it might be use full that you can have a setting, maybe through the console to make a powder or a liquid go through a solid or another powder or liquid with out affecting any thing except taking heat?

think of it like making water go through brick and taking its heat

it might be too hard to put but just seeing if its possible

and if you want to set multiple collisions you can always do it separability like with PIPE

kind of,

also this could be use full for separators or cooling systems!

Yep though it will retain its properties

well lets that works but maybe for example i want to flow water through a box of DMND with coal burning in it

the DMND nothing will work its just you cant make the particle go through the box that has burning coal