Heat exchanger topic F value 1

[AO1958]

Hello there

I am dealing with a plate fin and tube heat exchanger.

From classic thermodynamics I know that if the counterflow is perfect, I would have following equation

Q = UA*LMTD

In case of not perfect counterflow, I shall multiply for the F factor

Q = UA*F*LMTD

Let's consider a case when I have a mixed configuration - part counterflow, part crossflow -.

Please is there a formula in order to determine this F factor ?
Or do you know any literature reference I can have a look at ?

I have tried to read all post but I think there isn't any concerning this specific topic.

Many thanks

 

[ione]

Is your configuration anything similar to one of those reported in the attachment?

 

[MrBTU]

Look at the LMTD correction factor charts in your TEMA standards book, and if needed, break up the unit into two sections and calculate the correction factor separately for each section.