Grant: Strategic Projects - Group

The project proposed herein aims at developing enabling technology for waste heat recovery in automobiles, power generation and industrial thermal processes, which typically reject a large fraction of high quality heat (i.e. high temperature) to the atmosphere.  Their efficiency could be improved by converting the waste heat into electricity.  The proposed approach consists of implementing miniature thermodynamic cycles on a chip using microelectromechanical systems (MEMS) technology. The core technology for this concept is the micro steam turbine device, which integrates high speed rotating micro-turbomachinery and electromagnetic machinery to implement the Rankine vapor power cycle in a silicon chip. It is created using microfabrication processing of silicon wafers, such as photolithography, deep reactive ion etching (DRIE), thin film processing, and wafer bonding.   In our previous work, we demonstrated the core rotating components for a Rankine device at low temperature, assisted by external flow control.  This project aims at operating with high temperature steam and achieving self-sustained operation, specifically to: 1) Develop and demonstrate a thermal insulation approach applicable for microfabrication; 2) Understand the conjugate heat transfer and conceive an appropriate device layout; 3) Understand the impact of non-adiabatic flows in the microturbine on its performance and the cycle; 4) Conceive a self-sustained internal secondary flow system, mainly for the bearings; 5) Explore closed-loop operation of the Rankine micro steam turbine.  The activities will be centered on the development of a Hot Rankine test device and will include analytical modeling and numerical analysis of thermal, structural, and fluidic behavior, as well as short loop experiments.