Massachusetts Institute of Technology

Ian A Waitz

Martin Arnold Schmidt

Jeffrey Hastings Lang

Stephen D Senturia

Alan H Epstein

Stuart A Jacobson

Steven F Nagle

Kenneth S Breuer

Fredric F Ehrich

Mark S Spearing

G K Ananthasuresh

K Uno Ingard

Belva J Hayden

Julian Sell

John M Brookfield

The invention overcomes limitations of conventional power and thermodynamic sources by with micromachinery components that enable production of significant power and efficient operation of thermodynamic systems in the millimeter and micron regime to meet the efficiency, mobility, modularity, weight, and cost requirements of many modern applications. A micromachine of the invention has a rotor disk journalled for rotation in a stationary structure by a journal bearing. A plurality of radial flow rotor blades, substantially untapered in height, are disposed on a first rotor disk face, and an electrically conducting region is disposed on a rotor disk face. A plurality of stator electrodes that are electrically interconnected to define multiple electrical stator phases are disposed on a wall of the stationary structure located opposite the electrically conducting region of the rotor disk. A first orifice in the stationary structure provides fluidic communication with the first rotor disk face at a location radially central of the rotor blades, and a second orifice in the stationary structure provides fluidic communication with the first rotor disk face at a location radially peripheral of the rotor blades. An electrical connection to the stator electrode configuration is provided for stator electrode excitation and for power transfer with the stator electrode configuration as the rotor disk rotates.

Microturbomachinery

In the invention, propagating broad band and tonal acoustic components of noise characteristic of interaction of a turbomachine blade wake, produced by a turbomachine blade as the blade rotates, with a turbomachine component downstream of the rotating blade, are reduced. This is accomplished by injection of fluid into the blade wake through a port in the rotor blade. The mass flow rate of the fluid injected into the blade wake is selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake. With this fluid injection, reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved. In a further noise reduction technique, boundary layer fluid is suctioned into the turbomachine blade through a suction port on the side of the blade that is characterized as the relatively low-pressure blade side. As with the fluid injection technique, the mass flow rate of the fluid suctioned into the blade is here selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake; reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved with this suction technique. Blowing and suction techniques are also provided in the invention for reducing noise associated with the wake produced by fluid flow around a stationary blade upstream of a rotating turbomachine.

Reduction of turbomachinery noise

The invention provides a micro-gas turbine engine and associated microcomponentry. The engine components, including, e.g., a compressor, a diffuser having diffuser vanes, a combustion chamber, turbine guide vanes, and a turbine are each manufactured by, e.g., microfabrication techniques, of a structural material common to all of the elements, e.g., a microelectronic material such as silicon or silicon carbide. Vapor deposition techniques, as well as bulk wafer etching techniques, can be employed to produce the engine. The engine includes a rotor having a shaft with a substantially untapered compressor disk on a first end, defining a centrifugal compressor, and a substantially untapered turbine disk on the opposite end, defining a radial inflow turbine. The rotor is preferably formed of a material characterized by a strength-to-density ratio that enables a rotor speed of at least about 500,000 rotations per minute. An annular, axial-flow combustion chamber is provided that is located axially between the compressor and turbine disks and that has a ratio of annular height to axial length of at least about 0.5. The micro-gas turbine engine can be configured with an integral microgenerator as a source of electrical power, and can be employed for a wide range of power, propulsion, and thermodynamic cycle applications.

Growing community of inventors

Newton, MA, United States of America

Ian A Waitz