1、DEUTSCHE NORM Auaust 1996 - DIN EN IS0 9288 Th ermal i nsu I at ion Heat transfer by radiation: Physical quantities and definitions (IS0 9288:1989) Enalish version of DIN EN IS0 9288 This standard incorporates the English version of Is0 9288. ICs 01.040.91; 01.060.20; 91.120.10 Descriptors: Thermal
2、insulation, physical quantities, vocabulary, symbols, building and civil engineering. Wrmeschutz; Wrmebertragung durch Strahlung; physikalische Gren und Definitionen (IS0 9288: 1989) European Standard EN IS0 9288: 1996 has the status of a DIN Standard. A comma is used as the decimal marker. National
3、 foreword This standard has been published in accordance with a decision taken by CENTC 89 to adopt, without alteration, International Standard IS0 9288 as a European Standard. The responsible German body involved in its preparation was the Normenausschu Bauwesen (Building and Civil Engi- neering St
4、andards Committee). The DIN Standards corresponding to the International Standards referred to in the Introduction and clause 2 of the EN are as follows: IS0 Standard DIN Standard IS0 7345 DIN 4108-1 and DIN EN IS0 7345 IS0 9251 DIN EN IS0 9251 IS0 9346 DIN EN IS0 9346 Standards referred to (and not
5、 included in Normative reference) DIN 4108-1 Thermal insulation of buildings; physical quantities and units DIN EN IS0 7345 Thermal insulation; physical quantities and definitions (IS0 7345: 1995) DIN EN IS0 9251 Thermal insulation; heat transfer conditions and properties of materials; vocabulary (I
6、S0 9251 :1987) DIN EN IS0 9346 Thermal insulation; mass transfer; physical quantities and definitions (IS0 9346: 1987) EN comprises 20 pages. Eeuth Verlag GmbH, Berlin, has the exclusive right of sale for German Standards (DIN-Normen). 03.97 DIN EN IS0 9288 Eng/. Price group 11 Sales No. 1 11 1 EURO
7、PEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 9288 May 1996 ICs 01.040.91; 01.060.20; 91.120.10 Descriptors: Thermal insulation, physical quantities, vocabulary, symbols, building and civil engineering. English version Thermal insulation Heat transfer by radiation Physical quantities and defi
8、nitions (IS0 9288: 1989) Isolation thermique; transfert de chaleur par rayonnement; grandeurs physiques et dfinitions (IS0 9288:1989) Wrmeschutz; Wrmebertragung durch Strahlung; physikalische Gren und Definitionen (IS0 9288: 1989) This European Standard was approved by CEN on 1995-01-05 and is ident
9、ical to the IS0 Standard as referrend to. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibiiographical references concerning suc
10、h 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, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language
11、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, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and Unite
12、d Kingdom. (EN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, 6-1 050 Brussels O 1996. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN
13、 IS0 9288: 1996 E Page 2 EN IS0 9288 : 1996 Foreword International Standard IS0 9288:1989 Thermal insulation; Heat transfer by radiation; physical quantities and definitions, which was prepared by ISO/TC 163 Thermal insulation of the International Organization for Standardization, has been adopted b
14、y Technical Committee CEN/TC 89 Thermal performance of buildings components as a European Standard. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national standards withdrawn, by November 1996 at
15、 the latest. In accordance with the CENKENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and
16、 United Kingdom. Endorsement notice The text of the International Standard IS0 9288:1989 was approved by CEN as a European Standard without any modification. Page 3 EN ISO9288:1996 Paae Contents Introduction 3 1 Scope . 3 2 Normative reference 4 3 General terms . 4 4 Terms related to surfaces either
17、 receiving, transferring or emitting a thermal radiation 5 . 5 Terms related to surfaces emitting a thermal radiation. . 6 Terms related to opaque or semi-transparent surfaces receiving a thermal radiation . 9 7 7 Terms related to a semi-transparent medium receiving a thermal radiation - Combined co
18、nduction and radiation heat transfer . 12 Annex A Bibliography 19 Alphabeticalindex . 20 Introduction This International Standard forms part of a series of vocabularies related to thermal insulation. The series will include IS0 7345 : 1987, Thermal insulation - Physical quantities and definitions. I
19、S0 9229 : -I, Thermal insulation - Thermal insulating materials and products - Vocabulary. IS0 9251 : 1987. Thermal insulation - Heat transfer conditions and properties of materials - Vocabulary. IS0 9346 : 1987, Thermalinsulation - Mass transfer - PhysIcalquanttes and defini- tions. 1) To be publis
