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Do they really have the labyrinthine cooling passages depicted??
Turbine blade cooling
- Thread starter Let'sgoflying!
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edessa
Pre-takeoff checklist
Yes they do.
Its usually found only on the larger turbo fan engine hot sections so they can run it at higher temps to get more efficiency. I've seen some newer blade designs with 100+ micro holes drilled in them. The smaller turbines usually do not have it.
Let'sgoflying!
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Specifically, the internal U-turns and elbows buried in the structure. Like this one must have been made with sandwiched layers or 3-D printing?
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Velocity173
Yeah, the newer blades are like that. In the old GE 701 it had single pass cooling without those U turns. In the newer 701C it got “serpentine” channels for multi pass cooling. Results, increased blade life with better cooling. Think they used an improved coating film as well.
Larry in TN
En-Route
Some do, some don't. It's obviously less expensive to produce them without the core passages so there's a cost/performance tradeoff.
When they do, a ceramic core, the shape of the desired passages, are placed in the wax injector mold before the wax is injected. The wax then covers the ceramic core. A monoshell coating is applied by dipping in slurries and coating with sand-like material, building up the shell. When dried, the wax is melted out leaving cavities the shape of the desired part. The empty monoshell is pre-heated then the alloy is poured in to form the casting. After cooling, the monoshell is broken off and the ceramic core removed via a caustic bath.
Core passages are also used on vanes (which do not rotate like blades) primarily for weight reduction.
When they do, a ceramic core, the shape of the desired passages, are placed in the wax injector mold before the wax is injected. The wax then covers the ceramic core. A monoshell coating is applied by dipping in slurries and coating with sand-like material, building up the shell. When dried, the wax is melted out leaving cavities the shape of the desired part. The empty monoshell is pre-heated then the alloy is poured in to form the casting. After cooling, the monoshell is broken off and the ceramic core removed via a caustic bath.
Core passages are also used on vanes (which do not rotate like blades) primarily for weight reduction.
The only method I'm familiar with is how GE makes the blade holes. My brother had oversight of a quality program for the manufacture of the blades and the "drilling" of the holes. Look up the Laser MicroJet for more info.
Let'sgoflying!
Touchdown! Greaser!
Now that’s pretty fancy engineering!