DIN ISO 17713-1-2007 Meteorology - Wind measurements - Part 1 Wind tunnel test methods for rotating anemometer performance (ISO 17713-1 2007) English version of DIN ISO 17713-1 200.pdf

1、October 2007DEUTSCHE NORM English price group 12No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).!$IG“1383688www.din.deDDIN

2、 ISO 17713-1Meteorology Wind measurements Part 1: Wind tunnel test methods for rotating anemometer performance(ISO 17713-1:2007)English version of DIN ISO 17713-1:2007-10Meteorologie Windmessungen Teil 1: Prfverfahren in Windkanlen zur Ermittlung der Leistung vonRotationsanemometern (ISO 17713-1:200

3、7)Englische Fassung DIN ISO 17713-1:2007-10www.beuth.deDocument comprises 21 pages ICS 07.060This standard has been included in the VDI/DIN Handbook on air quality, Volume 1 B. DIN ISO 17713-1:2007-10 2 Contents Page National Foreword .2 National Annex NA (informative) Bibliography .3 Introduction 4

4、 1 Scope .5 2 Normative references .5 3 Terms and definitions 5 4 Symbols and abbreviated terms .6 5 Summary of test method 7 6 Documentation 10 7 Apparatus 10 7.1 Measuring system10 7.2 Recording techniques 11 8 Test procedures 11 8.1 Starting threshold (U0) 11 8.2 Transfer function ( = a + bR +) .

5、12 8.3 Distance constant (LU) 12 8.4 Off-axis response ratio (QU) Cup anemometers 13 8.5 Off-axis response ratio (QU) Vane-mounted propeller anemometer 13 8.6 Off-axis response ratio (QU) Fixed-axis propeller anemometers 14 8.7 Acceptance testing 14 9 Quality of the test method 14 9.1 General 14 9.2

6、 Wind tunnel 14 9.3 Repeatability 14 9.4 Uncertainty 15 Annex A (normative) Wind tunnel standard test conditions .16 Annex B (informative) Examples of formats for recording run data .18 Bibliography .21 National foreword This standard has been prepared by Technical Committee ISO/TC 146 “Air quality”

7、, Subcommittee SC 5 “Meteorology”. The responsible German body involved in its preparation was the Kommission Reinhaltung der Luft (KRdL) im VDI und DIN (VDI/DIN Air Quality Commission), Section II Umweltmeteorologie. The DIN Standards corresponding to the International Standards referred to in this

8、 document are as follows: ISO 5725-1 DIN ISO 5725-1 ISO 5725-2 DIN ISO 5725-2 DIN ISO 17713-1:2007-10 3 National Annex NA (informative) Bibliography DIN ISO 5725-1, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions DIN ISO 5725-2, Accurac

9、y (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method Introduction Cup and propeller anemometers are the most frequently used meteorological instruments for the measurement of mea

10、n 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 anemometers are available for measuring wind speeds of a few tenths of a meter per second while other types can measure wind speeds app

11、roaching 100 ms1. These general purpose anemometers are used extensively for meteorology, aviation, air pollution, wind energy and numerous other applications. This part of ISO 17713 was developed in order to have a worldwide uniform set of test methods to define the characteristics of cup and prope

12、ller 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 suitability for a particular application. 4 DIN ISO 17713-1:2007-10Meteorology Wind measurements Part 1: Wind tunnel test methods

13、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, specifically cup anemometers and propeller anemometers. 1.2 This part of ISO 17713 describes an acceptance test and unambiguo

14、us 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 transferring values determined by these methods to atmospheric flow, there is a difference between anemometer performance in the free

15、atmosphere and in the wind tunnel. 2 Normative references The following referenced documents 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 applies. ISO 5725-1, Accura

16、cy (trueness and precision) of measurement methods and results Part 1: General principles and definitions ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method

17、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 flows past a rotating anemometer during the time it takes the cup wheel or propeller to reach (1 1/e) or 63 % of the equilibr

18、ium 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 indicated wind speed (Ui) at zero angle of attack and the cosine of the angle of attack () and thus this ratio (QU) compares th

19、e actual off-axis response to a true cosine response 5 DIN ISO 17713-1:2007-103.3 starting threshold U0lowest wind speed at which a rotating anemometer starts and continues to turn and produce a measurable signal when mounted in its normal operating position NOTE The normal operating position for cu

20、p 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 aligned parallel with the direction of the air flow. 3.4 transfer function relationship between predicted wind tunnel air spe

