1、BRITISH STANDARD 5801:200 BS 848-1:2007Industrial fans Performance testingusing standardizedairwaysICS 23.120g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3
2、g47g36g588BS EN ISOIncorporating corrigenda July 2008 cis the critical temperature of the gas. 3.11 stagnation temperature at a point Qsg absolute temperature which exists at an isentropic stagnation point for ideal gas flow without addition of energy or heat NOTE 1 The stagnation temperature is con
3、stant along an airway and, for an inlet duct, is equal to the absolute ambient temperature in the test enclosure. NOTE 2 Stagnation temperature is expressed in degrees Celsius. NOTE 3 For Mach numbers less than 0,122 obtained for standard air with duct velocities less than 40 m/s, the stagnation tem
4、perature is virtually the same as the total temperature. 3.12 fluid temperature at a point static temperature at a point Q absolute temperature registered by a thermal sensor moving at the fluid velocity BS EN ISO 5801:20084 NOTE 1 For real gas flow 2sg2pvc= where v is the fluid velocity, in metres
5、per second, at a point. NOTE 2 These temperatures are expressed in degrees Celsius. NOTE 3 In a duct, when the velocity increases, the static temperature decreases. 3.13 dry bulb temperature Td air temperature measured by a dry temperature sensor in the test enclosure, near the fan inlet or airway i
6、nlet NOTE This temperature is expressed in degrees Celsius. 3.14 wet bulb temperature Tw air temperature measured by a temperature sensor covered by a water-moistened wick and exposed to air in motion NOTE 1 When properly measured, it is a close approximation to the temperature of adiabatic saturati
7、on. NOTE 2 This temperature is expressed in degrees Celsius. 3.15 stagnation temperature at a section x Qsgxmean value, over time, of the stagnation temperature averaged over the area of the specified airway cross-section NOTE This temperature is expressed in kelvin. 3.16 static or fluid temperature
8、 at a section x Qx mean value, over time, of the static or fluid temperature averaged over the area of the specified airway cross-section NOTE This temperature is expressed in kelvin. 3.17 absolute pressure at a point absolute pressure p pressure, measured with respect to absolute zero pressure, whi
9、ch is exerted at a point at rest relative to the air around it NOTE This pressure is normally expressed in pascals. 3.18 atmospheric pressure pa absolute pressure of the free atmosphere at the mean altitude of the fan NOTE This pressure is normally expressed in pascals. BS EN 5801:200853.19 gauge pr
10、essure pe value of the pressure when the datum pressure is the atmospheric pressure at the point of measurement NOTE 1 Gauge pressure may be negative or positive pe= p paNOTE 2 This pressure is normally expressed in pascals. 3.20 absolute stagnation pressure at a point psg absolute pressure which wo
11、uld be measured at a point in a flowing gas if it were brought to rest via an isentropic process given by the following equation: 12sg112pp Ma =+ NOTE 1 Ma is the Mach number at this point (see 3.23). NOTE 2 This pressure is normally expressed in pascals. NOTE 3 For Mach numbers less than 0,122 obta
12、ined for standard air with duct velocities less than 40 m/s, the stagnation pressure is virtually the same as the total pressure. 3.21 Mach factor fMx correction factor applied to the dynamic pressure at a point, given by the expression sgMdxp pfp= NOTE The Mach factor may be calculated by: () ()( )
13、462M 223214 24 192xMa MaMaf =+ + + + 3.22 dynamic pressure at a point pd pressure calculated from the velocity and the density of the air at the point given by the following equation: 2d2vp = NOTE This pressure is normally expressed in pascals. BS EN ISO 5801:20086 3.23 Mach number at a point Ma rat
14、io of the gas velocity at a point to the velocity of sound given by the following equation: wvvMacR = where c is the velocity of sound, wcR= Rwis the gas constant of humid gas. 3.24 gauge stagnation pressure at a point pesg difference between the absolute stagnation pressure, psg, and the atmospheri
15、c pressure, pa, given by the following equation: pesg= psg paNOTE This pressure is normally expressed in pascals. 3.25 mass flow rate qm mean value, over time, of the mass of air which passes through the specified airway cross-section per unit of time NOTE 1 The mass flow will be the same at all cro
16、ss-sections within the fan airway system excepting leakage. NOTE 2 Mass flow rate is expressed in kilograms per second. 3.26 average gauge pressure at a section x mean gauge pressure at a section x pex mean value, over time, of the gauge pressure averaged over the area of the specified airway cross-
17、section NOTE This pressure is normally expressed in pascals. 3.27 average absolute pressure at a section x px mean value, over time, of the absolute pressure averaged over the area of the specified airway cross-section given by the following equation: px= pex+ paNOTE This pressure is normally expres
18、sed in pascals. BS EN 5801:200873.28 average density at a section x xfluid density calculated from the absolute pressure, px, and the static temperature, QxwxxxpR = where Rwis the gas constant of humid gas NOTE Density is expressed in kilograms per cubic metre.3.29 volume flow rate at a section x qV
19、x mass flow rate at the specified airway cross-section divided by the corresponding mean value, over time, of the average density at that section given by the following equation: mVxxqq= NOTE Volume flow rate is expressed in cubic metres per second. 3.30 average velocity at a section x vmx volume fl
20、ow rate at the specified airway cross-section divided by the cross-sectional area, Ax, given by the following equation: mVxxxqvA= NOTE 1 This is the mean value, over time, of the average component of the gas velocity normal to that section. NOTE 2 Average velocity is expressed in metres per second.
