DESIGN OF AN ENCLOSURE FOR A PORTABLE GENERATOR

Abstract

A simple, effective design for enclosing portable generators to reduce the radiated noise is an idea that seems to be desired by the consumers in the market. This thesis is to determine the feasibility of producing such an enclosure for a generator. Several engineering aspects are incorporated in the design of the enclosure. The first, and probably the most paramount, are the acoustical effects of the enclosure itself. The study follows the theories for insertion loss of a close fitting enclosure. The thesis examines the system behavior of a close fitting enclosure that most acoustic textbooks ignore and how the material stiffness, density and source-to-enclosure distance affect the insertion loss and effectiveness of the enclosure. Measured and theoretical sound pressure level around the generator before and after the application of the enclosure are presented using standards described by ISO© standard 3744. The second important consideration for the. enclosure design involves the heat transfer characteristics. The requirements of cooling air to the generator are discussed. Also presented are some acoustic design considerations to prevent any "direct line of sight" to any of the necessary openings, which will help in the overall insertion loss. The optimization method used in this work is Genetic Algorithm. This method solved for the optimum material properties, panel thickness and enclosure dimensions depending on the noise spectrum and the desired weighting parameters