DocumentAB

�#1999 Howden Buffalo, Inc.

Appendix B

Symbols and Abbreviations

The symbols and abbreviations used in this handbook are generally theones most commonly found in the literature for the various subjects covered.Some symbols are used to represent one quantity in one chapter and a differ-ent quantity in another chapter. To avoid confusion, check the text accompa-nying each equation (or group of equations) for the definition of each symbol. The English-letter and Greek-letter symbols are listed below together withbrief descriptions and the dimensions of the quantity represented. Somesubscripted symbols are included in the lists. Additional subscripts are usedin the text as appropriate. Symbols for conversion factors are included in the above. Definitions,dimensions, and sources of numerical values are given. Finally, the abbreviations for units of measurement are listed together withtheir definitions and dimensions.

English Letter Symbols

Symbol Definition Dimensions

A area L2

A zero adjustment (see Table 1.6) ΘAR aspect ratio -

a acceleration L/T2

a surface area per unit volume L2/L3

B by-pass factor -B particle mobility T/M

b linear dimension L

C coefficient -C cost -Cb pressure conversion factor (see Table 1.5) -CF force conversion factor (see page 17-6) ML/FT2

Cg pressure conversion factor (see Table 1.5) -

© 1999 Howden Buffalo, Inc.

B-2 FAN ENGINEERING


Cm power conversion factor (see Table 2.3) -Co standard molar volume (see Table 1.10) L3/molCp pressure conversion factor (see Table 1.4) -CQ power conversion factor (see Table 2.3) -Cv velocity conversion factor (see page 2-38) FT2/MLCw power conversion factor (see Table 2.3) -CGR contaminant generation rate M/TCR curve ratio -

c linear dimension Lc velocity (sonic or other) L/Tc molal concentration mol/L3

c specific heat H/M4cp specific heat at constant pressure H/M4cv specific heat at constant volume H/M4

D diameter LD fan size LDL molecular diffusivity (liquid phase) L2/TDs specific diameter LDv molecular diffusivity (gas phase) L2/T

d prefix indicating differential -d diameter L

E effectiveness -E energy LFE Young's modulus F/L2

E electrical potential LF/TAE effects and interactions variableEv eddy diffusivity L2/TET effective temperature 4ETD equivalent temperature difference 4

e electrical charge ATe specific energy LF/Mex uncertainty in x same as xek specific kinetic energy LF/M

F weighting factor -F fraction -F force or thrust F


APPENDIX B – SYMBOLS AND ABBREVIATIONS B-3


f fraction -f coefficient of friction -f Darcy friction factor -f frequency 1/Tf� Fanning friction factor -f( ) prefix indicating function of -

G specific gravity -G shear modulus F/L2

G gas mass velocity M/TL2

Gm gas molal velocity mol/TL2

g acceleration due to gravity L/T2

gc conversion factor ML/FT

H specific humidity -H head LH height LHHV higher heating value H/M

h linear dimension Lh specific enthalpy H/Mh coefficient of heat transfer H/L2T4

I investment -I intensity (power per unit area) FL/TL2

I second moment of area L4

I electrical current AIm mass moment of inertia ML2

i interest rate 1/T

J polar moment of inertia L4

J mechanical equivalent of heat LF/H

K proportionality factor -K radius of gyration LK overall coefficient of mass transfer M/TL2'-KL loss coefficient -Kp compressibility coefficient -KR coefficient of pressure recovery -

*(The driving force A may have different dimensions depending on whether concentrationdifferences or partial pressure differences are used.)


B-4 FAN ENGINEERING


k thermal conductivity H/TL4k coefficient of mass transfer M/TL2'*

L linear dimension LL liquid mass velocity M/TL2

LM liquid molal velocity mol/TL2

LL loudness level dBLp sound pressure level dBLW sound power level dBLWs specific sound power level dBLEL lower explosive limit -LHV lower heating value H/M

1 linear dimension L

M bending moment FLM molecular weight M/molMa Mach number -MAC maximum allowable concentration -

m number -m mass Mûm mass flow rate M/T

N number -N speed of rotation 1/TNA mole flux density mol/TL2

Ns specific speed 1/T

n number -

P probability -P performance factor -P perimeter LP power LF/TPi power input to impeller LF/TPo fan output power LF/TPs shaft power or fan input power LF/TPF performance factor -

p pressure F/L2

pb barometric pressure F/L2




pD draft F/L2

pF fan pressure F/L2

pFS fan static pressure F/L2

pFT fan total pressure F/L2

pFV fan velocity pressure F/L2

pL pressure loss F/L2

pS static pressure F/L2

pSR static pressure regain F/L2

pT total pressure F/L2

pV velocity pressure F/L2

pW water pressure F/L2

pw partial pressure of water vapor F/L2

pws saturated vapor pressure F/L2

pZ elevation pressure F/L2

~Q directivity factor -Q volume L3

Q heat HûQ volume flow rate and fan flow rate L3/TûQF fan flow rate L3/TûQH total heat transfer rate H/TûQL latent heat transfer rate H/TûQS sensible heat transfer rate H/TûQS standard flow rate L3/T

q specific heat transfer H/M

R room constant L2

R ratio -R radius LR reaction force FR gas constant LF/M4R electrical resistance LF/TA2