20、hed. Page 4 EN IS0 9288 : 1996 I 1 Scope This international Standard defines physical quantities and other terms in the field of thermal insulation relating to heat transfer by radiation. Solar radiation -0,lp-n - 3 pm 3 General terms 2 Normative reference The following standard contains provisions
21、which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encour- aged to investigate the possibit
22、ity of applying the most recent edition of the standard indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 7345 : 1987, Thermal insulation - Physical quantities and definitions. 3.1 thermal radiation : Electromagnetic radiation emitted at the s
23、urface of an opaque body or inside an element of a semi- transparent volume. The thermal radiation is governed by the temperature of the emitting body and its radiative characteristics. It is interesting from a thermal viewpoint when the wavelength range falls be- tween 0.1 pm and 100 vrn (see figur
24、e l). 3.2 heat transfer by radiation: Energy exchanges between bodies (apart from one another) by means of electromagnetic waves, These exchanges can occur when the bodies are separated from one another by vacuum or by a transparent or a semi- transparent medium. To evaluate these radiation heat ex-
25、 changes it is necessary to know how opaque and semi- transparent bodies emit, absorb and transmit radiation as a function of their nature, relative position and temperature. Figure 1 - Electromagnetic wave spectrum Page 5 EN IS0 9288 : 1996 3.3 thermal radiation Physical terms associated with therm
26、al radiation are classified according to two criteria : Classification of the physical terms associated with - spectral distribution - spatial distribution (directional) of the radiation. These physical terms are : total, if they are related to the entire spectrum of thermal radiation (this designat
27、ion can be considered as implicit); spectral or monochromatic, if they are related to a spec- tral interval centred on the wavelength A: hemispherical, if they are related to all directions along which a surface element can emit or receive radiation; directional, if they are related to the direction
28、s of propaga- tion defined by a solid angle around the defined direction. 3.4 Classification of materials in relation with radiative transfer opaque medium : Medium which does not transmit any frac- tion of the incident radiation. The absorption, emission, reflection of radiation can be han- dled as
29、 surface phenomena, semi-transparent medium: Medium in which the incident radiation is progressively attenuated inside the material by ab- sorption or scattering, or both. The absorption, scattering and emission of radiation are bulk (volume) phenomena. The radiative properties of an opaque or semi-
30、transparent medium are generally a function of the spectral and directional distribution of incident radiation and of the temperature of the medium. NOTE - Themial insulating materials are generally semi-transparent media. 4 Terms related to surfaces either receiving, transferring or emitting a ther
31、mal radiation 4.1 system in form of electromagnetic waves. radiant heat flow rate; radiant flux: Heat flow rate emitted, transferred or received by a NOTE - This is a total hemispherical quantity 4.2 total intensity: Radiant heat flow rate divided by the solid angle around the direction d : - 4.3 an
32、d the projected area normal to this direction : total radiance: Radiant heat flow rate divided by the solid angle around the direction A 4.4 centred on the wavelength A : spectral radiant heat flow rate: Radiant heat flow rate divided by the spectral interval ao o, = - a, 4.5 spectral intensity: Tot
33、al intensity divided by the spectral interval centred on the wavelength 1 : Symbol for quantity Symbol for SI unit (including multiple or sub-multiple i W W/sr W/rn2.si W/m W/vm Page 6 EN IS0 9288 : 1996 4.6 spectral radiance: Total radiance divided by the spectral interval centred on the wavelength
34、 A : NOTES 1 Each spectral term AA is related to the corresponding total term A by a relation of the type a aA al A, = -orA =IAhdA O Each directional term A, is related to the corresponding hemispherical term A by a relation of the type an an AO = -orA = i AndQ R-4n and f1=4x o 2 Total radiance and
35、spectral radiance are oriented quantities (vectors) defined in each point of space where radiation exists (see figure 3), moreover their values are independent of the particular surface used to define them. Sources which radiate with constant LQ (see 4.3) are called isotropic or diffuse. Intensities
