Sooo, microturbines

[OsoiNA6]

@Boxersix

In reality, only as much as their complexity requires if run within their operating parameters. My knowledge on turbines comes from my dad who before retiring designed alot of the internal bearing and bucket retention parts for GE’s gas and steam turbines, so I guess these smaller micro turbines would be a bit less susceptible to the normal wear of those monsters. Bucket wear and tightness in the hub was the biggest issue, however alot of these new hyper alloys and their derivatives are very tough. Even things like compressed graphite buckets and DLC are making their way into these things for durability. In the steam turbines the biggest issue is bucket wear at the tips, trying to keep them from becoming supersonic in that area. I imagine that these micro turbines utilize one piece turbine wheels(like you’d see in a turbocharger for example) vs individual buckets. These micro turbines run at turbocharger like speeds(50K+ RPM) whereas the larger turbines that make us our daily electricity at the powerplants turn at 3000-3600rpm, so who knows what kind of wear is subjected at that level under continuous use.

The turbines burn at extremely high temps in the combustor and staged sections gas and because of that the likely hood of carbon build up is very low, even if shit fuel is used. They can be made to run very very clean at super high temps, so you could run them on used oil right out of your own car provided it’s filtered enough to not clog the combustor nozzles.

Wear on bucket tips in steam turbines is definitely an issue, but that’s on the low pressure section where you have two things (tall buckets = high tip speeds) and most importantly the steam expansion takes place in the Wilson region where you can have 1-15% moisture depending on exhaust backpressure (and the type of exhaust on the Camaro that rolls by if you are female- but I digress).

The last stage in almost any power generation steam turbine is designed to operate with tip speeds beyond supersonic. Just a function of how large the blade size is since speed is pretty much constant (3600 RPM for 60 Hz markets like the US). The issue is preventing the moisture droplets from wearing the buckets on the inlet side.

Couple countermeasures to this- these include welding hardened stellite to the inlet edge of the blade as well as grooves on some inlet edges to allow the moisture to ride up the groove (from centrifugal force) and then eject outwards. Corresponding drainage grooves are built into the inner casing as well to allow the moisture to exit and go into the condenser.

At the front side (high pressure) end of a steam turbine you will have another kind of erosion but this comes from exfoliation of oxidized scale in the piping from the boiler.

But as you alluded to, the relatively tiny size of the microturbines and controlled operating environment means they aren’t prone to these (and many other) types of issues.

Given the small size I can’t see why the stationary portion (nozzles) on the microturbines can’t be controlled to alter angle and improve efficiency over a range of operating parameters. Something that size, startup and light off shouldn’t take ages, but yeah I’m sure it will require development!