Data Useful in Heat and Mass Transfer


Whenever assigning property data in a heat transfer problem, bear in mind that many properties (especially liquid viscosity) are very sensitive to temperature changes. Pressure variations often have less impact on transport properties, although they can significantly alter thermodynamic properties such as the density of gases and liquid boiling points. Pressure is often important in phase change processes.

The thermal conductivity of solids can vary significantly with: alloying processing, density or compaction, and water content. For example, the conductivity of pure iron is 80W/m-K, of 1.0% carbon steel is 43 W/m-K, and of 304 stainless steel is 14 W/m-K, each at 293 K.

This page is divided into a few sections:


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Some sources for physical properties of matter


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Some physical constants


2002 CODATA with (1 sigma) uncertainty
Avogadro's number 6.0221415(10) x 1026 molecules/kmol
Boltzmann's constant 1.3806505(24) x 10-23 J/K
Ideal gas constant 8314.472(15) J/kmol-K
Speed of light 2.99792458(0) x 108 m/s
Gravitational acceleration 9.80665(0) m/s2
Stefan-Boltzmann constant 5.670400(40) x 10-8 W/m2-K4

NIST physical constants web site
 

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Some conversion factors


Quantity S.I. Units = Multiplier x Other Units
density kg/m3 = 16.018 x lbm/ft3
kg/m3 = 103 x g/cm3
diffusivity m2/s = 0.092903 x ft2/s
m2/s = 10-6 x centistokes
energy J = 1055.04 x Btu
J = 4.1868 x calorie
flow rate m3/s = 6.3090 x 10-5 x gal/min (gpm)
m3/s = 4.7195 x 10-4 x ft3/min (cfm)
heat flux W/m2 = 3.154 x Btu/hr-ft2
heat transfer coefficient W/m2-K = 5.67826 x Btu/hr-ft2-F
length m = 0.0254 x inches
m = 0.3048 x feet
power W = 0.022597 x ft-lb/min
W = 0.29307 x Btu/hr
W = 745.700 x horsepower
pressure Pa = 248.8 x in. H2O
Pa = 6894.8 x psi
Pa = 101325. x atm
specific heat J/kg-K = 4186.9 x Btu/lbm-F
J/kg-K = 4186.8 x cal/g-C
thermal conductivity W/m-K = 1.7307 x Btu/hr-ft-F
W/m-K = 418.68 x cal/s-cm-C
dynamic viscosity Pa-s = 10-3 x centipoise
Pa-s = 1.4881 x lbm/ft-s
Pa-s = 47.8803 x lbf-s/ft2
temperature K = 5/9 x R
K = 273.15 + C
K = (459.67 + F)/1.8
Quantity S.I. Unit = Multiplier x Other Unit

NIST booklet on SI units and conversion factors (pdf version of publication SP811)
 

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