Acoustics module application gallery examples comsol. Comsol multiphysics tutorial absorptive muffler acousti. The sound level from a car depends to a great extent of the quality of the muffler. Efficiently calculating the acoustic transfer impedance of a. Understanding muffler design and sound absorption strategies. Cfd software for simulating fluid flow applications. The absorptive muffler designer simulation app is used for studying and designing a simple resonant muffler with a porous lining. In both cases, when meshing these models, automatic mesh refinement resolves the shock pattern by refining around the regions with very high velocity and pressure gradients. A simulation app made to run on comsol multiphysics software. Learn about different techniques for representing a perforate and a method that makes it simple to compute its acoustic transfer impedance. Absorptive muffler comsol multiphysics modeling software. In his keynote talk at the comsol conference 2018 lausanne, andri bezzola of. Contact comsol official site of comsol multiphysics.
This model describes the pressure wave propagation in a muffler for an internal combustion engine. Popular free alternatives to comsol multiphysics for windows, linux, mac, web, gnu octave and more. Application areas include speakers, microphones, hearing aids, and sonar devices, to name a few. Comsol multiphysics alternatives and similar software. Mufflers are used to attenuate noise emitted by a combustion engine, for example, and should typically perform well in a specific frequency range.
Pdf muffler design with baffle effect and perforations on. Acoustics and vibrations analysis event on thursday, aug, 2015 02. The acoustics module is designed specifically for those who work with devices that produce, measure, and utilize acoustic waves. The most popular versions among comsol multiphysics users are 4. The purpose of the model is to show how to analyze both inductive and resistive damping in pressure acoustics as well as coupling the fluid to the surrounding elastic shell structure of the muffler. Comsol multiphysics is compatible with windows xp7810 environment, 32 and 64bit versions. Experimental results have been obtained using the twomicrophone acoustic pulse method. Review paper on design and development of muffler to optimize. Some of the distinct advantages i have experienced are. Simply log in and follow the onscreen product download directions. It is easy to download the latest version of the comsol software if you have a comsol access account with your license number linked to it. A typical absorptive muffler consists of a straight, circular and perforated pipe that is encased in a larger steel housing. Automotive applications such as mufflers and car interiors. See how your muffler design changes affect the mufflers attenuation performance.
Jun 17, 2015 acoustics pressure analysis with comsol software. The following excerpt from comsol news 2016 spotlights nasas use of multiphysics simulation in optimizing the acoustics of rocket propulsion systems, entitled multiphysics software models. Noise control can be addressed in muffler design, sound barriers, buildings, and room acoustics applications. Acoustic performance design of automotive muffler comsol. Smith plots are useful for relating complex valued sparameters reflection coefficients to input impedance, or to admittance of antennas, transmission lines, and other network components. Comsol multiphysics tutorial absorptive muffler acousti 209. Wed love to hear from you by phone, email, or web inquiry. Comsol multiphysics software, how, by using rigid panels of absorbent material, and their optimized placement, achieve a smoother frequency response without losing bass performance.
Absorptive type mufflers use absorptive materials to. In addition to using multiphysics modeling for your own projects, you can also turn your models into simulation applications and. There are thus two physics involved in the simulation, the acoustic shell interaction and pressure acoustics, both in the frequency domain. Pdf effects of chamber perforations, inlet and outlet. Attenuation is measured through transmission loss, which gives the damping in db as a function of frequency. It uses a general approach for analysis of damping of the propagation of harmonic pressure waves. Absorptive mufflers are designed so that the sound entering the muffler interacts with packing material and is converted to heat by the frictional process. Meeting design challenges with multiphysics simulation. For a comprehensive analysis, use the comsol multiphysics software and the acdc module to see how multiple physics affect your design. You can use the specialized features to visualize acoustic fields and build virtual. Contact comsol, the makers of comsol multiphysics software.
