Learning Forum

[omar ennaya]

Hello everyone

I wanna calculate the local and average nusselt number in ansys fluent.I wanna make sure how to do this correctly.

I have a triple pipes geometry.

Thanks in advance.

[Rob]

How do you want to define Nu?  Which temperature and heat flux are you using? There are a couple of preset options in the solver, and they're covered in the documentation, otherwise you may want to review Expressions and Custom Field Functions. 

[omar ennaya]

Hello

i don't have heat flux or temperature values as constant.

Well i have a triple concentric/eccentric tubes, the middle one contains a pcm and the inner &the outer tubes contain an HTF.here i'm studying the melting process.

so i wanna calcute the heat transfer coefficient and then the nusselt number.

so i don't know the right way to do this.I know the theory but in fluent no.

thanks. 

[Rob]

Heat flux is available from the Reports menu. There are reset HTC and Nu options, but please read their definitions before use. Both HTC and Nu are artificial values so you need to define what temperatures etc you're calculating against: the default values may not be what you're after. 

[omar ennaya]

Yes this is what makes me confused ...thank you.

if you any documentation or guide report to share it will help.

[Rob]

https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v241/en/flu_ug/flu_ug_fvdefs.html