DESIGN OF PLYWOOD AND PAPER FLYWHEEL ROTORS.

摘要

Technical and economic design factors of cellulosic rotors are compared with conventional materials for stationary flywheel energy storage systems. Wood species, operation in a vacuum, assembly and costs of plywood rotors are evaluated. Wound kraft paper, twine and veneer rotors are examined.; Two hub attachments are designed. Support stiffness is shown to be constrained by the material strength, rotor configuration and speed ratio.; Plywood moisture equilibration during manufacture and assembly is critical. Disk shaping and rotor assembly are described. Winding paper rotors on a lobed cylindrical hub also appears straightforward. Potential self-centering dynamic balancing methods and equipment are described.; Detailed measurements of the distribution of strengths, densities and specific energy of conventional Finnish Birch plywood and of custom made hexagonal {lcub}0,(+OR-)60{rcub} Birch plywood are detailed. Quality control during manufacture significantly narrows the strength distribution and increases the duration of load. Vacuum drying plywood equilibrated at 50% relative humidity produced a significant drop in strength of 5% to 20%.; High resolution tensile tests were performed while monitoring the acoustic emissions with microprocessor controlled data acquisition. Reasonable correlations exist between the instantaneous sample stiffness during the test and the accumulated acoustic energy released in fracture of the sample. They indicate promise for short term monitoring of damage during tensile tests.; Preliminary duration of load tests were performed on vacuum dried hexagonal Birch plywood. Dynamic and static rotor-hub fatigue equipment are designed. Moisture loss rates while vacuum drying plywood cylinders were measured, and the radial and axial diffusion coefficients were evaluated. Diffusion coefficients of epoxy coated plywood cylinders were also obtained.; Economics of cellulosic and conventional rotors were examined. Plywood rotor manufacturing costs were evaluated. The optimum economic shape for laminated rotors is shown to be cylindrical. Vacuum container costs are parametrically derived and based on material properties and costs. Containment costs are significant and are included in comparisons. The optimum design stress and wound rotor configuration are calculated for seventeen examples. Plywood rotors appear to be marginally competitive with steel hose wire or E-glass rotors. High performance oriented draft paper rotors potentially provide the lowest energy storage costs in stationary systems.