Design and Manufacture of a Composite Flywheel Press-Fit Multi-Rim Rotor

Abstract

The pre-compression that develops in a press-fit multi-rim rotor suppresses tensile stresses caused by the curing process and high speed rotational centrifugal forces, increasing the overall performance of the flywheel rotor. In this study, the interferences and the rim thickness of up to five rims of graphite/Ep and glass/Ep are analyzed to maximize the specific energy density (SED) of a multi-rim composite flywheel rotor. Three states are considered: (a) cured rims with residual stress prior to press-fitting; (b) a stationary press-fitted rotor; (c) a rotor at maximum rotational speed. Two methods of press-fitting rims are presented. One method has each rim machined with tapered inner and outer rim surfaces. The other method uses a guiding rim to expand the outer rim and guide the inner rim into the expanded outer rim. An optimized multi-rim rotor, composed of one glass/Ep rim and one graphite/Ep rim, is scaled to have energy storage capability of 5 kWh, and is successfully manufactured by machining tapered rims and hydraulic pressing.

Design and Multi-Objective Optimization of Fiber-Reinforced Polymer Composite Flywheel Rotors

“…Alternatively, a press fit may be employed. In [15] two different methods for press fitting are presented. To facilitate press fit assembly, certain rim geometries may be incorporated, see Figure 2.…”

Rim-Rotor Rotary Ramjet Engine, Part 1: Structural Design and Experimental Validation

“…A glued assembly can damp vibration, which is an asset for high-speed turbomachineries and rotordynamics [17,18] and avoid local stress factors associated with fasteners. High voltage is supplied to the engine by using an electric brush in contact with a steel pin pressfitted in the center puck.…”

“…The flex joint is a key element of the design, as its compliance prevents separation of the rim rotor at high speed [19]. The model is based on flywheel, press-fit, multi-rim-rotor models, with the addition of the critical flex joint [18]. The center puck, the electrodes, and the insulator were analyzed separately, as they sustain their own weight and the low stiffness of the insulator uncouples the analysis.…”

Energy Management and Control System Design of an Integrated Flywheel Energy Storage System for Residential Users

“…On the other hand, FESSs are technologically complex, namely they are made up of several mechanical, electromagnetic and electronic components (electrical machine, power electronic converters, sensors, bearings, etc. ), thus requiring expert knowledge in different fields to be designed and manufactured appropriately [22,24,25], this, along with high capital cost, represents the main drawbacks that is still preventing FESS to be widespread, especially for low-medium size applications [20,22].…”