Impulse noise reduction of household refrigerators using Tabuchi method

Impulsive-type noise generated in household refrigerators due to stick-slip phenomena along with thermoeleastic characteristics are investigated. As a noise reduction countermeasure, a design technnique employing Taguchi methods is proposed. Due to its phenomenological and thermoelastic characteristics, impulse noise in household refrigerator is also referred to as contraction-expansion noise. In order to investigate the source of impulse noise, measurements of the sound pressure levels (and their distribution) generated by the refrigerator under consideration are made in an anechoic chamber. Measurement results indicate that the impulse noise is irregularly generated from the inner parts of the refrigerator, such as shelves and baskets, and most of the noise is from the inner parts in the freezing space. Noise generation factors are also investigated through experiments regarding friction among materials used in the refrigerators. In light of investigations, a design method to reduce the impulse noise with Taguchi techniques is proposed and the overall performance is evaluated. Furthermore, it is noted that the design method is shown to be a viable solution to the design of household refrigerators for friction-induced noise produced mainly by the thermoelastic phenomena.