scholarly journals Noise Elimination of a Multi-tone Broadband Noise with Hybrid Helmholtz Mufflers Using a Simulated Annealing Method

2012 ◽  
Vol 37 (4) ◽  
pp. 489-498 ◽  
Author(s):  
Min-Chie Chiu
Keyword(s):  
Simulated Annealing ◽  
Shape Optimization ◽  
Noise Reduction ◽  
Noise Level ◽  
Pure Tone ◽  
Helmholtz Resonator ◽  
Broadband Noise ◽  
Simulated Annealing Method ◽  
Machine Room ◽  
Annealing Method

Abstract Noise control is essential in an enclosed machine room where the noise level has to comply with the occupational safety and health act. In order to overcome a pure tone noise with a high peak value that is harmful to human hearing, a traditional reactive muffler has been used. However, the traditional method for designing a reactive muffler has proven to be time-consuming and insufficient. In order to efficiently reduce the peak noise level, interest in shape optimization of a Helmholtz muffler is coming to the forefront. Helmholtz mufflers that deal with a pure tone have been adequately researched. However, the shape optimization of multi-chamber Helmholtz mufflers that deal with a broadband noise hybridized with multiple tones within a constrained space has been mostly ignored. Therefore, this study analyzes the sound transmission loss (STL) and the best optimized design for a hybrid Helmholtz muffler under a space- constrained situation. On the basis of the plane wave theory, the four-pole system matrix used to evaluate the acoustic performance of a multi-tone hybrid Helmholtz muffler is presented. Two numerical cases for eliminating one/two tone noises emitted from a machine room using six kinds of mufflers (muffler A~F) is also introduced. To find the best acoustical performance of a space-constrained muffler, a numerical assessment using a simulated annealing (SA) method is adopted. Before the SA operation can be carried out, the accuracy of the mathematical model has been checked using the experimental data. Eliminating a broadband noise hybridized with a pure tone (130 Hz) in Case I reveals that muffler C composed of a one- chamber Helmholtz Resonator and a one-chamber dissipative element has a noise reduction of 54.9 (dB). Moreover, as indicated in Case II, muffler F, a two-chamber Helmholtz Resonator and a one-chamber dissipative element, has a noise reduction of 69.7 (dB). Obviously, the peak values of the pure tones in Case I and Case II are efficiently reduced after the muffler is added. Consequently, a successful approach in eliminating a broadband noise hybridized with multiple tones using optimally shaped hybrid Helmholtz mufflers and a simulated annealing method within a constrained space is demonstrated.

scholarly journals Numerical assessment of two-chamber mufflers hybridized with multiple parallel perforated plug tubes using simulated annealing method

2017 ◽  
Vol 36 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Min-Chie Chiu
Keyword(s):  
Simulated Annealing ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Global Optimum ◽  
Broadband Noise ◽  
Optimization Process ◽  
Sound Transmission Loss ◽  
System Matrix ◽  
Simulated Annealing Method ◽  
Annealing Method

Enormous effort has been applied to research on mufflers hybridized with a single perforated plug tube; nonetheless, mufflers conjugated with multiple parallel perforated plug tubes that disperse venting fluid and reduce secondary noise have been overlooked. To this end, an analysis of the sound transmission loss of two-chamber mufflers with multiple parallel perforated plug tubes that are optimally designed to perform within a limited space will be presented. Here, using a decoupled numerical method, a four-pole system matrix for evaluating acoustic performance (sound transmission loss) is derived. During the optimization process, a simulated annealing method, which is a robust scheme utilized to search for the global optimum by imitating a physical annealing process, is used. Prior to dealing with a broadband noise, the sound transmission loss’s maximization relative to a one-tone noise (200 Hz) is produced to check the simulated annealing method’s reliability. The mathematical model is also confirmed for accuracy. To understand the acoustical effects brought about by the various tubes (perforated tubes, internally extended non-perforated tubes, and non-perforated tubes), mufflers with internally extended non-perforated tubes and non-perforated tubes have been evaluated. The optimization of three kinds of two-chamber mufflers hybridized with one, two, and four perforated plug tubes have also been compared. The results are revealing: the acoustical performance of mufflers conjugated with more perforated plug tubes decreases as a result of the decrement of the acoustical function for acoustical elements (II) and (III). Accordingly, in order to design a better muffler, an advanced presetting of the maximum (allowable) flowing velocity is necessary before an appropriate number of perforated plug tubes can be chosen for the optimization process.

