tips for Hex mesh of object with cooling pipes

Hi there

I am trying to perform a Hex mesh of the attached model (zipped step file).

hex mesh required.png

The model is a sheet of metal with some cooling channels in it.

Trelis 16.3.3 does not appear to perform a Hex mesh on the model it with the default settings.

Just wondering if anyone has some tips or suggestions for Hex meshing this model

Many thanks
first_wall_with_channels.zip (279 KB)