CAREER: NOVEL INTEGRATION OF FLUID DYNAMIC DESIGN INTO ELECTRIC MACHINES

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Energy efficiency and sustainable use of energy continue to be among nations' most pressing challenges as global energy demand steadily increases. In fact, global energy needs will continue to grow steadily into the future. Recent studies indicate that the world's primary energy demand is likely to grow more than 50% by 2030. Among global electric energy needs, compressor systems consume a substantial proportion. The applications for compressors are very broad and useful for humanity from many perspectives. Compressors can be found in very small equipment such as sleep apnea machines, to kilo-Watt level micro-turbines for power generation and heating, ventilation, and air conditioning (HVAC) systems, to mega-Watt level natural gas turbines of power plants. Another useful and sustainable application of compressors is for compressed air energy storage systems. Other applications include prime mover of electrical generation systems, aircraft jet engines, and high-speed propulsion systems. Among all compressor types, axial flow compressors have one of the highest efficiency, and most of the axial flow compressors require electric motors. Hence, there is a need to design electric motors that can run the axial flow compressors at high speed and efficiency at low cost. The motivation of this research aims to develop an advanced electric machine to replace older, inefficient compressor topologies with axial flow compressors, paving the way for more efficient and sustainable energy use. The research proposes a novel and transformative motor, by combining the rotor of the electric motor and airfoil of a compressor into one structure. This approach will reduce the weight, volume, and cost of the axial flow compressor systems and increase the efficiency compared to traditional separate motor and compressor designs. The CAREER project aims to disseminate the research results to university students via credit courses, practicing engineers via short courses, seminars, and tutorials, and the general public via demonstrations and open houses. The project will promote participation of women and under-represented minorities in undergraduate and graduate engineering education to advance equal participation and advance diversity via various workshops and STEM activities such as Camp Badger. The central hypothesis underlying this research effort is that if a rotor of electric machine is shaped as an airfoil, then there will be a conversion of mechanical torque from the rotor to kinetic energy in the fluid, because the rotor will serve as an airfoil for the compressor and compress the gas. Hence, this CAREER research proposes a novel electric machine where the rotor is shaped as an airfoil that achieves both motoring and compressor function. This approach will achieve self-cooling of the rotor and stator due to inherent gas flow, reduction in the axial length of the compressor, simpler and more robust mechanical design due to reduced axial length, and simpler bearing design due to reduced axial length. The research aims to develop a unified theory of electric machines and turbo machinery to integrate the torque production and fluid dynamics. Multi-physics simulations will be performed to analyze the electromechanical, thermal, structural, and fluid dynamic attributes. Performance characteristics will be researched and benefits of the novel integrated rotor-airfoil design will be quantified and compared with traditional separate motor and compressor designs. Finally, a proof-of-concept prototype will be built and tested to validate the design, analytical and simulation results. This transformational research aims to achieve lower weight, volume, and cost, higher efficiency, and higher reliability of next generation high-speed compressor systems. The proposed concept is applicable to and will be investigated for turbines and fans.