21、3.31 conventional dynamic pressure at a section x pdx dynamic pressure calculated from the average velocity and the average density at the specified airway cross-section given by the following equation: 2m2d122x mxxxqvpx A=NOTE 1 The conventional dynamic pressure will be less than the average of the
22、 dynamic pressures across the section. NOTE 2 Dynamic pressure is expressed in pascals. BS EN ISO 5801:20088 3.32 Mach number at a section x Max average gas velocity divided by the velocity of sound at the specified airway cross-section given by the following equation: mwx xxMa v R = NOTE The Mach n
23、umber is dimensionless. 3.33 average stagnation pressure at a section x psgx sum of the conventional dynamic pressure pdxcorrected by the Mach factor coefficient fMxat the section and the average absolute pressure pxgiven by the following equation: psgx= px+ pdxfMxNOTE 1 The average stagnation press
24、ure may be calculated by the equation: 12sg112xx xpp Ma =+NOTE 2 Average stagnation pressure is expressed in pascals. 3.34 gauge stagnation pressure at a section x pesgx difference between the average stagnation pressure, psgx, at a section and the atmospheric pressure, pa, given by the following eq
25、uation: pesgx= psgx paNOTE Gauge stagnation pressure is expressed in pascals. 3.35 inlet stagnation temperature Qsg1 absolute temperature in the test enclosure near the fan inlet at a section where the gas velocity is less than 25 m/s NOTE 1 In this case, it is possible to consider the stagnation te
26、mperature as equal to the ambient temperature, Qa, given by the following equation: sg1= a= Ta+ 273,15 NOTE 2 Inlet stagnation absolute temperature is expressed in kelvins. 3.36 stagnation density sg1 density calculated from the inlet stagnation pressure, psg1, and the inlet stagnation temperature,
27、Qsg1, given by the following equation: sg1sg1wsg1pR = NOTE Stagnation density is expressed in kilograms per cubic metre. BS EN 5801:200893.37 inlet stagnation volume flow rate qVsg1mass flow rate divided by the inlet stagnation density given by the formula: sg1sg1mVqq= NOTE Inlet stagnation volume f
28、low rate is expressed in cubic metres per second. 3.38 fan pressure pf difference between the stagnation pressure at the fan outlet and the stagnation pressure at the fan inlet given by the equation: pf= psg2 psg1NOTE 1 When the Mach number is less than 0,15, it is possible to use the relationship:
29、pf= ptf= pt2 pt1NOTE 2 It is possible to refer the fan pressure to the installation category A, B, C or D. NOTE 3 Fan pressure is expressed in pascals. 3.39 dynamic pressure at the fan outlet pd2 conventional dynamic pressure at the fan outlet calculated from the mass flow rate, the average gas dens
30、ity at the outlet and the fan outlet area 222d2 222122m mqvpA=NOTE Fan dynamic pressure is expressed in pascals. 3.40 fan static pressure psf conventional quantity defined as the fan pressure minus the fan dynamic pressure corrected by the Mach factor as given by the following equation: psf= psg2 pd
31、2 fM2 psg1= p2 psg1NOTE 1 It is possible to refer the fan static pressure to the installation category A, B, C or D. NOTE 2 Fan static pressure is expressed in pascals. 3.41 mean density m arithmetic mean value of inlet and outlet densities 12m2 += NOTE Mean density is expressed in kilograms per cub
32、ic metre. BS EN ISO 5801:200810 3.42 mean stagnation density msg arithmetic mean value of inlet and outlet stagnation densities given by the following equation: sg1 sg2msg2+= NOTE Mean stagnation pressure is expressed in pascals. 3.43 fan work per unit mass Wmincrease in mechanical energy per unit m
33、ass of fluid passing through the fan given by the following equation: 222121A2 A122mmmmpp vvW =+ NOTE 1 It is possible to calculate Wmas in 3.47, as follows: ummPWq= NOTE 2 The value obtained differs by only a few parts per thousand from the value given by the above expression. NOTE 3 It is possible
34、 to refer the fan work per unit mass to the installation category A, B, C or D. NOTE 4 Fan work is expressed in joules per kilogram. 3.44 fan static work per unit mass Wms increase in mechanical energy per unit mass of fluid passing through the fan minus the kinetic energy per unit mass imparted to
35、the fluid, given by the following equation: 2121sAm2mmpp vW = NOTE 1 It is possible to refer the fan static work per unit mass to the installation category A, B, C or D. NOTE 2 Fan static work is expressed in joules per kilogram. 3.45 fan pressure ratio r ratio of the average absolute stagnation pre
