Here’s an interesting project: a tesla turbine built from old hard drives that’s capable of spinning at up to 15,000rpm. To build your own, you’ll need a few broken hard drives, stock material (aluminum/acrylic), milling machine w/rotary table, and a lathe w/4 jaw chuck. Video clip after the jump.
A regular blade turbine operates by transferring kinetic energy from the moving fluid to the turbine fan blades. In the Tesla Turbine, the kinetic energy transfer to the edges of the thin platters is very small. Instead, it uses the boundary layer effect, i.e. adhesion between the moving fluid and the rigid disk