1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58rotating anemometer performanceICS 07.060; 17.080Meteorology Wind measurements Part 1: Wind tunnel
2、test methods for BRITISH STANDARDBS ISO 17713-1:2007BS ISO 17713-1:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2007 BSI 2007ISBN 978 0 580 50835 6Amendments issued since publicationAmd. No. Date Commentscontract. Users are resp
3、onsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK implementation of ISO 17713-1:2007.The UK participation in its preparation was entrusted to Technical Committ
4、ee EH/2, Air quality.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a Reference numberISO 17713-1:2007(E)INTERNATIONAL STANDARD ISO17713-1First edition2007-05-01Meteorology
5、 Wind measurements Part 1: Wind tunnel test methods for rotating anemometer performance Mtorologie Mesurages du vent Partie 1: Mthodes dessai en soufflerie pour dterminer les caractristiques dun anmomtre tournant BS ISO 17713-1:2007ii iiiContents Foreword iv Introduction v 1 Scope 1 2 Normative refe
6、rences 1 3 Terms and definitions .1 4 Symbols and abbreviated terms 2 5 Summary of test method.3 6 Documentation.6 7 Apparatus .6 7.1 Measuring system6 7.2 Recording techniques .7 8 Test procedures.7 8.1 Starting threshold (U0) 7 8.2 Transfer function ( = a + bR + )8 8.3 Distance constant (LU) 8 8.4
7、 Off-axis response ratio (QU) Cup anemometers 9 8.5 Off-axis response ratio (QU) Vane-mounted propeller anemometers9 8.6 Off-axis response ratio (QU) Fixed-axis propeller anemometers .9 8.7 Acceptance testing10 9 Quality of the test method 10 9.1 General10 9.2 Wind tunnel 10 9.3 Repeatability.10 9.4
8、 Uncertainty .11 Annex A (normative) Wind tunnel standard test conditions 12 Annex B (informative) Examples of formats for recording run data14 Bibliography 17 BS ISO 17713-1:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodi
9、es (ISO member bodies). The work 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
10、, governmental and non-governmental, 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 IS
11、O/IEC Directives, Part 2. The main 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
12、member bodies casting a vote. 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 responsible for identifying any or all such patent rights. ISO 17713-1 was prepared by Technical Committee ISO/TC 146, Air quality
13、, Subcommittee SC 5, Meteorology. ISO 17713 consists of the following parts, under the general title Meteorology Wind measurements: Part 1: Wind tunnel test methods for rotating anemometer performance The following part is planned: Part 2: Wind tunnel test methods for wind vanes BS ISO 17713-1:2007v
14、 Introduction Cup and propeller anemometers are the most frequently used meteorological instruments for the measurement of mean wind speed in the near surface layer, that portion of the atmosphere which lies within a few tens of meters of the earths surface. Some types of cup and propeller anemomete
15、rs are available for measuring wind speeds of a few tenths of a meter per second while other types can measure wind speeds approaching 100 ms1. These general purpose anemometers are used extensively for meteorology, aviation, air pollution, wind energy and numerous other applications. This part of I
16、SO 17713 was developed in order to have a worldwide uniform set of test methods to define the characteristics of cup and propeller anemometers. This part of ISO 17713 will allow an end user to compare different manufacturers and different models of cup and propeller anemometers to determine the suit
17、ability for a particular application. BS ISO 17713-1:2007blank1Meteorology Wind measurements Part 1: Wind tunnel test methods for rotating anemometer performance 1 Scope 1.1 This part of ISO 17713 describes wind tunnel test methods for determining performance characteristics of rotating anemometers,
18、 specifically cup anemometers and propeller anemometers. 1.2 This part of ISO 17713 describes an acceptance test and unambiguous methods for measuring the starting threshold, distance constant, transfer function and off-axis response of a rotating anemometer in a wind tunnel. Note that when transfer
19、ring values determined by these methods to atmospheric flow, there is a difference between anemometer performance in the free atmosphere and in the wind tunnel. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, onl
20、y the edition cited applies. For undated references, the latest edition of the referenced document applies. ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions ISO 5725-2, Accuracy (trueness and precision) of measurement methods