36、ssure at the outlet section of a fan to that at its inlet section as given by the following equation: sg2 sg1rp p= NOTE The fan pressure ratio is dimensionless. BS EN 5801:2008113.46 compressibility coefficient kp ratio of the mechanical work done by the fan on the air to the work that would be done
37、 on an incompressible fluid with the same mass flow, inlet density and pressure ratio; kpis given by the equation: ()k10p10 kloglog 1 1ZrkZr=+where sg1 rkf1mPZqp= NOTE 1 The work done is derived from the impeller power on the assumption of polytropic compression with no heat transfer through the fan
38、 casing. NOTE 2 kpand ms1/msgdiffer by less than 2 103. NOTE 3 The compressibility coefficient is dimensionless. NOTE 4 A second method of calculation is shown in 30.2.3.4.2, section b). 3.47 fan air power Pu conventional output power which is the product of the mass flow rate qmand the fan work per
39、 unit mass Wm, or the product of the inlet volume flow rate qVsg1, the compressibility coefficient kpand the fan pressure pfgiven by the following equation: usg1fpmmP qW q p k=VNOTE 1 It is possible to refer the fan air power to the installation category A, B, C or D. NOTE 2 Fan air power is express
40、ed in watts when qmis in kilograms per second and Wmis in joules per kilogram. NOTE 3 Fan air power is expressed in watts when qVsg1is in cubic metres per second and pfis in pascals. 3.48 fan static air power Pus conventional output power which is the product of the mass flow rate qmand the fan stat
41、ic work per unit mass Wms, or the product of the inlet volume flow rate qVsg1, the compressibility coefficient kpsand the fan static pressure psf; kpsis calculated using r = p2/psg1us s sg1 ps sfmmP qW q k p=VNOTE 1 It is possible to refer the fan static air power to the installation category A, B,
42、C or D. NOTE 2 The fan static air power is expressed in watts when qmis in kilograms per second and Wmsis in joules per kilogram. BS EN ISO 5801:200812 3.49 impeller power Pr mechanical power supplied to the fan impeller NOTE Impeller power is expressed in watts. 3.50 fan shaft power Pa mechanical p
43、ower supplied to the fan shaft NOTE Fan shaft power is expressed in watts. 3.51 motor output power Po shaft power output of the motor or other prime mover NOTE Motor output power is expressed in watts. 3.52 motor input power Pe electrical power supplied at the terminals of an electric motor drive NO
44、TE Motor input power is expressed in watts. 3.53 rotational speed of the impeller N number of revolutions of the fan impeller per minute 3.54 rotational frequency of the impeller n number of revolutions of the fan impeller per second 3.55 tip speed of the impeller vpperipheral speed of the impeller
45、blade tips NOTE Tip speed is expressed in metres per second. 3.56 peripheral Mach number Mau dimensionless parameter equal to the ratio of tip speed to the velocity of sound in the gas at the stagnation conditions of the fan inlet given by the following equation: uwsg1Ma u R = BS EN 5801:2008133.57
46、fan impeller efficiency hr fan air power divided by the impeller power Pras follows: urrPP = NOTE 1 It is possible to refer the fan impeller efficiency to the installation category A, B, C or D. NOTE 2 Fan impeller efficiency may be expressed as a proportion of unity or as a percentage. 3.58 fan imp
47、eller static efficiency hsr fan static power divided by the impeller power given by the equation: ussrrPP= NOTE 1 It is possible to refer the fan impeller static efficiency to the installation category A, B, C or D. NOTE 2 Fan impeller static efficiency may be expressed as a proportion of unity or a
48、s a percentage. 3.59 fan shaft efficiency ha fan air power divided by the fan shaft power given by the equation: uaaPP= NOTE 1 Fan shaft power includes bearing losses, while fan impeller power does not. NOTE 2 It is possible to refer the fan shaft efficiency to the installation category A, B, C or D
49、. NOTE 3 Fan shaft efficiency may be expressed as a proportion of unity or as a percentage. 3.60 fan motor shaft efficiency ho fan air power Pudivided by the motor output power Po asgiven by the equation: uooPP= NOTE 1 It is possible to refer the fan motor shaft efficiency to the installation category A, B, C or D. NOTE 2 Fan motor shaft efficiency may be expressed as a proportion of unity or as a percentage. BS EN ISO 5801:200814 3.61 overall efficiency he fan air
