Nusselt number correlation for tube array with two different tube sizes

[BasakAbhishek]

Hello,

I have a tube array with two different tube sizes. The larger ones are located in a square pitch in a 5x5 arrangement. The smaller ones are located in the centres of the diagonal of the larger ones. If you rotate the assembly by 45 degrees, its clear that both the tubes are arranged in a square lattice. I have to calculate the heat transfer correlation because of cross flow. I wonder if you can point me to any reference for nusselt number for such an arrangement?

 

[pierreick]

Hi,
How significant is the difference in pipe size?
I would consider the total heat transfer area of your pipes and I will determine an equivalent diameter to apply in the calculation of the Nusselt Number.
Pierre

 

[BasakAbhishek]

One is 186mm od and the other is 60mm od..so very different
Abhishek

 

[Latexman]

What is the total heat transfer area of each tube size?

Good Luck,
Latexman

 

[BasakAbhishek]

There are 5x5 number of tubes for the larger size..6x6 of the smaller size..both are 300mm long
Abhishek