BS 5860-1980 Method for measuring the efficiency of hydraulic turbines storage pumps and pump-turbines (thermodynamic method)《水轮机、蓄水泵及涡轮泵的效率测定方法(热力学法)》.pdf

1、BRITISH STANDARD BS 5860:1980 IEC 607:1978 Method for Measuring the efficiency of hydraulic turbines, storage pumps and pump-turbines (thermodynamic method) IEC title: Thermodynamic method for measuring the efficiency of hydraulic turbines, storage pumps and pump-turbines UDC 621.224.018.1:532.083:5

2、31.61:536.72 + 621.65.004.15:532.083:531.61:536.72BS5860:1980 This British Standard, having been prepared under the directionof the Mechanical Engineering Standards Committee, was published underthe authority of the Executive Board and comes into effect on 29February1980 BSI 12-1999 The following BS

3、I references relate to the work on this standard: Committee reference MEE/125 Draft for comment 75/75334 ISBN 0 580 11126 1 Cooperating organizations The Mechanical Engineering Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the followi

4、ng Government departments and scientific and industrial organizations: The organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Associated Offices Technical Committee

5、Department of Trade (Marine Division) Association of Consulting Engineers* Department of Transport Association of Hydraulic Equipment Electricity Supply Industry in England and Manufacturers Wales* Association of Mining Electrical and Engineering Equipment Users Association Mechanical Engineers Fede

6、ration of Manufacturers of Construction British Compressed Air Society Equipment and Cranes British Electrical and Allied Manufacturers Health and Safety Executive Association (BEAMA) Institution of Gas Engineers British Gas Corporation Institution of Mechanical Engineer British Gear Manufacturers A

7、ssociation Institution of Plant Engineers British Internal Combustion Engine Institution of Production Engineers Manufacturers Association Lloyds Register of Shipping* British Pump Manufacturers Association London Transport Executive British Steel Corporation Machine Tool Industry Research Associati

8、on British Steel Industry Ministry of Defence British Valve Manufacturers Association Ltd National Coal Board Chartered Institution of Building Services Oil Companies Materials Association Crown Agents for Oversea Governments and Process Plant Association Administrations Society of Motor Manufacture

9、rs and Traders Department of the Environment Limited Department of Industry (Mechanical Telecommunication Engineering and Engineering) Manufacturing Association (TEMA) Department of Industry (National Engineering Water-tube Boilermakers Association Laboratory)* Institution of Civil Engineers North o

10、f Scotland Hydro-electric Board Institution of Electrical Engineers Power Generation Association (BEAMA) Amendments issued since publication Amd. No. Date of issue CommentsBS5860:1980 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii 1 Object and scope 1 1

11、.1 Purpose of the standard 1 1.2 Excluded topics and limitations 1 1.3 Principle 1 2 Terms, definitions, symbols, units 2 3 Procedure for measurement of mechanical energy per unit mass 4 3.1 General 4 3.2 “Direct” operating procedure 5 3.3 “Partial expansion” operating procedure 5 3.4 Expansion proc

12、edure for thermometer calibration 5 4 Determination of hydraulic energy per unit mass 6 5 Apparatus 6 5.1 Main measurements 6 5.2 Auxiliary measurements 8 6 Conditions for taking measurement Corrective terms 8 6.1 Measuring sections and “sampling” conditions 8 6.2 Particular flow arrangements 9 6.3

13、Instability of total energy at inlet 9 6.4 Extraneous exchanges 10 6.5 Limitation of corrections 11 6.6 Unfavourable conditions for some systems 11 7 Precision of measurements 11 7.1 Estimation of error due to determination of the main terms 12 7.2 Estimation of error in corrections due to secondary

14、 phenomena 13 7.3 Errors due to faulty exploration of flow distribution 13 Comments on the origin of the values for the thermodynamic properties of water 14 Figure 1 General schematic diagram of measuring vessels 4 Figure 2 Example of graphic determination of the correction in e mto allow for heat t

15、ransfer 7 Table I Values of the volume of water per unit mass v 15 Table II Values of the isothermal factor a 15 Table III Values for heat per unit mass c p21 f m e () 1 f m e () 2 f m e () 3BS5860:1980 ii BSI 12-1999 National foreword This British Standard was prepared under the direction of the Me

16、chanical Engineering Standards Committee and is identical with IEC Publication607 “Thermodynamic method for measuring the efficiency of hydraulic turbines, storage pumps and pump-turbines” published in1978 by the International Electrotechnical Commission (IEC). Terminology and conventions. The text

