The default units for the thermophysical properties listed in Table 1 can be altered by using the base units listed in Table 2 using the SetUnits method. In addition to the default (FluidProp) unit set, two different unit sets can be specified: the SI and the Anglo-Saxon unit set. Units are per mass by default (cF. Table 1) but can be specified per mole as well. Non-dimensional properties can be obtained by defining a reference state by using the SetRefState method.
Table 1
Property name |
Symbol |
Default
|
SI |
Anglo-Saxon
|
Pressure |
P |
bar |
Pa |
psia |
Temperature |
T |
°C |
K |
°F |
Specific volume |
v |
m^3/kg |
m^3/kg |
ft^3/lb |
Density |
d |
kg/m^3 |
kg/m^3 |
lb/ft^3 |
Enthalpy |
h |
kJ/kg |
J/kg |
Btu/lb |
Entropy |
s |
kJ/kg/K |
J/kg/K |
Btu/lb/°R |
Internal energy |
u |
kJ/kg |
J/kg |
Btu/lb |
Isobaric heat capacity |
cp |
kJ/kg/K |
J/kg/K |
Btu/lb/°R |
Isochoric heat capacity |
cv |
kJ/kg/K |
J/kg/K |
Btu/lb/°R |
Speed of sound |
c |
m/s |
m/s |
ft/s |
( |
alpha |
m^2/s^2 |
m^2/s^2 |
ft^2/s^2 |
( |
beta |
kg/m^3 |
kg/m^3 |
lb/ft^3 |
( |
chi |
N.m^4/kg^2/K |
N.m^4/kg^2/K |
lbf.ft^4/lb^2/°R |
( |
fi |
K^-1 |
K^-1 |
°R^-1 |
( |
ksi |
kg^2/N/m^4 |
kg^2/N/m^4 |
lb^2/lbf/ft^4 |
( |
psi |
s^2/m^2 |
s^2/m^2 |
s^2/ft^2 |
( |
zeta |
kg.K/m^3 |
kg.K/m^3 |
lb.°R/ft^3 |
Volumetric thermal expansion coefficient |
theta |
K^-1 |
K^-1 |
°R^-1 |
Isothermal compressibility |
kappa |
bar^-1 |
Pa^-1 |
psia^-1 |
Dynamic viscosity |
eta |
Pa.s |
Pa.s |
lb/ft/s |
Thermal conductivity |
lambda |
W/m/K |
W/m/K |
Btu/h/ft/°F |
Table 2
Property name |
Base units |
|||||
Length |
m |
in |
ft |
yd |
mi |
|
Mass |
g |
lb |
oz |
|
|
|
Time |
s |
min |
h |
d |
y |
|
Temperature |
K |
°C |
°F |
°R |
|
|
Temperature difference |
K |
°C |
°F |
°R |
|
|
Area |
m2 |
a |
sq in |
sq ft |
sq yd |
acre |
Volume |
m3 |
L |
cu in |
cu ft |
cu yd |
cc |
Speed |
m/s |
mph |
kn |
|
|
|
Force |
N |
gf |
lbf |
|
|
|
Pressure, stress |
Pa |
bar |
atm |
mHg |
psia |
|
Energy, work, heat |
J |
Wh |
cal |
Btu |
|
|
Power |
W |
hp |
|
|
|
|
Base units can be preceded (if applicable) by the prefixes listed in Table 3.
Table 3
Prefix |
Name |
Factor |
Prefix |
Name |
Factor |
y |
yocto |
10^-24 |
da |
deca |
10^+1 |
z |
zepto |
10^-21 |
h |
hecto |
10^+2 |
a |
atto |
10^-18 |
k |
kilo |
10^+3 |
f |
femto |
10^-15 |
M |
mega |
10^+6 |
p |
pico |
10^-12 |
G |
giga |
10^+9 |
n |
nano |
10^-9 |
T |
tera |
10^+12 |
mu |
micro |
10^-6 |
P |
peta |
10^+15 |
m |
milli |
10^-3 |
E |
exa |
10^+18 |
c |
centi |
10^-2 |
Z |
zeta |
10^+21 |
d |
deci |
10^-1 |
Y |
yotta |
10^+24 |
Base units, possibly preceded by a prefix, can be used together in arbitrary combinations. For instance the unit of the specific heat capacity (J/kgK) can be formed by combining the units of energy, mass and temperature difference dT by means of the operators listed in Table 4.
Table 4
Operator
|
Name |
Meaning |
. |
period |
multiply |
/ |
slash |
divide |
^ |
circumflex |
power |
A compound unit consists of a row of base units, possibly raised to a certain power, separated by a period or a slash. A base unit raised to a power consists of base unit followed by circumflex and after that a positive or negative number. If no power is specified, the power defaults to 1. For example if a pressure is to be specified as Newton per square meter then it can be written as N/m^2 (or N.m^-2). The number of base units in a compound unit is unlimited. Each base unit and its power form a unit itself. This means that a period or slash in front of the preceding unit does not affect the unit thereafter. Therefore the unit of the specific heat capacity must be written as J/kg/K, or J.kg^-1.K^-1, or J/kg.K^-1, or J.kg^-1/K and certainly not as J/kg.K.
For more examples, see SetUnits.