21、 and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. See also References 1, 2 and 3. 3.1 distance constant LUdistance the air
22、 flows past a rotating anemometer during the time it takes the cup wheel or propeller to reach (1 1/e) or 63 % of the equilibrium speed after a step increase change in air speed 3.2 off-axis response ratio QUratio of the indicated wind speed (U) at various angles of attack () to the product of the i
23、ndicated wind speed (Ui) at zero angle of attack and the cosine of the angle of attack () and thus this ratio (QU) compares the actual off-axis response to a true cosine response BS ISO 17713-1:20072 3.3 starting threshold U0lowest wind speed at which a rotating anemometer starts and continues to tu
24、rn and produce a measurable signal when mounted in its normal operating position NOTE The normal operating position for cup anemometers is with the axis of rotation perpendicular to the direction of air flow and the normal operating position for propeller anemometers is with the axis of rotation ali
25、gned parallel with the direction of the air flow. 3.4 transfer function relationship between predicted wind tunnel air speed and the anemometer rotation rate throughout the specified working range of the anemometer: ( = a + bR + ) 4 Symbols and abbreviated terms a zero offset constant (metres per se
26、cond) b wind passage (apparent pitch) constant or calibration constant (metres per revolution) DPwind distance passage (metres) per output pulse for anemometers with pulse output signal symbol for directional degrees e base of natural logarithms L average of the distance constants (metres) at 5 ms1a
27、nd 10 ms1LUdistance constant (metres) at wind tunnel air speed U (metres per second) MRUwind speed measurement resolution, i.e. the smallest reported speed measurement increment (metres per second) for the anemometer QUoff-axis response ratio at wind tunnel air speed U (metres per second) r a shaft
28、revolution R rate of rotation (revolutions per second, rs1) t time (seconds) tf time (seconds) to reach 74 % of the anemometer equilibrium speed Uf(metres per second) ti time (seconds) to reach 30 % of the anemometer equilibrium speed Uf(metres per second) T measurement time interval (seconds) TRtim
29、e resolution of a measurement (seconds) U wind tunnel air speed (metres per second, ms1) predicted wind speed (metres per second) from the anemometer transfer function Ufanemometer indicated wind speed (metres per second) at equilibrium Uianemometer indicated wind speed (metres per second) in its no
30、rmal position in the wind tunnel BS ISO 17713-1:20073Umaxanemometer maximum specified operational speed (metres per second) Uminanemometer minimum specified operational speed (metres per second) Utinstantaneous indicated wind speed (metres per second) at time t U0 starting threshold (metres per seco
31、nd) Uindicated wind speed (metres per second) of the anemometer at off-axis angle of attack off-axis angle of attack (degrees) s stall angle for fixed-axis propeller anemometers (degrees) anemometer response time (seconds) for the equilibrium speed Uf 5 Summary of test method 5.1 This test method re
32、quires a wind tunnel described in Annex A. Additional information regarding wind tunnel testing is listed in the bibliography 7101213. 5.2 The starting threshold (U0) is determined by measuring the lowest speed at which a rotating anemometer starts and continues to turn and produce a measurable sign
33、al when mounted in its normal operating position. The anemometer axis is aligned parallel with the direction of air flow for a propeller anemometer. The anemometer axis is aligned perpendicular to the direction of air flow for a cup anemometer. 5.3 The transfer function ( = a + bR + )16is determined
34、 by measuring the rate of rotation, or output signal, of the anemometer at a number of wind speeds throughout the working range (range of intended use). In the range of wind speeds where the anemometer response is non-linear (near threshold), measurements at a minimum of five different speeds are re
35、corded. Measurements at a minimum of five additional speeds are recorded within the working range of the anemometer and wind tunnel but above the non-linear threshold region (see Figure 1). If the application working range extends into a further high speed non-linear range, then measurements at addi
36、tional speeds shall be included in that range, sufficient to enable a suitable polynomial expression to be determined. A minimum of three sets of measurements are to be taken. The values of a and b are determined by least-squares regression using the individual measurements taken at each data point.