17、of the International Standard has been approved as suitable for publication, without deviation, as a British Standard. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following: The comma has been used in tables as

18、 a decimal marker. In British Standards it is current practice to use a full point on the baseline as a decimal marker. In the titles of Table I, Table II and Table III unit symbols have been printed in italic (sloping) type instead of roman (upright) type as required by convention (as described in

19、BS 0 “A standard for standards” Part4 “BSI editorial practice”). Cross-references. There are no British Standard equivalents for IEC41and IEC198 to which references are made in clause 4 and 6.1. The technical committee has reviewed their provisions, and has decided that they are acceptable for use i

20、n conjunction with this standard. NOTETextual error. When adopting the text of the International Standard, the errors listed below were noticed. They have been corrected in this British Standard and have been reported to IEC in a proposal to amend the text of the International Standard. In 2.6 Press

21、ure, in the unit column, P ahas been deleted and replaced by Pa. In 2.7 Mass per unit area, in the definition column, has been deleted and replaced by . A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their cor

22、rect application. Compliance with a British Standard does not of itself confer immunity from legal obligations. 1 p - 1 - Summary of pages This document comprises a front cover, an inside front cover, pagesiandii, pages1to23 and a back cover. This standard has been updated (see copyright date) and m

23、ay have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS5860:1980 BSI 12-1999 1 1 Object and scope 1.1 Purpose of the standard This standard serves as a basis for the measurements to be made on hydraulic turbines, storage pumps and pump-turbines

24、 and for the computation of their efficiency applying the thermodynamic method. This method is based on the evaluation of the energy per unit mass of water delivered to a turbine shaft or received by water from a pump shaft. It may be determined by measurements of the performance variables (pressure

25、, temperature, velocity and level) and from the thermodynamic properties of water. This standard may be used for acceptance tests or for any other efficiency test. 1.2 Excluded topics and limitations Technological aspects of instrumentation have been dealt with in a general way taking into account t

26、he fact that the apparatus presently available varies widely and may possibly become obsolete in the future. The only requirements of instruments are to satisfy conditions stipulated in this standard (accuracy, heat exchange, etc.). Due to the lack of uniformity in values measured at the inlet and o

27、utlet sections of the machines, the limitations of measuring equipment and the relatively high magnitude of the corrective terms originating from the imperfect measuring conditions, the scope of this method is limited and it can only be used for heads in excess of100m. However, under highly favourab

28、le conditions, the range could be extended to cover lower heads subject to an analysis of the accuracy of the measurements. 1.3 Principle The thermodynamic method results from the application of the principle of conservation of energy (first law of thermodynamics) to a transfer of energy between wat

29、er and the machine through which it is flowing. In the case of actual machine operation, the energy per unit mass delivered to a turbine shaft or received by water from a pump shaft may be determined by measurement of the performance variables (pressure, temperature, velocity and level) and from the

30、 thermodynamic properties of water. This exchange of energy will be referred to as “mechanical energy per unit mass” (see Sub-clause 2.2 and Clause3). In the case of ideal operation, i.e. frictionless flow (assuming identical pressures at the inlet and at the outlet and an identical temperature at t

31、he inlet as in actual operation), the same application can be used for calculating the ideal energy per unit mass delivered to a turbine shaft or received from a pump shaft. Such energy is dependent solely upon the properties of the water and the characteristics of the hydroelectric plant. It is ref

32、erred to as “hydraulic energy per unit mass” (see Sub-Clause 2.1 and Clause4). The need to measure mass rate of flow is eliminated by using the two values of energy per unit mass calculated as above. The above principle presupposes that all losses in hydraulic machines are dissipated in the flow. In

33、 actual operation, friction losses in the bearings may be dissipated differently. In this case, a corresponding correction is made to mechanical energy per unit mass (see Sub-Clause2.4).BS5860:1980 2 BSI 12-1999 2 Terms, definitions, symbols, units Term Definition Symbol Unit 2.1 Hydraulic energy pe

34、r unit mass a The energy per unit mass delivered to a turbine shaft or received from a pump shaft in the case of ideal machine operation e h J kg 1 The measurement points for determining e hare marked: 1, 2, etc. (seeFigure 1, page 4) 2.2 Mechanical energy per unit mass a The energy per unit mass de

