DESIGN, FABRICATION AND TESTING OF A HYBRID COMPOSITE FLYWHEEL ROTOR HUB

摘要

This paper describes a hybrid composite fly wheel rotor designed to store 50 kWh energy at maximum rotational speed of 17,000 rpm. Design optimization and stress analysis were carried out to acquire a hybrid composite dome-type hub geometry, thickness and fiber winding angles which provided the required stiffness to match the radial growth and axial contraction of the composite flywheel rotor during high speed rotation. Both the rotor and dome type hub were then fabricated by filament winding process using glass and carbon fiber reinforced composites. The hub and rotor were assembled by press-fitting technique to apply the necessary compression at the composite rotor inner surface, resulting in lowering of undesired radial tensile stress. During press-fit assembly process the hoop strains developed at various locations of the composite dome-type hub were measured using strain gauge sensors, which were found to be in agreement with the analytical predictions. The performance and dynamic behavior of the hybrid composite dome-type hub was verified by conducting a successful spin test of the flywheel rotor up to the target test speed of 17,000 rpm. Wireless telemetry strain measurements up to 9,700 rpm at various locations of the dome-type hub were also in a good agreement with analytical calculations. Moreover, the flywheel rotor temperature increment of 7.2°C (i.e. 24.5°C to 31.7°C) corresponding 1.6 mbar vacuum level was observed during the spin test.