[arehman1289]

Hello everybody,

I am designing a counter flow heat exchanger embedded in a phase change material. I am using corrugated pipes instead of plain ones with fins attached throughout the length of the heat exchanger.
It is quite a detailed geometry. I was wondering, normally how do CFD experts model large heat exchangers? Since the whole exchanger would require at least 100-120 million cells to incorporate all the details (about 6*6*6 feet).
I cannot use a plane of symmetry since there isn't one, and I am interested in the transient thermal performance. The two options I had in mind are as follows, but im not sure if they would work:

1. Scaling down the model by e.g. a factor of 10 (but this would result in the same element numbers of the mesh just with smaller sizes). Dont know if it is effective ?

2. Doing only a portion of the exchanger (but no sure which portion to do, since every length in the exchanger would have a different temperature and heat profile). Then somehow finding the thermal parameters per unit length and extrapolating ?

Do I have any other reasonable scientific option ?

Looking forward to your advice, based on your experience for such problems.

Thanks
Abdur

[arehman1289]

please help !!