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Noise and airflow simulation for engines, generators and equipment that moves air

If your product moves air or exhaust gas through a silencer, intake, duct, vent or enclosure, that flow path often sets both its noise and its pressure drop. Both are easiest to change during design, before prototypes and tooling, and that is the stage we simulate them. Based in Plymouth, Minnesota, we work with Twin Cities manufacturers and with engineering teams well beyond the metro.

01Industry group

Power Generation & Electrical Equipment

Engine-driven generator sets and electrical equipment that move air to breathe and cool, and still have to meet a sound target.

Generator Sets & Power Generation

Engine-driven generator sets pull large volumes of cooling and combustion air through sound-attenuated enclosures. The ventilation path has to pass that air with little restriction while keeping radiator-fan and engine noise inside.

Typical products: Standby and prime-power generator sets, sound-attenuated enclosures, and portable generators.

  • Exhaust silencer attenuation and back pressure

    The exhaust silencer must attenuate the firing frequency and its harmonics without exceeding the engine maker’s back-pressure limit. An acoustic model predicts its transmission loss; CFD predicts its back pressure.

    Related: Acoustic Modeling & Simulation · CFD Flow & Pressure Drop

  • Inlet and outlet ventilation paths

    Louvers, acoustic baffles and splitter silencers on the air inlet and discharge. Their length, spacing and lining decide how much fan and engine noise escapes.

    Related: Acoustic Modeling & Simulation · Noise Control & Mitigation

  • Ventilation airflow against attenuation

    Longer splitters with narrower airways attenuate more but add pressure drop, and the ventilation path must stay within the allowable cooling-air restriction. Modeling both finds the quietest layout that still cools at full load.

    Related: Aerodynamic Modeling & Simulation · Acoustic Modeling & Simulation

  • Exhaust outlet and rain-cap flow

    Piping, bends, the silencer and the rain cap all add to total back pressure. CFD shows where the losses are and how evenly the flow leaves the outlet.

    Related: CFD Flow & Pressure Drop

  • Enclosure noise against a site sound limit

    Data centers, hospitals and residential sites often set a sound limit at a distance or property line. Predicting the enclosure’s level early shows whether a design will qualify.

    Related: Acoustic Modeling & Simulation · Noise Control & Mitigation

Typical questions from engineering teams

  • The site needs a lower sound level than our standard enclosure gives. Do we need a new enclosure, or a better ventilation path?
  • If we add splitter silencers, will the radiator still get enough air at full load?

Services for this work: Acoustic Modeling · CFD Flow & Pressure Drop · Noise Control · Aerodynamic Modeling

Engine and generator noise simulation in depth

Electrical Equipment

Fan-cooled electrical equipment moves air through tight enclosures, past filters, heat sinks and louvers, and that cooling airflow is often the dominant noise source. The constraint is strict: a quieter design cannot run hotter.

Typical products: Drives, switchgear and control enclosures, power electronics, UPS systems, chargers, and IT and telecom cabinets.

Typical questions from engineering teams

  • We moved to a higher-power drive and the fans got louder. Can we keep the airflow and lose the noise?
  • Which louver and filter layout lets the least fan noise out of the cabinet?

Services for this work: Aerodynamic Modeling · Aeroacoustics Consulting · Noise Control · Acoustic Modeling

02Industry group

Machinery & Air-Moving Equipment

Machines and products where moving air is the job, or a large part of it.

Industrial Machinery Manufacturing

Industrial machines move air for cooling, combustion, conveying and ventilation, and that airflow is often one of the strongest noise sources on the machine. How the machine installs and packages its fans, ducts and openings decides much of what an operator hears.

Typical products: Machine tools and process machinery, packaging and converting lines, industrial dryers and ovens, pneumatic conveying, and machines with built-in cooling or extraction fans.

Typical questions from engineering teams

  • The fan is quiet on the bench, but the machine is loud. Is it the fan, or the way we installed it?
  • We have to hit a sound level on a new machine and the first prototype is months away. Will it pass?

Services for this work: Aerodynamic Modeling · Aeroacoustics Consulting · Acoustic Modeling · CFD Flow & Pressure Drop · Noise Control

Filtration, Intake & Exhaust Systems

Intakes, silencers and collectors have to pass air with little restriction while keeping the noise of fans, engines and discharges in check.

Typical products: Engine air intakes and air filters, intake and exhaust silencers, and dust and fume collectors.

