- Blisk
A blisk is a single-engine component composed of a
rotor disc and blades through machining from a solid piece of material or by welding individually manufactured blades to the rotor disc. The term is used mainly inaerospace engine design. Also known as an "integrally bladed rotor" or IBR.History
Blisk manufacturing has been in steadfast for the past 20 years. It was first in ww2
Advantages
Instead of making the compressor disks and then attaching the blades later on in the process, blisks are just single elements combining the two. This removes the need to attach the blades to the disk (via screws, bolts, etc) and thus decreases the number of components within the compressor while at the same time decreasing drag and increasing efficiency of air compression within the engine. In addition, the removal of the dovetail attachment that is found on traditional turbine blades eliminates a common source for crack initiation and subsequent propagation.O. Younossi, et al., Military Jet Acquisition: Technology Basics and Cost-Estimating Methodology,
RAND Corporation , ISBN 0-8330-3282-8, p. 29-30 (2002).]Disadvantages
Any damage to IBR blades beyond minor dents requires the full removal of the engine so that the IBR may be replaced or, if possible, replacement blades welded on. Maintenance of this nature can not be done on the flightline and often must be performed at a specialized facility. IBR blades must undergo rigorous harmonic vibration testing as the natural damping of the dovetail attachement of a typical turbine blade is no longer present.
Process
Blisks can either be
CNC milled,ECM manufactured or welded together. Viaelectro chemical machining , three stages must be undergone in order to produce the final product.Notes
References
* [http://www.sae.org/aeromag/techupdate_4-00/14.htm] Rolls-Royce LiftFan blisk [March 2003] [http://100.rolls-royce.com/facts/view.jsp?id=283]
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