35、livered to a turbine shaft or received from a pump shaft in the case of actual operation The measurement points for determining e mare marked: 1, 1 1, 1 2, 2 1, etc. (see Figure 1) e m J kg 1 2.3 Corrective term for energy due to secondary phenomena %e mis calculated according to the recommendations

36、 given in Clause 6 %e m J kg 1 2.4 Energy per unit mass corresponding to contractual losses Energy per unit mass corresponding to contractual losses in the hydraulic machine which are not removed by water between the measuring sections (e.g. losses through bearings, where applicable) e x J kg 1 2.5

37、Machine efficiency For a turbine: For a pump: 2.6 Pressure Pressure above atmospheric pressure p Pa a Use of the term “energy per unit mass” is considered to be preferable to “energy per unit weight” because it offers a more general meaning. Nevertheless, energy per unit weight (i.e. specific head f

38、or the installation considered) can be used as a basis. Conversion of numerical values expressing energy per unit mass into head is ensured by dividing the former by , the mean value for acceleration due to gravity between the extreme levels of the installation. gBS5860:1980 BSI 12-1999 3 Term Defin

39、ition Symbol Unit 2.7 Volume per unit mass a (Volume per unit of mass = ) v m 3 kg 1 2.8 Temperature T C 2.9 Isothermal factor b Factor characterizing a thermodynamic property of water a m 3 kg 1 2.10 Specific heat c Specific heat at constant pressure c p J kg 1 C 1 2.11 Mean value of a d Values of

40、a and c pcorresponding to: the mean value where: m 3 kg 1 and 2.12 Mean value of c p d the mean value where: J kg 1 C 1 2.13 Mean value of v d Value of v corresponding to T 1and the mean value where: m 3 kg1 2.14 Water velocity V m s 1 2.15 Measuring point level z m 2.16 Shaft power Shaft power corr

41、esponding to mechanical energy per unit mass P m W 2.17 Volume-flow Volume-flow of water turbined or pumped past a certain point Q m 3 s 1 2.18 Density Mass per unit volume kg m 3 2.19 Acceleration due to gravity Acceleration due to gravity, at the point considered and at plant level g m s 2 a Value

42、s for v are given in Table I, page 15. b Values for a are given in Table II, page 18. c Values for c p are given in Table III, page 21. d Fractional error in e mand e hattributable to the adoption of mean values , andinstead of exact integrals (for pressures between 0 and 150 bar and temperatures be

43、tween 0 and 30 C) does not exceed 0.5 10 4 . 1 - p a T c p p v = 1 v - a v c pBS5860:1980 4 BSI 12-1999 3 Procedure for measurement of mechanical energy per unit mass 3.1 General Due to the difficulties inherent in measuring directly in the flow, quantities defining e mmust be measured in specially

44、designed vessels with tappings for determination of temperature and pressure (see Sub-clause5.1.1). When the measuring sections are under pressure, the procedure consists of extracting a sample flow, generally of between0.1dm 3 /s and0.5dm 3 /s, by a total head probe. The water thus extracted is led

45、 to the measuring vessel through an insulated pipe to ensure that the heat exchange with the exterior, estimated in accordance with the procedure detailed in Sub-clause5.1.1, does not exceed the limit fixed in Sub-clause6.5. This “sampling” is valid if the recommendations given in Sub-clause6.1 rega

46、rding extraction points are followed. For the general case where the turbine outlet is at atmospheric pressure, a specially designed measuring device is placed directly in the tail-race. The and g z terms are of minor importance and their determination calls for no particular remarks. It should be n

47、oted that levels z 1 1and z 2 1are those of the middle points of the measuring vessels. Pressure values are expressed with reference to these levels. Likewise V 1 1and V 2 1are measured in the vessels. NOTEFor use of one or other of the operating procedures for determining mechanical energy per unit

48、 mass, see Clause 3. Figure 1 General schematic diagram of measuring vessels V 2 2 -BS5860:1980 BSI 12-1999 5 Other terms defining e mshall be determined by one of the operating procedures described below which are practical variations of the method. The selection of operating procedure should be ba

49、sed upon machine characteristics and the quality of measuring apparatus available. At the outlet of turbines operating under back-pressure or at pump inlets, it may be useful, depending upon the selected operating procedure, to reduce water pressure within the measuring vessel to atmospheric pressure. 3.2 “Direct” operating procedure This is characterized by the direct passage of water from the high-pressure end of the penstock to t