I see the term conjugate heat transfer all over the place but can not find a clear explanation of it. I think I have an idea but figured one of you guys could give a better explanation Thanks!

Conjugate Heat Transfer is/refers to............

cht involves heat transfer between a solid and liquid interface.

thanks, can you give an example? would a boiler (old water heaters) be an example?

I think you are just thinking of general convective heat transfer.

It seems that conjugate heat transfer is a specific way of solving convective heat transfer problems. For instance, let's assume air flow over a flat plate. The easiest (but less accurate) way to solve the rate of heat transfer to the plate would be to assume a plate with a constant temperature distribution. We would also probably compute the properties of the air flow using a single given temperature.

In reality the plate has finite dimensions, and the air flow is going to be dependent on the temperature distribution. In turn the temperature distribution in the plate will be dependent on the air flow, and so on. In short - the temperature distribution in each medium is dependent on the other. Obviously you need a fast and efficient solver to solve the problem. It looks like it's CFD (Computational Fluid Dynamics) and Heat Transfer FEA (Finite Element Analysis) in one analysis. Not a trivial problem whatsoever.

This paper from ANSYS (a big FEA software company) should have some good info (I haven't read it myself):

http://www.ansys.com/assets/tech-briefs/cfx-cht.pdf