification

18、. _ Page2 EN6053425:2003CONTENTS INTRODUCTION.4 1 Scope.5 2 Normative references.5 3 Terms and definitions .5 4 Installation7 5 Symbols.8 6 Sizing equations for incompressible fluids 9 6.1 Turbulent flow.9 7 Sizing equations for compressible fluids .10 7.1 Turbulent flow.11 8 Determination of correc

19、tion factors .12 8.1 Piping geometry factor, F p .12 8.2 Liquid pressure recovery factors F Lor F LP 12 8.3 Liquid critical pressure ratio factor F F 13 8.4 Expansion factor Y 13 8.5 Pressure differential ratio factor x Tor x TP 14 8.6 Specific heat ratio factor F .14 8.7 Compressibility factor Z.14

20、 8.8 Stage interaction factor k.15 8.9 Reheat factor r 15 Annex A (informative) Physical constants a .17 Annex B (informative) Examples of sizing calculations.18 Annex ZA (normative) Normative references to international publications with their corresponding European publiations .27 Bibliography28 F

21、igure 1 Multistage multipath trim 6 Figure 2 Multistage single path trim .7 Figure 3 Reference pipe section for sizing .8 Figure 4 Liquid critical pressure ratio factor F F .16 Table 1 Numerical constants N 15 Table 2 Typical values of liquid pressure recovery factor F L , and pressure differential

22、ratio factor x T at full rated travel .16 Table 3 Values of the stage interaction factors k and the reheat factors r.16 Page3 EN6053425:2003 INTRODUCTION This part of IEC 60534 includes equations for predicting flow which are the same as IEC 60534-2-1. The differences in this multistage standard are

23、: a) the equation for the calculation of expansion factor Y (equation 18); b) the non-inclusion of the section on sizing for laminar flow; c) the inclusion of stage interaction factor k (8.8) and reheat factor r (8.9); d) the addition of Tables for multistage valves for values of F Land x T.The test

24、 data used to validate the method for numbers of stages from one to five was obtained from sizing tests carried out in accordance with IEC 60534-2-3 using air as the test medium at pressures varying from 5 10 5Pa to 13,5 10 5Pa and at temperatures of approximately 300 K. Some data was obtained under

25、 plant conditions using steam at pressures varying from 12 10 5Pa to 110 10 5Pa and temperatures from 460 K to 750 K. The method is applicable to any number of stages but has only been validated up to five stages. If valve specific coefficients (such as K vor C v , F L , and x T ) cannot be determin

26、ed by appropriate test procedures in IEC 60534-2-3, values supplied by the manufacturer should then be used. Page4 EN6053425:2003INDUSTRIAL-PROCESS CONTROL VALVES Part 2-5: Flow capacity Sizing equations for fluid flow through multistage control valves with interstage recovery 1 Scope This part of I

27、EC 60534 includes equations for predicting the flow of compressible and incompressible fluids through multistage control valves. The equations for incompressible flow are based on standard hydrodynamic equations for Newtonian incompressible fluids. They are not intended for use when non-Newtonian fl

28、uids, fluid mixtures, slurries, or liquid-solid conveyance systems are encountered. At very low ratios of pressure differential to absolute inlet pressure ( p/p 1 ), compressible fluids behave similarly to incompressible fluids. Under such conditions, the sizing equations for compressible flow can b

29、e traced to the standard hydrodynamic equations for Newtonian incompressible fluids. However, increasing values of p/p 1result in compressibility effects which require that the basic equations be modified by appropriate correction factors. The equations for compressible fluids are for use with gas o

30、r vapour and are not intended for use with multiphase streams such as gas-liquid, vapour-liquid or gas-solid mixtures. This standard is applicable only to those designs of multistage multipath control valves and multistage single path control valves. 2 Normative references The following referenced d

31、ocuments 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 document (including any amendments) applies. IEC 60534-1:1987, Industrial-process control valves Part 1: Control valve t

32、erminology and general considerations IEC 60534-2-1:1998, Industrial-process control valves Part 2-1: Flow capacity Sizing equations for fluid flow under installed conditions IEC 60534-2-3:1997, Industrial-process control valves Part 2-3: Flow capacity Test procedures 3 Terms and definitions For the

33、 purposes of this document, the terms and definitions given in IEC 60534-1 and the following apply. Page5 EN6053425:20033.1 multistage control valves a globe control valve where the trim has several stages which are separated by a gap (see Figures 1 and 2). The geometrical contour of the apertures i

34、n all stages must be similar. The ratio of the second stage flow coefficient C to the first stage flow coefficient C must not exceed 1,80. The ratio of the flow coefficient C of the other stages to their previous stage must not exceed 1,55 and must be uniform within a tolerance of 9 %. Normally for

