1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 306 : 1997 The Euro
2、pean Standard EN 306 : 1997 has the status of a British Standard ICS 27.060.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Heat exchangers Methods of measuring the parameters necessary for establishing the performanceBS EN 306 : 1997 This British Standard, having been prep
3、ared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 October 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference RHE/30 Draft for comment ENV 306 DC ISBN 0 580 27
4、983 9 Amendments issued since publication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee RHE/30, Heat exchangers, upon which the following bodies were represented: British Refrigeration Associ
5、ation Building Services Research and Information Association Federation of Environmental Trade Associations HEVAC Association Waterheater Manufacturers Association BSI 1997 i BS EN 306 : 1997 National foreword This British Standard has been prepared by Technical Committee RHE/30, and is the English
6、language version of EN 306 : 1997 Heat exchangers Methods of measuring the parameters necessary for establishing the performance, published by the European Committee for Standardization (CEN). Cross-references Publication referred to Corresponding British Standard EN ISO 9000 BS EN ISO 9000 Quality
7、management and quality assurance standards BS EN ISO 5167 Measurement of fluid flow by means of differential pressure ISO 5167 Part 1 : 1997 Orifice plates, nozzles, and venturi tubes inserted in circular cross-section conduits running full Compliance with a British Standard does not of itself confe
8、r immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 26, an inside back cover and a back cover.ii blankCEN European Committee for Standardization Comite Europe en de Normalisation Europa isches
9、 Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1997 Copyright reserved to CEN members. Ref. No. EN 306 : 1997 E EUROPEAN STANDARD EN 306 NORME EUROPE ENNE EUROPA ISCHE NORM February 1997 ICS 27.060.30 Supersedes ENV 306 : 1990 Descriptors: Heat transfer, heat exchange
10、rs, definitions, thermodynamic properties, measurements, flow measurements, pressure measurements, temperature measurements English version Heat exchangers Methods of measuring the parameters necessary for establishing the performance Echangeurs thermiques Me thodes de mesurage des parame tres ne ce
11、ssaires a le valuation des performances Wa rmeaustauscher Messungen und Messgenauigkeit bei der Leistungsbestimmung This European Standard was approved by CEN on 1997-01-10. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this Europ
12、ean 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 CEN 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 CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finla
14、nd, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 306 : 1997 BSI 1997 Foreword This European Standard has been prepared by Technical Committee CEN/TC110, Heat Exchangers, the secretariat of which i
15、s held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by August 1997, and conflicting national standards shall be withdrawn at the latest by August 1997. The Document was implemented previou
16、sly as a European Prestandard (ENV) in 1990 and no technical changes have been made. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany,
17、Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Contents Page Foreword 2 Introduction 4 1 Scope 4 2 Normative references 4 3 Definitions 4 3.1 Measurement of temperature 4 3.2 Measurement of flow-rate 4 3.3 Measurement of
18、 pressure 5 3.4 Meausurement of fluid quality 6 3.5 General definitions 6 4 Sampling 7 4.1 Sampling frequency 7 4.2 Measuring sampling period 7 4.3 Simultaneous reading of measurement 7 4.4 Mean value calculation 7 5 Temperature measurement 7 5.1 Purpose 7 5.2 Equipment 7 5.2.1 Expansion thermometer
19、s 7 5.2.2 Resistance thermometers 8 5.2.3 Thermocouples 8 5.3 Preparations 8 5.3.1 Installation 8 5.3.2 Location 9 5.3.3 Static measurement error 9 5.3.4 Dynamic measurement error 10 5.3.5 Other requirements for temperature sensor installation 10 Page 5.4 Calibration 11 5.4.1 Purpose 11 5.4.2 Tracea
20、bility 11 5.4.3 Uncertainty of calibration 11 5.4.4 Calibration interval 11 5.5 Stability 11 5.6 Presentation of temperature measurement 11 6 Measurement of flow-rate 12 6.1 Purpose 12 6.2 Equipment 12 6.2.1 Common measuring methods for liquids and gas 12 6.2.2 Measurement methods for liquid flow-ra
