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Phase change with steam

Question asked by Andrew Ross on Jul 24, 2017
Latest reply on Jul 25, 2017 by Andrew Ross

I am attempting to run a heat exchanger with steam through a helical coil. The steam starts as unsaturated with a quality of zero and I would like to know how much latent heat is absorbed. The heat is being gained from combustion and so I have the inputs to the coil to conduct from a hot environment of 600K and have the flame surface as a radiative surface of 180,000 W. I realize that combustion is a whole other story but I am happy with the boundary conditions of the heat source for now. It looks like this with the red transparent body approximating the flame volume:

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I understand that SW Flow does not natively handle phase change but nonetheless I am following the instructions from S-019412 to define the steam. I have set up steam as an ideal gas material with a specific heat profile to account for the latent energy absorbed during phase change:

 

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I am only interested in the phase change region which is why it is a flat line. The phase change "region" I have defined is over 1 degree K between 373.15K and 374.15 K. I only extended it beyond in both directions in case the simulation calculates the temperature past my phase change bounds (perhaps I should extend this region).

 

My questions are:

1) Should I not also be defining tables for thermal conductivity and dynamic viscosity since they too change significantly under the vapor dome? I have done this as follows:

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2) I understand that there will be inaccuracies with this method but I am not clear on how to quantify them. Any explanation as to where the inaccuracies lie if the above table properties have been assigned well?

 

I realize that other software handle phase change but I am interested in Flow only and how best to push the envelopes of its limitations in this capacity.

 

Thanks in advance.

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