R thermal resistance 4L2T/HR result variableRu universal gas constant FL/mol4Re Reynolds number -RR radius ratio -

r correlation coefficient -r radius L


B-6 FAN ENGINEERING


r thermal resistance 4L2T/H

S surface area L2

Sc Schmidt number -

s distance Ls stress F/L2

s specific entropy H/M4s estimated standard deviation variable

T absolute temperature 4T torque LFTL transmission loss dBTR transmissibility -

t time Tt dry-bulb temperature 4t� wet-bulb temperature 4t* temperature of adiabatic saturation 4

U internal energy LFU peripheral speed L/TU overall coefficient of heat transfer H/TL24

u specific internal energy LF/Mu velocity L/T

ùV volume L3

V volume L3

V velocity L/TV direct shear F

v specific volume L3/M

W humidity ratio -W width LW load or weight FW work LFW relative fluid velocity L/TW sound power LF/TWK2 flywheel effect FL2

w water-vapor density/dry-air density -




w mass per unit length M/Lw specific work FL/Mûw weight flow rate F/Tw specific weight F/L3

X distance or length L

x mole-fraction -x pressure-rise coefficient -x linear dimension Lx variable variable

Y distance or length L

y mole fraction -y linear dimension Ly variable variabley specific energy LF/MyF fan specific energy LF/M

Z distance or length L

z temperature-rise factor -z linear dimension L

Greek Letter Symbols


D kinetic energy factor -D sound absorption coefficient -D angle -

E momentum factor -E angle -

* tube loading M/TL

J ratio of specific heats -J angle -J shear strain L/L

' prefix indicating difference -


B-8 FAN ENGINEERING


' correction for non-standard air dB

G degree of saturation -G diameter coefficient -

� partial derivative sign -

H emissivity -H roughness LH strain L/LH error variable

] energy attenuation 1/L

K efficiency -

T angle -T time T

/ wave length L/ sound power level coefficient dB

O power coefficient -

P dynamic viscosity M/LTP true value variable

Q kinematic viscosity L2/TQ hub ratio -Q Poisson's ratio -

S 3.1415927 -

U density M/L3

Uw absolute humidity M/L3

6 prefix indicating summation -

V speed coefficient -V stress F/L2




V standard deviation variable

W throttling coefficient -W shear stress F/L2

W relaxation time TW torque LF

) flow coefficient -

I flow coefficient -I velocity of approach factor -I angle -

' relative humidity -' coefficient -

< pressure coefficient -

\ pressure coefficient -\ expansion factor

: permeance M/TF

Z angular velocity 1/T

Abbreviations for Units of Measurement

Abbreviation Definition Dimensions

A amperes AÅ angstrom units L

atm atmospheres F/L3

Btu British thermal units H

bar bars F/L2

bbl barrels L3

bu bushels L3


B-10 FAN ENGINEERING


C coulombs AT°C degrees Celsius 4cal calories Hcfm cubic feet per minute L3/Tcm centimeters LcP centipoises M/LTcps cycles per second 1/TcSt centistokes L2/T

da days TdB decibels dBdeg degrees of angle -dr drams Fdy dynes F

erg ergs LF

F farads A2T2/LF°F degrees Fahrenheit 4

fpm feet per minute L/Tfps feet per second L/Tft feet L

gf grams force Fg grams mass Mgal gallons L3

gi gills L3

gpm gallons per minute L3/Tgr grains force Fgrm grains mass M

H henrys LF/A2

Hz hertz 1/T

hp horsepower LF/Thr hours T

in. inches Lin. wg inches water gage F/L2

in. Hg inches mercury F/L2

J joules LF




K kelvins 4kcal kilocalories Hkg kilograms Mkgf kilograms force Fkg-mol kilogram moles molkip 1000 pounds FkPa kilopascal F/L2

kp kilopond Fkm kilometer LkW kilowatt LF/T

L liters L3

lb pounds force Flbm pounds mass Mlbm-mol pound moles mollyr leap year T

m meters Lmg milligrams Mmi miles Lml milliliters L3

mm millimeters Lmo months Tmol moles molmin minutes Tmph miles per hour L/T

N newtons F

oz ounces force Fozm ounces mass Moz (Vol) ounces volume L3

Pa pascal F/L2

pdl poundal FpH scale of hydrogen ion concentration -pk peck L3

ppm parts per million -psi pounds per square inch F/L2

pt pints L3

qt quarts L3


B-12 FAN ENGINEERING


°R degrees Rankine 4rad radians -rev revolutions -rpm revolutions per minute 1/Trps revolutions per second 1/T

S seimens AFT/L

sc scruples Fs seconds Tslug slugs M

V volts LF/TA

W watts LF/T

wk weeks T

yd yards Lyr years T

: ohms LF/TA2

$ dollars -

% percent -st� seconds of angle -s� minutes of angle -° degrees of angle -

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