... and operate at Reynolds numbers of order 300, two orders of magnitude lower than conventional annular seals. The concepts that hold for turbulent flow, large scale annular seals do not apply to micro bearings and the laminar flow regime sets new challenges in the design, implementation and operation of ultra...

...W. Todd Lindsey; Dara W. Childs, Jordan Professorship of Mechanical Engineering Experimental results are compared to predictions for turbulent flow, short ( D = 76.2 mm , L / D = .17 ) , smooth annular seals with converging and diverging axial taper. Results are presented for four geometries...