Reverse flow problem solution

[chowdhuryarijit308]

I am trying to do shell side analysis of a shell and tube heat exchanger in ansys fluent. The heat exchanger also has baffles. I am keeping the tubes at constant temperature and named them solid tubes. Also named the baffles as solid baffles which are adiabatic. In the fluent K-epsilon model is besing used. When I run the fluent, it shows " Reverse flow" in the console and all the plots become constant after some iterations. Why is this happening? Is it because of reverse flow or any other problem? How can I solve this problem?

Please help me with this. Thanks.

[Rob]

What plots become constant? Pictures will help. 

Reverse flow warning is triggered when flow enters the domain from a pressure outlet or leaves via a pressure inlet. It's not an error but you need to review the settings and results to ensure backflow isn't forcing an artificial solution in those regions. 

[chowdhuryarijit308]

[chowdhuryarijit308]

This is the scaled residual plot. Take a look at the energy line. It becomes constant just after a few iterations. It is not converging. Why is this happening? what is the solution? Bellow the convergence criteria I have used are given. Look the reverse flow occurs in the console after 91 iterations and continues till the last iteration. I already have tried by increasing the number of iterations. But it doesnt work. Now how can I solve this?

[chowdhuryarijit308]

Someone pls help me with this issue.

 

[Rob]

And images showing the flow? Those residuals suggest you may have something unexpected in the flow field. But without pictures you'll need to wait for my crystal ball to come back from the cleaners. 

As an aside, bumping on Public Holidays and weekends isn't going to speed up an answer.