SHIRTBUTTON-SIZED GAS TURBINES: THE ENGINEERING CHALLENGES OF MICRO HIGH SPEED ROTATING MACHINERY

Abstract

MIT is developing micro-electro-mechanical systems (MEMS)-based gas turbine engines, turbogenerators, and rocket engines. Fabricated in large numbers in parallel using semicon-ductor manufacturing techniques, these engines-on-a-chip are based on micro-high speed rotating machinery with power den-sities approaching those of their more familiar, full-sized breth-ren. The micro-gas turbine is a 2 cm diameter by 3 mm thick Si or SiC heat engine designed to produce about 10 W of electric power or 0.1 N of thrust while consuming about 15 grams/hr of H2. Later versions may produce up to 100 W using hydrocar-bon fuels. This paper gives an overview of the project and dis-cusses the challenges faced in the design and manufacture of high speed microrotating machinery. Fluid, structural, bearing, and rotor dynamics design issues are reviewed.