The fluid dynamics of a microturbine system that is applied in a device for chemical and biological analysis—a so-called magic-angle spinning (MAS) probe—is investigated. The drive fluid is pressurized air at ambient temperature provided by nozzles aligned on an intake spiral, driving a Pelton-type microturbine. Computational fluid dynamics (CFD) simulations have been performed and compared with fluid dynamics measurements of the MAS system with 1.3 mm rotor diameter for spinning rates between and . The main optimization criteria of the MAS system are rotor speed and turbine stability and not primarily efficiency, which is standard for turbomachinery applications. In the frame of fabrication tolerances, a sensitivity study has been carried out by varying the nozzles diameter and the nozzle position relative to the rotor. The presented fluid dynamics study of the microturbine system includes the analysis of local fluid flow values such as velocity, temperature, pressure, and Mach number, as well as global quantities like forces and driven torque acting on the turbine. Comparison with the experimental results shows good agreement of the microturbine efficiency. Furthermore, the parameter study of the nozzle diameter reveals optimization potential for this high-speed microturbine system employing a smaller nozzle diameter.
Aerodynamic Optimization of a Microturbine Inserted in a Magic-Angle Spinning System
Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received August 27, 2015; final manuscript received July 5, 2016; published online September 12, 2016. Assoc. Editor: Moran Wang.
Herzog, N., Wilhelm, D., Koch, S., Purea, A., Osen, D., Knott, B., and Engelke, F. (September 12, 2016). "Aerodynamic Optimization of a Microturbine Inserted in a Magic-Angle Spinning System." ASME. J. Fluids Eng. December 2016; 138(12): 121106. https://doi.org/10.1115/1.4034188
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