Fluids

Fluids

Problem with thermal coating not providing insulation for CFX model

    • Jpret99
      Subscriber

      I am running a simulation of a gas turbine blade with a thermal barrier coating. The model has a hot flowing ga at around 1200 degrees C and 120 m/s. I have modelled the blade and thermal coating using solid elements, however the coating is only 0.4mm thick, so I used a single layer of mesh for it as meshing with more layers produce extremely fine mesh, making the model too large to solve. Upon looking at the results, the blade surface was only 10 degrees Kelvin cooler than the surface of the coating, which based on theory should be at least 370 to 425 degrees Kelvin cooler. So, the model is not performing correctly.

      I have manually input material properties for the blade and thermal coating in CFX pre which is shown in the images. I’m unsure of this is what’s causing the problem, or if it’s because the coating only has a single layer of mesh. Im not sure if it could also be to do with the reference temperature of the material properties, as ive left it as the default 25 degrees C.

      Any help on this topic would be greatly appreciated.

    • Rob
      Ansys Employee
      It's a pretty impressive coating if it'll drop 400K over 0.4mm! Only having one cell may be an issue, but check both the temperature in the gas and also how you're pulling heat out of the blade itself. is the CFX expert, but if you use adaption can you increase the resolution in the near wall (gas side), coating and blade (solid side) to see what effect that has?
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