Multiobjective muffler shape optimization with hybrid acoustics modeling

Abstract

This paper considers the combined use of a hybrid numerical method for the modeling of acoustic mufflers and a genetic algorithm for multiobjective optimization. The hybrid numerical method provides accurate modeling of sound propagation in uniform waveguides with non-uniform obstructions. It is based on coupling a wave based modal solution in the uniform sections of the waveguide to a finite element solution in the non-uniform component. Finite element method provides flexible modeling of complicated geometries, varying material parameters, and boundary conditions, while the wave based solution leads to accurate treatment of non-reflecting boundaries and straightforward computation of the transmission loss (TL) of the muffler. The goal of optimization is to maximize TL at multiple frequency ranges simultaneously by adjusting chosen shape parameters of the muffler. This task is formulated as a multiobjective optimization problem with the objectives depending on the solution of the simulation model. NSGA-II genetic algorithm is used for solving the multiobjective optimization problem. Genetic algorithms can be easily combined with different simulation methods, and they are not sensitive to the smoothness properties of the objective functions. Numerical experiments demonstrate the accuracy and feasibility of the model-based optimization method in muffler design.

Topology design of reactive mufflers for enhancing their acoustic attenuation performance and flow characteristics simultaneously

“…However, the methods proposed on the basis of these investigations can be mainly applied to concentric expansion chamber mufflers, and the obtained optimal mufflers cannot avoid extreme pressure drops, caused by high flow resistance. The work by Airaksinen and Heikkola optimized nonconcentric mufflers, but it did not consider pressure drops. The drawbacks of the previous researches are due to two reasons.…”

Multi-objective Optimization of a Multi-chamber Perforated Muffler Using an Approximate Model and Genetic Algorithm

“…9-11 Airaksinen, et al 12 provided a combined use of a hybrid finite method and genetic algorithm for the multi-objective optimization of various mufflers. However, these optimizations are either limited in use or computationally expensive.…”

Advanced numerical techniques for the acoustic modelling of materials and noise control devices in the exhaust system of internal combustion engines

“…The configuration studied in this section is the first of those shown in Table 3. 4. The temperatures used to compute the corresponding fields, following the scheme of Figure 3.3, are shown in Table 3.…”

“…The configurations of the silencer under study are geometries 1 and 3 of those shown in Table 3. 4. Two extra computations have been carried out for comparison purposes considering geometry 1.…”

“…A perforated dissipative silencer consisting of a perforated central duct surrounded by a chamber with dissipative fibre is depicted in Figure 4. 4. The volumes defining the silencer and its boundary surfaces are denoted as Ω a , Ω m , Γ a and Γ m respectively, whereas the perforated surface is denoted by Γ p .…”