37、 The transfer function can be approximated to a linear relationship for certain application ranges and certain anemometer designs. The function can be non-linear at low tunnel speeds (typically two to five times the U0) and again at higher speeds. is the predicted wind speed in metres per second; a
38、and b are polynomial constants. Constants beyond b would be zero for the linear relationship. For the linear case, the constant a is commonly called zero offset, in metres per second, b is a constant representing the wind passage in metres per revolution for each revolution of the particular anemome
39、ter cup wheel or propeller, and R is the rate of rotation in revolutions per second. It should be noted that zero offset is not the same parameter as the starting threshold. In some very sensitive anemometers, the constant a, zero offset, may not be significantly greater than zero. The constants a a
40、nd b shall be determined by wind tunnel measurement for each type of anemometer. In the case of anemometers that do not directly output a rate of rotation, for example, with an output directly in wind speed (ASCII, hexadecimal, etc.) or electrical units (volts, milliamperes, etc.), R and b can have
41、different units that correspond to those of the output. NOTE Although this transfer function model does not completely represent the anemometer response in the non-linear starting portion of the curve, for most applications the additional accuracy provided by more rigorous mathematics is not warrant
42、ed. These data points in the non-linear starting area can be the basis for a more advanced mathematical model of the transfer function. BS ISO 17713-1:20074 Key X wind tunnel speed, U, in metres per second Y rotation rate, R, in revolutions per second azero offset, a, in metres per second bstarting
43、threshold, U0, in metres per second Figure 1 Typical anemometer calibration curve 5.4 The distance constant (LU) shall be determined at a number of wind speeds which shall include 5 ms1and 10 ms1. It is computed from the time required for the anemometer rotor to accelerate (1 1/e) or 63 % of a step
44、increase change in rotational speed after release from a restrained, non-rotating condition 4. The final response, Uf, is the wind speed at equilibrium as indicated by the anemometer (see Figure 2). This response time () is only applicable at the particular test speed. For some applications, additio
45、nal wind speeds over the operational range can be of interest. NOTE There is a different distance constant for a decreasing step change of speed. This value will be an indicator of the amount of anemometer over speed (the anemometer reporting a wind speed value higher than the true wind speed) in gu
46、sty wind conditions. For specific anemometer applications, this distance constant for decreasing wind speed can be of interest. The determination of the distance constant for decreasing wind speeds is beyond the scope of this part of ISO 17713. The response of a rotating anemometer to a step change
47、in which the air speed increases instantaneously from U = 0 to U = Ufis 5: (/ )f(1 e )ttUU= (1) The response time is: fitt = (2) BS ISO 17713-1:20075The distance constant is: UL U= (3) Key X time, t, in seconds Y anemometer indicated wind speed, Ui, in metres per second afinal response bresponse tim
48、e, Figure 2 Typical anemometer response curve Increasing wind speed step change In order to avoid the unrealistic effects of the restrained condition, as shown in Figure 2, the time measurement should be made from 0,30 of Ufto 0,74 of Uf. This calculated response time () interval in seconds is to wi
49、thin 1 % of the theoretical (1 1/e) response of the instrument and is converted to the distance constant (LU) by multiplying by the wind tunnel air speed (U) 1. 5.5 The off-axis response ratio (QU) can be a function of speed. The off-axis response ratio shall be measured at a number of wind speeds which shall include 5 ms1and 10 ms1. 5.5.1 For cup anemometers, a measurement is made of the output signal when the anemometer is inc
