[aun.ali]

My simulation shows temp contours as in pic1. but it should be like pic2. please guide, what's the problem with my simulation?why heat transfer did't show in inner tube.

[AlexanderZ]

you should have coupled boundary condition on walls between zones.
It can be done:
1. automatically->
in design modeler both zones should be in one part.
in that case shadow wall will be created automatically on the boundary between fluid and solid zone.
2. manually.->
in that case you have interfaces in your model. create interface between solid and fluid zone, define coupled boundary condition

[aun.ali]

thanks Alexander. manually i defined interfaces and applied coupled wall in mesh interfaces. after that i got 4 walls ( top 4 mentioned in the pic). now the problem is that in which wall will i define heat flux ?. in my condition i applied flux in the shadow wall and a-wall-1-1.

[AlexanderZ]

between zone 1 and zone 2 you may have interface or wall with shadows not both
in addition
you may have heat flux boundary condition or coupled boundary condition