Multi flow in two different domain
 

I want to do simple concentric heat exchanger proplem so i created one fluid surface for inner flow and one solid surface for pipe thickness and another fluid surface for outer flow and meshed.

then import the mesh in cfx and created innerflow domain as fluid domain and given material as "Air at ideal gas"
pipe thickness as solid domain and given material as "Stainless Steel"
then i give outerflow as fluid domain and material as Water,
what happened for innerflow also it taken as water, suggest me how to handle this problem
i want to give two different fluid for two different domain

In "Case Options > General" turn off "Constant Domain Physics".

Same Problem
 

Still I didnt get that one

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