36、 are again oriented quantities but belong to a surface see figure 2). Radiant flows (total or spectral) are not oriented quantities and belong to a surface. 4.7 spectral radiant density of heat flow rate vector: R=4n 4.8 total radiant density of heat flow rate vector: O R=4n + 4.9 spectral radiant d
37、ensity of heat flow rate (in the direction n ) : Symbol for quantity Symbol for Si unit (including multiple or su b-multiple) W/m3 W/m2 Page 7 EN IS0 9288 : 1996 4.10 forward component of the spectral radiant density of heat flow rate: 4.11 backward component of the spectral radiant density of heat
38、flow rate: NOTES 1 We can express qr,ln by !he following expression: 9r.ln = q,+An - qryAn In combined unidirectional conduction and radiation heat transfer along a direction n , we have qn 4cd.n qr.n 4 2 -+ 2 where 9, is the density of heat flow rate as defined in IS0 7345 : 1987, 2.3; 9cd,n is the
39、 density of heet flow rate by conduction; qr,n is the total radiant density of heat flow rate vector; qn - -I + - can be determined experimentally with the guarded hot plate or heat flow meter method. 5 Terms related to surfaces emitting a thermal radiation 5.1 solids, etc.) is transformed into elec
40、tromagnetic waves. emission: Process in which heat (from molecular agitation in gases or atomic agitation in 5.2 emitting surface: total excitance: Radiant heat flow rate emitted by a surface divided by the area of the NOTE - M is the areal density of the heat flow rate in each point of an emitting
41、surface. It is a total hemispherical quantity. 5.3 wavelength 1 : spectral excitance: Total excitance divided by the spectral interval, centred on the Symbol for quantity Symbol for SI unit (including multiple or sub-multiple I W/m2 Page 8 EN IS0 9288 : 1996 5.4 black body, (full radiator or Planck
42、radiator): The black body is one that absorbs all the incident radiation for all wavelengths, directions and polarizations. At a given temperature, for each wavelength it emits the maximum thermal energy (maximum spectral excitance). For this reason and because rigorous laws define its emission, the
43、 emission of real bodies is compared with that of the black body. NOTE - Terms related to black body bear a superscript notation Io). 5.5 black body total excitance: It is expressed by the Stefan-Boltzmann law: Mo = uT4 where u is equal to 5,67 x lo-* W/m2.K4); T is the absolute temperature of the b
44、lack body. 5.6 wavelength A and to the absolute temperature of the black body: black body spectral excitance: It is expressed by Plancks law which relates M4 to the C,-5 “(1“ = expC2/A.Ti - 1 where Cl = 2nhc: = 3.741 x 1016 W/m2; Cz = hq/k = 0,014 388 m.K. h and k are, respectively, the Planck const
45、ant and the Boltzmann constant, c, is the speed of electromagnetic waves in vacuum. A curve My = fil) with a maximum at I, can be drawn far each temperature. A, is a function of temperature, but the product A,.T is constant (Wiens “displacement law“) : i;T = 2,898 x m.K Mo and Mi are hemispherical t
46、erms. The emission of a black body is isotropic or diffuse, .e. Lo and Li are independent of the direc- tion (Lamberts law). The total and the spectral radiance of the black body are expressed by MO LO = - n M; L; = - x 5.7 emission of real bodies: The evaluation of the emission properties of real m
47、aterials is made relative to the black body placed in the same conditions of temperature. In general, these properties depend on the nature and surface aspect of the body and vary with wavelength, direc- tion of emission and surface temperature. Symbol for quantity MO Symbol for SI unit (including m
48、ultiple or sub-multiple) W/m2 Page 9 EN IS0 9288 : 1996 5.8 total directional emissivity: Total radiance, L, emitted by the considered surface, divided by total radiance emitted by the black body, Lg, at the same temperature: Lf2 E* = - LR 5.9 ded by the spectral radiance emitted by the black body,
49、i.;, at the same temperature: spectral directional emissivity: Spectral radiance, Lnr, of the considered surface divi- 5.10 total hemispherlcel emissivity: Total hemispherical excitance, M. of the considered surface divided by the total hemispherical excitance of the black body, Mo, at the same temperature : 5.1 1 divided by the spectral excitance of the black body, M!, at the same temperature: spectral hemispherical emissivity: Spectral excitance, MA, of the considered surface MA MY El = - 5.12 grey body: Thermal radiator whose hemispherical or direct
