Help pls! Transpiration cooling
 

Hi there

I'm new here and I'm making this thread as the title says - for help.

I'm trying to model transpiration cooling process within combustion chamber walls. There is a hot gas section between two porous walls. The hot gases velocity at inlet is about 50 m/s and their temperature about 1800K. Over the higher wall and under the lower wall there are two cooling air sections (velocity=13 m/s, temp=573.15K). There is a pressure difference between the sections which should be about 0.1 atm.

The problem is - when I'm increasing the porosity of the walls - the wall temperature on the hot gases side is increasing and I think it should act in the opposite way :/

Does anyone have any idea why doeas it act like that?

I need to make this application for my engineer diplom so the case is pretty urgent.

Thank You for any usefull responses.

OK - so after including radiation model it is better - the temperature of porous wall is lower than the temperature of the solid wall but still - with increasing porosity, temperature of the wall on the hot gases side is increasing to... Can anyone tell me why it's like that and what to do to change it?