21、tes 14 6.2.3 Measurement of two-phase flow 15 6.3 Preparations 15 6.3.1 Installation 15 6.3.2 Location 15 6.3.3 Static measurement error 16 6.3.4 Dynamic measurement error 16 6.3.5 Other requirements for flow meter installation 16 6.4 Calibration 16 6.4.1 Purpose 16 6.4.2 Traceability 16 6.4.3 Uncer
22、tainty of calibration 17 6.4.4 Calibration interval 17 6.5 Stability 17 6.6 Presentation of mass flow measurement 17 7 Measurement of pressure 18 7.1 Purpose 18 7.2 Measurement probes and pressure tappings 18 7.2.1 Total pressure 18 7.2.2 Static pressure 18 7.2.3 Dynamic pressure 18 7.2.4 Pressure d
23、rop 18 7.3 Equipment 18 7.3.1 U-tube manometer 20 7.3.2 Pressure transducer 20 7.4 Preparations 20 7.4.1 Installation 20 7.4.2 Location 20 7.4.3 Static measuring error 20 7.4.4 Dynamic measuring errors 20 7.4.5 Other requirements for pressure tapping installation 22Page 3 EN 306 : 1997 BSI 1997 Page
24、 7.5 Calibration 22 7.5.1 Purpose 22 7.5.2 Traceability 22 7.5.3 Uncertainty of calibration 22 7.5.4 Calibration interval 22 7.6 Stability 23 7.7 Presentation of pressure measurement 23 8 Fluid quality 23 8.1 Purpose 23 8.2 Determination of density 24 8.3 Determination of specific heat capacity/enth
25、alpy 24 8.4 Determination of vapour ratio, (x) 24 8.5 Determination of phase state 24 8.6 Determination of viscosity 24 8.7 Determination of mass ratios 24 9 Requirements for peripheral equipment and media 24 9.1 Peripheral equipment 24 9.1.1 Regulating system 24 9.1.2 Heaters and coolers 24 9.1.3 F
26、lows 24 9.1.4 Pressures 24 9.2 Media 25 9.2.1 Ageing 25 9.2.2 Filtering 25 10 Test record 25 10.1 Laboratory test and acceptance test 25Page 4 EN 306 : 1997 BSI 1997 Introduction This European Standard is one of a series of European Standards dedicated to heat exchangers. If a performance measuremen
27、t of a heat exchanger is to be meaningful it is necessary to measure with well-known instruments, transducers and methods. The standard deals with different instruments, transducers and methods for measuring temperatures, flow-rates, pressures and fluid quality for heat exchangers. 1 Scope This Euro
28、pean Standard specifies the methods and accuracy of measurement for temperature, pressure, fluid quality and massflow of different fluids and how to determine the pressure drops across a heat exchanger. Measurements are restricted to those necessary for establishing the performance of heat exchanger
29、s classified in prEN 247 using the fluids listed in prEN 247. This European Standard applies when reference by the various branch application standards. The specific application European Standards shall be the prime reference documents. 2 Normative references This European Standard incorporates by d
30、ated or undated references, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standa
31、rd only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. prEN 247 Heat exchangers Terminology prEN 305 Heat exchangers Definitions of performance of heat exchangers and the general test procedure for establishing perf
32、ormance of all heat exchangers prEN 307 Heat exchangers Guidelines to prepare instructions required to maintain the performance of each type of heat exchanger EN ISO 9000 Quality management and quality assurance standards ISO 2186 Fluid flow in closed circuits Connections for pressure signal transmi
33、ssion between primary and secondary elements ISO 5167-1 Measurement of fluid flow by means of pressure differential devices Part 1: Orifice plates, nozzles and Venturi tubes inserted in circular cross conduits running full ISO 5221 Air distribution and air diffusion Rules to methods of measuring air
34、 flow rate in an air handling duct 3 Definitions For the purposes of this European Standard, the following definitions apply. 3.1 Measurement of temperature 3.1.1 temperature A measurement of the average kinetic energy of fluid particles due to their random motion in a fluid in thermodynamic equilib
35、rium 3.1.2 total temperature Fluid temperature including the temperature rise at a point of stagnation in a fluid flow. 3.1.3 inlet temperature The average total temperature at the standard inlet point of a heat exchanger. 3.1.4 outlet temperature The average total temperature at the standard outlet
36、 point of a heat exchanger. 3.1.5 working temperatures The inlet temperature on the primary and secondary sides respectively. 3.2 Measurement of flow-rate 3.2.1 flow rate of a fluid through a cross-section of a conduit The amount of fluid flowing through the cross-section of a conduit in unit time.
