My design has a few relevant characteristics:
One idea that occurred to me is to:
One non-obvious driver for this is that I have an existing ugly low pressure zone due to some geometry details that it would be nice to fill with some flow; basically taking advantage of a coincidence.
Thoughts about this approach? Is it a horrible idea? Will it fail to cool the engine, or will the drag be overwhelming? Ideas on how to size or adjust it?
- A buried water-cooled turbocharged 180 hp engine, with coolant radiator, oil cooler, and intercooler in a remote cooling duct
- A "firewall box" around the engine forming a plenum, similar to those Stemme uses with their buried Rotax engines (but including the sides)
- An estimated boundary layer thickness at the cooling duct intake of ~1 cm
One idea that occurred to me is to:
- Have a boundary layer extractor inlet, a separately-routed section of the inlet comprising the 2 cm or so closest to the fuselage, rather than a boundary layer diverter or just ingesting the boundary layer into the cooling duct
- Run the plenum at slight negative pressure to "suck in" the boundary layer through the extractor inlet
- Achieve this negative pressure by having an appropriately sized exit (130% of extractor inlet area?) at a convenient negative pressure zone
- If necessary, augment this negative pressure with a small exhaust fan
- If desired, have the entrance from the extractor inlet into the plenum incorporate blast tubes to cool problematic points
One non-obvious driver for this is that I have an existing ugly low pressure zone due to some geometry details that it would be nice to fill with some flow; basically taking advantage of a coincidence.
Thoughts about this approach? Is it a horrible idea? Will it fail to cool the engine, or will the drag be overwhelming? Ideas on how to size or adjust it?