35、incompressible fluids the flow coefficients of the stages are approximately equal, a slightly smaller flow coefficient C being allocated to a particular stage only if it is required to take a higher pressure drop. 3.2 gap the distance between adjacent stages 3.3 multistage multipath control valves a

36、 globe control valve where the trim has multiple flow passages having several stages which are separated by a gap (see Figure 1). The gap should conform to the values calculated from the following equation with a tolerance of +15 % and 10 % (see Figures 1 and 2). Ds 589 , 1 1 travel rated at stage u

37、pstream adjacent of area hole total gap = lwhere the total hole area is in mm 2 ; l is the travel, in mm; Ds is the outside diameter of adjacent upstream stage, in mm; minimum gap limit = 4 mm; maximum gap limit = 44 mm. Gap IEC 2141/03NOTE This is one example of a multistage trim. Figure 1 Multista

38、ge multipath trim Page6 EN6053425:20033.4 multistage single path control valves a globe control valve where the trim has one flow passage having several stages which are separated by a gap (see Figure 2). The gap should be within the following minimum and maximum limits: minimum gap = 0,60 times the

39、 seat diameter of the previous stage; maximum gap = 1,10 times the seat diameter of the previous stage. Seat diameter Gap IEC 2142/03NOTE This is one example of a multistage trim. Figure 2 Multistage single path trim 4 Installation In applications for single stage valves, the influence of reducers a

40、nd other fittings may be significant. For multistage valves with C v /d 2 0,01 (K v /d 2 0,0086) they have virtually no effect. In sizing control valves, using the relationships presented herein, the flow coefficients calculated are assumed to include all head losses between points A and B, as shown

41、 in Figure 3. Page7 EN6053425:2003Flow Control valve with or without attached fittings A Pressure tap l 1 B l 2 Pressure tap IEC 2143/03Key l 1= two nominal pipe diameters l 2= six nominal pipe diameters Figure 3 Reference pipe section for sizing 5 Symbols Symbol Description Unit C Flow coefficient

42、(K v , C v ) Various (see IEC 60534-1) (see Note 3) C iAssumed flow coefficient for iterative purposes Various (see IEC 60534-1) (see Note 3) d Nominal valve size mm D Internal diameter of the piping mm D 1Internal diameter of upstream piping mm D 2Internal diameter of downstream piping mm D oOrific

43、e diameter mm F FLiquid critical pressure ratio factor 1 F LLiquid pressure recovery factor of a control valve without attached fittings 1 (see Note 3) F LPCombined liquid pressure recovery factor and piping geometry factor of a control valve with attached fittings 1 (see Note 3) F PPiping geometry

44、factor 1 F Specific heat ratio factor 1 k Stage interaction factor 1 M Molecular mass of flowing fluid kg/kmol N Numerical constants (see Table 1) Various (see Note 1) n Number of stages 1 p 1Inlet absolute static pressure measured at point A (see Figure 1) kPa or bar (see Note 2) p 2Outlet absolute

45、 static pressure measured at point B (see Figure 1) kPa or bar p cAbsolute thermodynamic critical pressure kPa or bar p rReduced pressure (p 1 /p c ) 1 p vAbsolute vapour pressure of the liquid at inlet temperature kPa or bar p Differential pressure between upstream and downstream pressure taps (p 1

46、 p 2 ) kPa or bar Q Volumetric flow rate (see Note 4) m 3 /h r Reheat factor 1 Page8 EN6053425:2003 Symbol Description Unit T 1Inlet absolute temperature K T cAbsolute thermodynamic critical temperature K T rReduced temperature (T 1 /T c ) 1 t sAbsolute reference temperature for standard cubic metre

47、 K W Mass flow rate kg/h x Ratio of pressure differential to inlet absolute pressure ( p/p 1 ) 1 x TPressure differential ratio factor of a control valve without attached fittings at choked flow 1 (see Note 3) x TPPressure differential ratio factor of a control valve with attached fittings at choked

48、 flow 1 (see Note 3) Y Expansion factor 1 Z Compressibility factor 1 1Density of fluid at p 1and T 1kg/m 3 1 / oRelative density ( 1 / o= 1,0 for water at 15 C) 1 Specific heat ratio 1 NOTE 1 To determine the units for the numerical constants, dimensional analysis may be performed on the appropriate

49、 equations using the units given in Table 1. NOTE 2 1 bar = 10 2 kPa = 10 5Pa NOTE 3 These values are travel-related and should be stated by the manufacturer. NOTE 4 Volumetric flow rates in m 3 /h, identified by the symbol Q, refer to standard conditions. The standard cubic metre is taken at 1013,25 mbar and either 273 K or 288 K (see Table 1). 6 Sizing equation