Silencer simulation cfd silencer cfd simulation muffler simulation muffler cfd simulation aeroacoustics aerodynamics pressure loss

In case of a Silencer Simulation we are mostly interested in gas flow pressure loss, temperature distribution and acoustic behavior. High performance clusters make running computationally expensive aeroacoustic simulations possible. Exhaust silencer simulation services from CFD Freelancing covers both flow analysis and acoustic prediction of your mufflers.

There are two key aspects when designing a silencer or muffler: aerodynamics and aeroacoustics ( or acoustics). Both processes in an exhaust system can be very well simulated by using CFD technology, yet very few companies leverage this technologies.

Silencer and Muffler Aerodynamics

When considering the aerodynamics of a muffler, we are mostly concerned about the pressure loss or backpressure it has to the upstream devices. In case positive displacement blowers, Roots blowers, internal combustion engine silencers, this is an important aspect.

Designing the silencer is although not that easy, if we want to have an optimal operation. This is where CFD comes in. Computational Fluid Dynamics shows us the potential optimization potential in our design, such as:

  • separations
  • high velocity “choke” flows
  • turbulence and strain regions
  • critical pressure loss locations
silencer aerodynamics

Silencer cutplane visualization showing velocity. Red is high speed, blue is low or zero velocity.

On the picture above you see an example from my previous work. With the simulations I could estimate the backpressure the silencer has on the positive displacement blower, and it was below the target, so I gave a green light to prototyping.

Silencer Aeroacoustics

Acoustics (airflow, vibration, resonances etc.) and aeroacoustics (only flow induced noise) are integral parts of a silencer, as the main purpose is to decrease the noise to a more human-comfortable level. As of today there is no hand-calculation or excel sheet available, that could predict the sound pressure level (SPL) of a silencer purely based on its dimensions. However, modern CFD technology can do that.

Acoustic transfer function cfd simulation damping

Acoustic damping of the silencer, simulated with CFD

The picture above shows the acoustic damping of the silencer from the inlet through the center to the outlet. It is clear that the device must damp all the frequencies, however in this example I tuned the muffler to damp 1000 Hz to an acceptable level. The silencer simulation project was successful, both the prescribed back-pressure and dB noise levels were satisfied.

Silencer Simulation Services

I am offering CFD simulation services and consulting for both the aerodynamic and the aeroacoustic design and improvement of silencers and mufflers.

  • exhaust system
  • exhaust silencer
  • chambered muffler
  • performance mufflers

Contact me to request more information and free quotation!

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