Broke From United States of America, joined Apr 2002, 1322 posts, RR: 3
Reply 1, posted (12 years 5 months 1 week 6 days 12 hours ago) and read 2545 times:
Sand can have a couple of effects on a turbine engine.
First, the sand can abrade the compressor blades resulting in reduced engine power and eventually compressor stalls due to reduce stall margin or, in extreme cases, blade failure due to the blades being abraded down to very thin airfoils.
The other problem is sand getting into the passages from the compressor that supply cooling air to the turbine vanes and blades. These passages are very small and can be plugged up or the sand can make its way into the blade and vane cooling passages, melt, and cause blade or vane failure due to contamination of the metals or coatings.
Vanes are airfoils that are fixed and blades are airfoils that rotate.
In modern turbine engines, inlet temperatures to the first stage turbine nozzle guide vanes can reach 2500 degrees F at high engine power.
FredT From United Kingdom, joined Feb 2002, 2185 posts, RR: 26
Reply 2, posted (12 years 5 months 1 week 6 days 2 hours ago) and read 2455 times:
Some engines are designed for such conditions though. The CT7 engines of the Apache are, for instance. They have a separator built into the inlet which picks out sand and other FOD from the intake air. On the CT7 equipped aircraft I worked with, the bypass duct sent it all into the oil cooler instead (if the prop and the engine didn’t get that sparrow, the oil cooler would!), but that’s a different story. The fact that the rotor blades of the Apaches can’t take the sand anyway is another different story...
I thought I was doing good trying to avoid those airport hotels... and look at me now.