'PTC Mathcad Prime 3.0 does not support the use of an Excel component to define functions. Since I didn't have any 15.0 worksheets to convert I didn't read through the conversion guide, but later I found this note: At first it seemed to work, but later I noticed that, most of the time it didn't (the function call returned a #VALUE error message indicating Excel couldn't find it). With the NIST-supplied REFPROP add-in loaded into my copy of Excel, I opened a Prime 3.0 worksheet, added an Excel component, and entered a REFPROP function call. I looked at Prime 2.0 last year, but based on how 'crippled' it seemed to be relative to 15.0 I held off until Prime 3.0 came out. I'm a long-time user of the Excel Add-in (and creating a DLL is beyong my programming level), but, given how units-intensive most of my calcs are, I was interested in seeing if Mathcad might be a viable alternative. The underlying code base in written in Fortran, but NIST provides several different methods for accessing the property data including:ģ) instructions for adding wrapper code to create C-code compatible DLL's We use a NIST Standard Reference Database ( ) called REFPROP to get the thermodynamic and transport properties needed to support our fluid calcs. COMSOL will interpolate between your data points.I'm an engineer at NASA. Create a matrix of x number of values within the limits you expect to see in your simulation and import that as a definition for your properties. Alter the NIST FORTRAN code to accept an arbitrary sized matrix for input instead of a single valueģ. Create another function that calls your NIST to Matlab function and runs the matrix through a series of for loops.Ģ. The NIST code is written for a single input and thus you will get errors. The issue now becomes the fact that if you try to obtain properties from NIST using a general variable in COMSOL like function(T,p), COMSOL sends these variables as matrices. Next you use this newly created Matlab function in COMSOL. This process is demonstrated in the examples of Matlab. In order for this to work, one must slightly modify the FORTRAN code in order to create a Matlab function that calls the code. For a point of reference, I am using the FORTRAN version of REFPROP. I have been able to successfully link NIST REFPROP to Matlab and in turn use it in COMSOL.

Nist refprop program