Radial Wave Rotor (Wave Disc)




Traditional attempts to use depressions or pockets to control wave reflection of off-design operation in internal combustion engines undesirably reduce the sensitivity of axial wave rotors to engine speed changes. Nevertheless, there still exists a need to improve the performance and reduce the size of traditional wave rotors to enhance their commercial viability or adapt a different geometry for more convenient implementation.


Description of Technology 


Michigan State University’s invention uses an axial wave rotor as a supercharger in internal combustion engines for automotive vehicles. The wave rotor apparatus, which has an igniter and fuel injector, includes fluid passageways oriented in a direction offset from its rotational axis and employs stacked layers of generally radial channels. Turbomachinery is located internal and/or external to the wave rotor, reducing undesirable pressure losses caused by conventional collectors and/or diffusers. The correctional passageways advantageously achieve directed and self-actuated aerodynamic control of the internal flow and shock wave pattern, and scavenging processes are also improved by the use of centrifugal forces.


Key Benefits

  • Advantages over conventional devices: The radial wave rotor should produce higher power densities, an improved efficiency, a smaller frontal area, and a smaller size compared to know axial wave rotors. Performance is simpler to model, predict, and analyze in the design stage than traditional wave rotors.
  • Improved flow scavenging and compression: The centrifugal forces of the fluid created by the invention advantageously improve flow scavenging and compression.
  • Less expensive to manufacture: The offset or generally radial passageways in the invention are easier and less expensive to manufacture as compared to many traditional, axial wave rotors, especially if incorporated into a layered arrangement.
  • Improved cycle timing: The stacked configuration and/or shapes of channels provide advantageous variations in cycle timing.




The invention has applications as a supercharger in internal combustion engines for automotive vehicles. Wave rotors have also been proposed for use in propulsive jet engines and power turbines.


Patent Status


U.S. patent issued 7,555,891




Norbert Mueller, Janusz Piechna, Pejman Akbari, Florin Iancu


Tech ID




Patent Information:


For Information, Contact:

Brian Copple
Technology Manager
Michigan State University