heat transfer in a pipe flow
 

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.

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

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.

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