37、3.2.2 flowmeter A device for measuring the flow rate. 3.2.3 straight length A portion of a conduit whose axis is straight, and in which the cross-sectional area and cross-sectional shape are constant; the cross-sectional shape is usually circular. 3.2.4 fully-developed velocity distribution A veloci
38、ty distribution that does not change between two cross-sections of a flow. It is generally obtained after passing a sufficient straight length of a conduit. 3.2.5 regular velocity distribution The distribution of velocities which sufficiently approaches that established in a long straight length of
39、the closed conduit to permit an accurate measurement of the flow-rate to be made.Page 5 EN 306 : 1997 BSI 1997 1) The steady flows observed in conduits are in practice flows in which quantities such as velocity, pressure, mass density and temperature vary in time about mean values independent of tim
40、e; these are actually statistically steady flows 2) Two types of pulsating flow are found: periodic pulsating flow random pulsating flow 3) The time interval being considered is to be long enough to exclude from this definition the random components of the turbulent flow itself 4) For a circular con
41、duit running full, the hydraulic diameter is equal to the diameter of the conduit 5) Laminar flow may be unsteady but is completely free from turbulent mixing. Poiseuille flow is an example of steady laminar flow in a circular conduit 6) As a guide, the Reynolds number for the transition flow of a N
42、ewtonian fluid, when referred to the conduit diameter, is generally between a lower limit of 2 000 and upper limit which varies between 7 000 and 12 000 according to the conduit roughness and other factors 7) When specifying a Reynolds number, one should indicate the characteristic dimension on whic
43、h it has been based (for example diameter of the conduit, diameter of the differential pressure device, diameter of a Pitot tube head, etc.) 3.2.6 flow straightener a) Device inserted in a conduit to eliminate or reduce circumferential velocity components which produce swirl (swirl remover). b) Devi
44、ce inserted in a conduit to reduce the straight length required to achieve a regular velocity distribution (profile regulator). 3.2.7 steady flow 1) Flow in which the flow-rate through a measuring section does not vary significantly with time. 3.2.8 pulsating flow of mean constant flow-rate 2) Flow
45、in which the flow-rate in a measuring section is a function of time but has a constant mean value when averaged over a sufficiently long period of time. 3.2.9 unsteady flow 3) Flow in which the flow-rate in a measuring section fluctuates randomly with time. 3.2.10 hydraulic diameter 4) Four times th
46、e wetted cross-sectional area divided by the wetted perimeter. 3.2.11 laminar flow 5) Flow under conditions where forces due to viscosity are significant in comparison to the forces due to inertia. 3.2.12 turbulent flow Flow under conditions where forces due to viscosity are small in comparison to t
47、he forces due to inertia. 3.2.13 transition flow 6) Flow lying between a laminar flow and a turbulent flow. 3.2.14 Reynolds number 7) A dimensionless parameter expressing the ratio between the inertia and viscous forces. It is given by the formula R e = u:l V where: u is the average spatial fluid ve
48、locity expressed in metre per second; l is a characteristic dimension of the system in which the flow occurs expressed in metres; V is the kinematic viscosity of the fluid expressed in square metre per second. 3.3 Measurement of pressure 3.3.1 pressure Ratio of force and area. 3.3.2 static pressure
49、Pressure caused by the random motion of fluid particles. In fluid flows static pressure is determined in such a way that the flow does not affect the determination of static pressure. 3.3.3 dynamic pressure Pressure caused by the systematic motion of fluid particles in a fluid flow. 3.3.4 total pressure The sum of static pressure and dynamic pressure in a fluid flow (equivalent to the ratio of mechanical energy and volume). 3.3.5 stagnation pressure Sum of the static pressure and the dynamic pressure. It characterizes the state of
