Contents of the README.1ST file
Interactive Fortran Programs for Micro Computers to Calculate
Thermophysical Properties of Twelve Fluids
Robert D. McCarty
Thermophysical Properties Division
National Engineering Laboratory
Boulder, Colorado 80303
These programs were prepared by the National Bureau of Standards.
The source code is in FORTRAN 77 and is compatable with Microsoft
FORTRAN. The code provided in this archive was compliled on an
IBM AT without the coprocessor option. If you own a FORTRAN 77
compiler, then I suggest that you recompile the source code. In
this way you can insure compatiblility and take full advantage of
your particular hardware arrangement.
The program source code and documentation is available from the
NBS. If you wish to have a copy write the Office of Standard
Reference Data, Room A320, Physics Building, National Bureau of
Standards, Gaithersburg, MD 20899.
The program is fairly self explanatory, allowing you to get
started with out the full documentation. So that you may better
understand how the program functions, I have paraphrased some of
To run the compiled version of MIPROPS, just type miprops at the
prompt. To run the helium routine type helium. When you enter
the program, instructions will be provided.
The programs allow the user to input pressure, phase, and tem-
perature in the single phase regions and either pressure or tem-
perature in the saturated liquid or vapor states. The program
output is pressure, density, temperature, internal energy, en-
thalpy, entropy, specific heat capacities, speed of sound, and in
most cases, viscosity, thermal conductivity and dielectric con-
The fluids insulated are: helium, hydrogen, nitrogen, oxygen, ar-
gon, nitrogen trifluoride, methane, ethylene, ethane, propane,
iso- and normal butane.
All of the fluids use the same mathematical model except for
helium. The model for the helium dynamic surface is of a dif-
ferent form, and a separate program is required for that fluid.
The programs present the transport properties for all of the
fluids except hydrogen, nitrogen trifluoride, ethylene, ethane,
and propane. Dielectric constant is provided for all fluids with
the exception of argon, ethylene, and nitrogen trifluoride.
Uncertainties of the Calculated Properties
When calculating the thermophysical properties from an emperical
equation of state, one should be aware of certain problem areas
of the thermodynamic surface. In the critical region (critical
pressure plus or minus 0.2 of critical pressure and critical tem-
perature plus or minus 0.05 of critical temperature), the calcu-
lated density may be in error by several percent, while pressure
and temperature will not be as inaccurate. Values of specific
heat capacity and thermal conductivity in the critical region be-
come very large and no realistic estimate of uncertainty can be
made. Saturation boundaries, gas-liquid, and liquid-solid are
potential areas for large uncertainties for derived thermodynamic
properties, especially heat capacities. In the compressed liquid
region, calculated pressures will have an uncertainty of several
percent. This is a consequence of the nature of the surface and
is in know way the fault of the equation of state.
I am an engineer working for a space agency contractor. This
program has been a tremendously valuable tool in our calculations
for fluid handling and storage systems, relief valve sizings,
safety problems, insulation efficiency calculations, and much
more. If you work in a similar business or research I am sure
you also will derive much benefit. I do however recommend that
you request a copy of the program and documentation from the NBS.
In this way you will have a more complete program reference and
may learn of impending updates to the program. I have heard
through contacts at the NBS that a revision may be coming, when I
do not know. It should have a more comfortable user interface
and possibly some improved algorithms. ENJOY!