21、ed 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 second) b wind passage (apparent pitch) constant or calibration constant (metres per revolution) DPwind distance passage (me

22、tres) 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 ms1and 10 ms1LUdistance constant (metres) at wind tunnel air speed U (metres per second) MRUwind speed measurement resolution,

23、 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 revolution R rate of rotation (revolutions per second, rs1) t time (seconds) tf time (seconds) to reach 74 % of the anemom

24、eter 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) TRtime resolution of a measurement (seconds) U wind tunnel air speed (metres per second, ms1) predicted wind speed (metres per

25、second) from the anemometer transfer function Ufanemometer indicated wind speed (metres per second) at equilibrium Uianemometer indicated wind speed (metres per second) in its normal position in the wind tunnel 6 DIN ISO 17713-1:2007-10Umaxanemometer maximum specified operational speed (metres per s

26、econd) Uminanemometer minimum specified operational speed (metres per second) Utinstantaneous indicated wind speed (metres per second) at time t U0 starting threshold (metres per second) Uindicated wind speed (metres per second) of the anemometer at off-axis angle of attack off-axis angle of attack

27、(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 requires a wind tunnel described in Annex A. Additional information regarding wind tunnel testing is listed in the bibl

28、iography 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 signal when mounted in its normal operating position. The anemometer axis is aligned parallel with the direction of air f

29、low 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 by measuring the rate of rotation, or output signal, of the anemometer at a number of wind speeds throughout the wor

30、king 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 recorded. Measurements at a minimum of five additional speeds are recorded within the working range of the anemometer a

31、nd 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 additional speeds shall be included in that range, sufficient to enable a suitable polynomial expression to be determined

32、. 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. The transfer function can be approximated to a linear relationship for certain application ranges and certain anemom

33、eter 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 and b are polynomial constants. Constants beyond b would be zero for the linear relationship. For the linear case, th

34、e 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 anemometer cup wheel or propeller, and R is the rate of rotation in revolutions per second. It should be noted that zero off

35、set 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 and b shall be determined by wind tunnel measurement for each type of anemometer. In the case of anemometers that do n

36、ot 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 different units that correspond to those of the output. NOTE Although this transfer function model does not completel

37、y 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 warranted. These data points in the non-linear starting area can be the basis for a more advanced mathematical model of the

38、transfer function. 7 DIN ISO 17713-1:2007-10Key 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 threshold, U0, in metres per second Figure 1 Typical anemometer calibration curve 5.4 The distance constant (LU)

39、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 increase change in rotational speed after release from a restrained, non-rotating condition 4. The final response

40、, 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, additional wind speeds over the operational range can be of interest. NOTE There is a different distance constant for a

41、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 gusty wind conditions. For specific anemometer applications, this distance constant for decreasing wind speed can b

42、e 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 in which the air speed increases instantaneously from U = 0 to U = Ufis 5: (/ )f(1 e )ttUU= (1) The response time

43、 is: fitt = (2) 8 DIN ISO 17713-1:2007-10The 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 time, Figure 2 Typical anemometer response curve Increasing wind speed step change In order to avoid the unreal

44、istic 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 within 1 % of the theoretical (1 1/e) response of the instrument and is converted to the distance constant (LU

45、) 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 wh

46、en the anemometer is inclined into the wind (representing a down-draft) and away from the wind (representing an updraft), while the wind tunnel is running at a steady speed. The output signal is measured with the anemometer axis at 5 intervals from vertical to 30 from vertical. The measured signal i

47、s then converted to a ratio for each interval by dividing by the product of cosine of the angle and the signal measured with the anemometer axis in the normal (vertical) position. 5.5.2 For vane-mounted propeller anemometers, a measurement is made of the output signal when the anemometers axis of ro

48、tation is inclined downward into the wind (representing a down-draft) and inclined upward into the wind (representing an updraft), while the wind tunnel is running at a steady speed. The output signal is measured as 5 intervals from a horizontal axis of rotation to 30 from the horizontal. The measur

49、ed signal is then converted to a ratio for each interval by dividing by the product of the cosine of the angle and the signal measured with the anemometer axis in the normal (horizontal) position. This test may be conducted either with the vane in place or with the vane removed. In either case, the axis of rotation shall be fixed in the down-tunnel direction. 9 DIN ISO 17713-1:2007-105.5.3 For fixed-axis propeller anemometers, a measurement is made of the output signal w