Turbine cooling system temperature
On 30th May I posted that I had been trying to discover the maximum temperature of air inside turbine blades and other parts of the cooling system.
I now have an answer for one type of (high bypass) engine: the air can be 650 to 700 C degrees. This vould be relevant to any discussion about VA going through the engine core, since this is quite close to the suggested melting point of the ash and therefore the ash could at least in theory block the cooling holes in a liquid state. This is presumably more problematic than considering blockages due to solid, very small particles.
The same source suggested that there are also concerns about melted VA hitting the outside of turbine blades after going through the combustor. Some surface chemistry possibilities that do the blade no good, apparently. Again, it's all a question of how much VA......?