The anechoic assumption has long been used for the modeling of long exit pipes or ducts of acoustic elements [1, 2, 3, 4, 5, 6, 7]. Especially in compressor discharge line modeling, the exhaust pipe from the compressor manifold leading all the way to the condenser is usually assumed to be anechoic since it is very long. Also, experimental efforts have been made by investigators using different ...

Perforated mufflers are widely used in automotive intake and exhaust systems and need to be properly designed. However, multi-objective optimization in practical perforated muffler designs usually involves finite element or boundary element models, which demand a higher computation time for evolutionary algorithms. In this paper, an approximate model for transmission loss (TL) predictions is es...

The discharge muffler of the rotary compressor is used to reduce the discharge noise produced by pressure pulsations. In order to obtain the transmission loss of discharge muffler, four microphone experimental devices used to measure the transmission loss of the muffler is established. The device is based on the transfer function method on the assumption that there is only plane wave in the tub...

The optimization approach of maximal STL (sound transmission loss) and muffler dimension under space constraints within a building or machine room is fully addressed throughout the graphic analyses as well as the computer-aided numerical assessments in this paper. The primary set of design data is derived by the computer graphic analysis on sensitivity, and the successive algorithm of iteration...

The aim of this paper is to present the numerical resolution of suction muffler configurations (by means of a tridimensional, unstructured, parallel and object oriented CFD&HT TermoFluids code (Lehmkuhl, et al. 2007) specially adapted to low Mach models (Lopez et al. 2012), coupled with the numerical resolution of the whole compressor domain (by means of a modular, unstructured and object orien...

The acoustic behavior of perforated dissipative circular mufflers with empty extended inlet/outlet is investigated in detail by means of a two-dimensional (2D) axisymmetric analytical approach that matches the acoustic pressure and velocity across the geometrical discontinuities, and the finite element method (FEM). The complex characteristic impedance, wavenumber, and perforation impedance are...

Due to increase in the number of goods carrying tricycles, the amount of noise and pollution on our roads has increased. To optimize the control of the engine noise emission for tricycle, different absorptive material liners have been introduced into muffler design. In this study, the performance of Aerogel, Ceramic, Kenaf fibre, Polyester and Rockwool as absorptive material liners on the trans...

The exhaust system has a number of requirements to fulfil. The major ones are to reduce the noise level created by the engine, to channel the waste gases out the rear of the automobile, to minimize the reduction in engine performance, and to have an acceptable service life and cost1. The exhaust system is divided into two main parts, the hot end and the cold end. The components comprising the h...