Learning Forum

[Abubakar]

Hi,

I ran a Heat transfer simulation on a Graphic card but HTC which I got doesn't make any sense below I have shown the results which I got from the simulation.

1. Nusselt number which I got from the simulation

[Rob]

You might want to read the definition of the HTC you're calculating in the manual.

[Abubakar]

Can you send me the link for the same?

[DrAmine]

Just hit F1 if you are in Fluent then go to User's Guide and check the definitions.

[DrAmine]

/forum/discussion/12275/confused-about-surface-nusselt-number-evaluation-in-fluent

[Abubakar]

I have user guide I am searching for the page where the calculation of HTC is explained

[Abubakar]

Please correct me if I am wrong Formula: HTC=q/(T_wall-Tcell)
Fluent use above formula to calculate HTC and I am getting negative HTC coz of q.
If I am correct I should not get NU=0 it should be some negative value, right?

[DrAmine]

Does depend on which HTC you are referring default one us called surface HTC uses reference temperature from reference values.

[Abubakar]

yes I am referring to Surface HTC

[DrAmine]

Then ref temperature is used. Adjust it if you need that

[Abubakar]

Sorry, I didn't get this. Actually, I wanted to know in my case what makes surface HTC negative and If HTC is something Nu should be zero, right?

[Rob]

What is the heat flux through each of the wall and wall:shadow pair?

[Abubakar]

do you want to see contour or an average value will be enough for you?

[DrAmine]

It gets the sign of the heat flux ongoing or outgoing you might take only the absolute as it is a derived quantity. For first case add a screenshot of heat flux report fir the wall and its shadow

[Abubakar]

Heat flux

[DrAmine]

Almost nice. I do not see any issue. Just nusselt number might be not defined fir solid zone. I won't be irritated by htc or nusselt numbers as they are not used at all by the solver.

[Abubakar]

sir & sir thanks for your clarification.

[DrAmine]

Welcome and good weekend

[Abubakar]

same to you!