berkeman said:
I'll page
@Flyboy since he has lots of practical experience working on jet aircraft. I don't know if he'll be able to help with the design angle, though.
Probably not in the way he's hoping. Lots of basic theory covered in A&P school, but most of the time it's a case of swap the filter after X flight hours, keep the oil topped off, and occasionally sample the oil for spectral analysis. However, lemme dig out the powerplant textbook and see what I can find...
Heyyyy, there's actually a
free PDF of it. Awesome. Chapter 11 covers the lubrication system for turbine engines, but it's an interesting read in gneneral.
Anyways, again, kind of a top level overview of concepts. Lots of dry-sump systems in turbines, because it simplifies part swaps on the accessory gearbox which is basically always on the bottom of the engine. Usually it's well sealed anyways by bearings at the gearbox outputs, with spline drives running the accessories, but sometimes you have to swap out the bearings or seals because of a failure or leak. (I've got an old carbon seal off a Pratt & Whitney PW 306D1 from a swap lying around in a plastic bag somewhere, now that I think about it.)
256bits said:
You just have to now consider the heat exchanger criteria to make it all work out.
It's pretty common to use a fuel/oil heat exchanger. Even after heat soaking on the ground in Arizona in the summer, it's usually cool enough to work as a coolant for the oil, and at altitude, it definitely is cool enough. Warming the fuel actually provides a couple benefits, the biggest being the melting of any ice crystals in the fuel, which is absolutely a thing. I know of at least one airliner that was a write-off after the engines fuel starved on final because the fuel filters got clogged with microscopic ice crystals. But that's a different story.
I don't know how helpful it would be, but the most common brands of aviation oil are Mobil Jet II and Eastman (formerly BP) 2380 turbine oil, with the latter being the most common. (They're actually NOT compatible with each other and require full engine overhauls to switch between them, btw.)
I did find a
tech data sheet for the 2380 oil, which covers some basic mechanical properties like density, kinematic viscosity, pour and flash points, etc. Even goes into how much it makes certain rubbers swell, which is really important. Mobil seems to be a little bit more cagey with their stuff, but I'm sure it's out there.
Hopefully this helps.