This application is an example of a dynamic specification sheet for a given muffler model. I am looking for a free not only as in freedom alternative to comsol multiphysics. Loudspeakers, sound absorption, standing waves, frequency response, vented loudspeaker cabinet. You will experience speedup by a factor of up to ten in software responsiveness, as well as new and improved features for solving, meshing, and the physicsbased addon modules. Sound waves are reduced as their energy is converted into heat in the absorptive material. How to set up and run a simulation with comsol multiphysics a proper introduction on how to set up and run a model in comsol multiphysics is essential when learning how to use the software. Over the years, researchers in the car industry have struggled to produce mufflers that are efficient from both an acoustic and an environmental perspective. The comsol software automatically formulates the energy equation coupled to the momentum and mass balance equations for ideal gases. Dec 15, 2015 the absorptive muffler designer is used for studying and designing a simple resonant muffler with a porous lining. The software described in this document is furnished under a license agreement. Results of the transmission loss of each muffler obtained from the finite element models are presented. Comsol multiphysics is a crossplatform finite element analysis, solver and multiphysics simulation software. To help the learning process, there is a streamlined. Pdf muffler design with baffle effect and perforations.
The comsol multiphysics geometry and cad environment 320. Absorptive muffler with shells comsol multiphysics. The model is inspired by two existing demonstrations for the acoustic package, the loudspeaker driver in a vented enclosure and the absorptive muffler. Most electromagnetic components, devices, and products are affected by another branch of physics, whether it be heat transfer, structural mechanics, or acoustics, to name a few. Comparative study of the muffler modifications helps to determine the best design type for noise reduction, taking into consideration the effect of the design on fuel economy.
Warning your internet explorer is in compatibility mode and may not be displaying the website correctly. Mufflers are used to attenuate noise emitted by a combustion engine, for example. In this experiment a cad model of automotive muffler is designed using commercial cad software. For example, the new release includes a new app editor tool, graphical updates for running apps and more control over what the apps can do. Popular alternatives to comsol multiphysics for windows, linux, mac, web, gnu octave and more. This muffler s performance relies on absorption by the packing material for performance.
Comsol is one of the best software to date for multiphysics applications. It allows conventional physicsbased user interfaces and coupled systems of partial differential equations pdes. Effects of chamber perforations, inlet and outlet pipe diameter variations on transmission loss characteristics of a muffler using comsol multiphysics december 2019 doi. The transmission loss for the muffler was analyzed using nastran, ansys and comsol software. When you are ready to update your software, click on the download version 5. The model is solved in the frequency domain and provides efficient damping in a frequency range of 100 hz. An evaluation of current commercial acoustic fea software for.
The version of lmgrd must be the same or higher than the flexnet version used by the comsol software. This software was originally produced by comsol ab. Comsol provides an ide and unified workflow for electrical, mechanical, fluid, acoustics and chemical applications. With the app, you can perform an analysis of both inductive and resistive damping in a muffler of your choosing. Note that many of the examples featured here can also be accessed via the application libraries that are built into the comsol multiphysics software and. The app allows users to calculate the transmission loss and acoustic pressure in an absorptive muffler for automotive use. Comsol multiphysics is a generalpurpose simulation software for modeling designs, devices, and processes in all fields of engineering, manufacturing, and scientific research. This might be a question better suited for the software recommendations side of s. This model simulates the pressure wave propagation in a muffler for a combustion engine.
An improved loudspeaker frequency response by using a. This means that the comsol license server needs to be upgraded to comsol 5. It is very easy to learn provided one must know the underlying theory behind the simulation, i. Design modification and acoustic analysis of silencer for.
Absorptive muffler designer app comsol multiphysics. Comsol multiphysics tutorial absorptive muffler acoustics. Absorption and glass pack mufflers holley performance. Pdf effects of chamber perforations, inlet and outlet pipe. Comsol, comsol multiphysics, comsol reaction engineering lab, and femlab are registered. These devices have acoustical applications in the automotive and hvac industries.
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