  • Attenuation against pressure drop

    Silencer chambers, baffles and intake passages add attenuation and restriction together. Modeling both on the same geometry finds the layout with the best balance.

    Related: Acoustic Modeling & Simulation · CFD Flow & Pressure Drop

  • Engine intake and air-filter restriction

    Engine manufacturers set a maximum intake restriction. CFD of the intake, filter and silencer shows where the losses are before the system is built.

    Related: CFD Flow & Pressure Drop

  • Collector and discharge noise

    On dust and fume collectors the discharge can be the loudest point. Ranking the discharge, the fan and the casing shows whether a silencer, a discharge change or treatment will help most.

    Related: Noise Control & Mitigation · Acoustic Modeling & Simulation

Services for this work: Acoustic Modeling · CFD Flow & Pressure Drop · Noise Control

Engine and generator noise simulation in depth

Fans, Blowers & Air-Moving Equipment

For a fan or blower the airflow is the product, so its noise is set by blade, housing and cutoff geometry and by how it is installed. Sound data often ships with the product, across every size in the family.

Typical products: Axial and centrifugal fans, blowers, fan arrays and plenum fans, and ventilation fans.

Typical questions from engineering teams

  • Our new impeller has a tone the old one didn’t. What changed, and how do we get rid of it?
  • Our fan meets its rating on the test stand but falls short in the customer’s unit. Is the installation costing us pressure?

Services for this work: Aeroacoustics Consulting · Noise Control · Aerodynamic Modeling

03HVAC & Cooling

Commercial HVAC, Air Handling & Data-Center Cooling

In air handlers and cooling units, fans, coils and grilles generate noise that travels down the ductwork into occupied space or out to the property line. For data-center cooling equipment, community noise can be part of local permitting.

Typical products: Air handlers, rooftop units, fan walls and fan arrays, CRAH and CRAC units, condensing units, terminal units, grilles and diffusers.

  • Plenum and discharge noise

    Abrupt transitions, turning vanes and discharge plenums generate turbulence noise and can excite plenum resonances. Geometry changes are cheaper on screen than in sheet metal.

    Related: Acoustic Modeling & Simulation · Aerodynamic Modeling & Simulation

  • Grille, diffuser and louver noise

    Self-generated noise from grilles, diffusers and louvers rises steeply with face velocity. Airflow simulation shows where face velocity is high or uneven, so blade profile and spacing can be compared before test.

    Related: Aerodynamic Modeling & Simulation · Noise Control & Mitigation

  • Outdoor-unit noise at the property line

    Condensing units and rooftop equipment have to stay under limits at nearby property lines. Modeling how the unit’s sound reaches the property line lets a design aim at that limit, not only at its rating.

    Related: Acoustic Modeling & Simulation · Noise Control & Mitigation

  • Fan-array airflow

    Fan count, spacing and inlet arrangement change how evenly air reaches coils and filters and how hard each fan works. Layouts can be compared before the array is built.

    Related: Aerodynamic Modeling & Simulation

  • Data-center cooling equipment and community noise

    Noise from cooling units and heat-rejection fans can be raised during data-center permitting. Equipment that is quieter at the source gives site teams more room to meet local expectations.

    Related: Noise Control & Mitigation · Acoustic Modeling & Simulation

Typical questions from engineering teams

  • Our unit meets its sound rating, but sites keep asking for something quieter at the property line. Where do we start?
  • Our coil sees uneven airflow from the fan wall. Which fan layout evens it out?

Services for this work: Acoustic Modeling · Aerodynamic Modeling · Noise Control

Simulation study

What a simulation study needs

A typical study starts with geometry and an operating point and ends with a written answer to one engineering question.

What you send

  • CAD geometry of the product or flow path
  • The operating point: flow rate, speed, temperature and pressure
  • The design options to compare, or the levels to predict
  • Any measured data you already have

What comes back

  • Predicted attenuation, sound levels or pressure drop
  • The dominant noise paths or pressure losses
  • A comparison of the design options
  • A short written recommendation

Sensitive files

Please don’t send CAD through the website form. Files are exchanged after first contact.

Different product, same physics?

Silencer attenuation, duct and enclosure acoustics, and the trade-off against pressure drop turn up in many products that are not listed here. If it moves air or exhaust gas, describe the problem. The first conversation establishes whether simulation, and SH Consulting, is the right fit.

Discuss a Simulation

Discuss your simulation or aeroacoustics challenge

Describe the product, the noise or flow behavior, and the decision you need to make. The first conversation is a technical one.

Discuss a Simulation