Comparison of various sound models for predicting transmission loss of compressor mufflers based on the modal series expansion method

Abstract

With the rising public awareness and concern for noise control, properly designed mufflers for compressors are now becoming more and more important. Reactive mufflers are commonly used in refrigerating and air conditioning compressors to reduce the gas pulsation generated by the suction and discharge systems. Due to the size limitation and expense of these mufflers, it would be beneficial to predict the transmission loss (TL) characteristics at the design stage. To accomplish this, many methods have been studied, including plane wave method, finite element method (FEM), boundary element method (BEM), and modal series expansion method (MSEM). Three MSEM sound models, that is, point model, surface model, and line model, have been compared on the basis of some criteria, such as accuracy and computation time, in this article. A newly revised point model verified by 3D FEM has been proposed to overcome singularity of a previous point model. The computational accuracy and efficiency of the surface model, the circular line model, and the revised point model has been compared. It is found that the proposed point model not only has higher computational efficiency than that of the circular line and the surface models but also has high accuracy.