Heat Transfer between 2 solids with OptiStruct

Hi,

I am new doing heat transfer analysis with OptiStruct, and I need to solve the following problem:

2 coaxial cylinders (see image below)

The inner Surface of the external cylinder (blue) is generating a heat flux, which makes to increase the internal cylinder temperature (by convection). 

I need to know the temperature of the small cylinder (yellow) and I don´t know how to proceed to solve this kind of problems.

What are the guidelines to solve this problem? 

Thanks in advance!

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