Application of Specialized FEA Dynamic Modeling Techniques for Noise Reduction of Superchargers

A simulation methodology for dynamic modeling of geared rotor systems such as superchargers was used for determining the housing vibration response. The approach provides an ability to make quick parametric design modifications to the model for evaluation of relative noise response with the assumption that the averaged housing vibration level correlates approximately to the noise radiating from the surface. The housing in some cases was modeled as a lumped mass representation for efficiency, and when higher accuracy of housing modes was needed, a detailed flexible Finite Element Analysis (FEA) representation was used. The interesting features of the methodology were the use of constraint equations to model the gear mesh response per unit Transmission Error (TE) input, along with summarizing the component kinetic and strain energy for each mode and the mesh compliance for fast evaluation of opportunities for noise reduction. It should be noted that gear transmission error is the main source of noise for these studies. For the supercharger application, evaluation of several potential design modifications, such as adding a clutch, comparing helical versus spur gears, and bearing alterations are presented.