scholarly journals Shape Optimization of a Labyrinth Seal Applying the Simulated Annealing Method

2004 ◽  
Vol 10 (5) ◽  
pp. 365-371 ◽  
Author(s):  
V. Schramm ◽  
J. Denecke ◽  
S. Kim ◽  
S. Wittig
Keyword(s):  
Simulated Annealing ◽  
Shape Optimization ◽  
Optimization Method ◽  
Labyrinth Seal ◽  
Local Optima ◽  
Simulated Annealing Method ◽  
Flow Solver ◽  
Gradient Based ◽  
Computational Fluid Dynamics Cfd ◽  
Annealing Method

In the present work, an environment for the shape optimization of a labyrinth seal is described. A program for a parameterized, automated grid generation is coupled with a commercial Computational Fluid Dynamics (CFD) flow solver and an optimization algorithm. Standard optimization strategies, like gradient-based methods, mostly are trapped to local optima. Therefore, the simulated annealing method is applied. It allows the finding of global minima or maxima of arbitrary functions.The presented optimization method is used to minimize the leakage through a three-finned, stepped labyrinth seal. For the optimization, the step position and the step height are chosen to be variable. The characteristics of the flow fields of selected seal configurations are compared and discussed against the background of the leakage behavior of the seal.

A simulation study of self-assembly of ABC star terpolymers confined between two parallel surfaces

Soft Matter ◽  
2021 ◽  
Author(s):  
Zhiyao Liu ◽  
Zheng Wang ◽  
Yuhua Yin ◽  
Run Jiang ◽  
Baohui Li
Keyword(s):  
Simulated Annealing ◽  
Phase Behavior ◽  
Phase Diagrams ◽  
Simulation Study ◽  
Self Assembly ◽  
Simulated Annealing Method ◽  
Parallel Surfaces ◽  
Annealing Method

Phase behavior of ABC star terpolymers confined between two identical parallel surfaces is systematically studied with a simulated annealing method. Several phase diagrams are constructed for systems with different bulk...

Component Rearrangement on Printed Wiring Boards to Maximize the Fundamental Natural Frequency

1993 ◽  
Vol 115 (3) ◽  
pp. 312-321 ◽  
Author(s):  
Tien-Sheng Chang ◽  
E. B. Magrab
Keyword(s):  
Simulated Annealing ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Printed Wiring Board ◽  
Computationally Efficient ◽  
Additional Increase ◽  
Simulated Annealing Method ◽  
Fundamental Natural Frequency ◽  
Rearrangement Algorithm ◽  
Annealing Method

A methodology to attain the highest fundamental natural frequency of a printed wiring board by rearranging its components has been developed. A general two-dimensional rearrangement algorithm is developed by which the rearrangement of the component-lead-board (CLB) assemblies is performed automatically for any combination of equal size, unequal size, movable and immovable CLBs. This algorithm is also capable of incorporating two design restrictions: fixed (immovable) components and prohibited (non-swappable) areas. A highly computationally efficient objective function for the evaluation of the automatic rearrangement process is introduced, which is a linear function of the size of the individual CLBs that have been selected for each interchange. The simulated annealing method is adapted to solve the combinatorial rearrangement of the CLBs. Using 61 combinations of boundary conditions, equal and unequal sized CLBs, movable and immovable CLBs, various CLB groupings and sets of material properties, it is found that, when compared to the exact solution obtained by an exhaustive search method, the simulated annealing method obtained the highest fundamental natural frequency within 1 percent for 87 percent of the cases considered, within 0.5 percent for 72 percent of the cases and the true maximum in 43 percent of them. To further increase the fundamental natural frequency the introduction of a single interior point support is analyzed. Depending on the boundary conditions an additional increase in the maximum fundamental natural frequency of 44 to 198 percent can be obtained.

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