Re: SymHydraulics: temperature effects

As an update to this thread (from 2011), 1-D and 2-D interpolation are possible within Simscape language starting with release R2012a. An example of how to use this capability for thermal fluid systems is shown in this video:

http://www.mathworks.com/videos/modeling-an-engine-cooling-system-71894.html

This example ships with the current product, and a version of this example is available on MATLAB Central:
http://www.mathworks.com/matlabcentral/fileexchange/38339-engine-cooling-model-in-simscape

Thanks,
--Steve

"Arnaud Miege" wrote in message <ilsi1o$laf$1@ginger.mathworks.com>...
> "Guy Rouleau" <guy.rouleau.nospam@mathworks.com> wrote in message <ilr0j9$del$1@ginger.mathworks.com>...
> > Hi Sam,
> >
> > I think the best advise I can give you is to inspire your implementation from the Simscape pneumatic library, since all the source code is available. This means using the following through and across variables:
> >
> > Across variable p (pressure), in Pa
> > Through variable G (mass flow rate), in kg/s
> > Across variable T (temperature), in kelvin
> > Through variable Q (heat flow), in J/s
> >
> > Guy
>
> I concur with Guy. One thing to bear in mind is that it's not currently possible to use functions like interp1 or interp2 in the equations section of a Simscape file, so to represent the variations of fluid properties (Cp, Cv) with pressure and temperature, I would suggest you did one of two things:
> * Approximate fluid properties with a polynomial or other analytic expression, where the (constant) coefficients would be domain-wide parameters. You can then compute the relevant fluid properties in each block;
> * Set Cp, Cv, etc... as physical signal inputs to whatever block you are writing, and pressure, temperature, etc... as physical signals outputs of the blocks, and use a PS Lok-up table (1D or 2D) to represent the relationship between the fluid properties and pressure/temperature.
>
> HTH,
>
> Arnaud