Exa’s FIND module in PowerACOUSTICS determines noise source in an HVAC simulation. Image courtesy of Exa Corporation.
This module is able to determine the locations where airflow-induced noise, vibration and harshness (NVH) originate. Exa noted that a challenge with NVH optimizations is sifting through data representing the turbulent flow that causes the vibrations.
The FIND module is able to assess this fluid flow, determine points in the design that cause the noise, and rank them based on their contributions. The initial data used by FIND is created using Exa’s PowerFLOW solver. This solver digitally replicates the turbulent and transient flow of the fluid.
Additionally, PowerACOUSTICS can then create 3D visualizations of the simulations and even virtually create the noise the designs will make.
These capabilities allow engineers to address NVH issues early in the design cycle, before any prototyping begins, and assess the changes to their designs.
"Exa PowerFLOW accurately predicts aeroacoustic noise levels and PowerACOUSTICS FIND provides an unprecedented insight to identify noise sources. This allows engineers to make design changes that will reduce the generated noise levels," said Franck Pérot, senior director of acoustic applications for Exa.
"This capability applies to all aeroacoustics applications across multiple industries, such as wind noise and HVAC systems noise in automotive, landing-gear noise in aerospace, or applications in the rail industry,” added Pérot. “FIND provides significant additional value to our clients through these breakthrough capabilities that were not available anywhere, until now."
Car company BMW, is a partner of Exa. They are using the new FIND module to help optimize the HVAC systems in their cars.
BMW engineers noted that, without assessing the acoustics of an entire HVAC system, engineers can be led astray to the source of the noise. By assessing the noise created by each part separately, engineers might misjudge the biggest contributors to the overall HVAC noise. This is because even small noises can propagate through the HVAC system. This propagation will not be taken into consideration when assessing each part separately. Based on this information, engineering teams might focus their energy in the wrong places.
"We initially used PowerFLOW and PowerACOUSTICS FIND for the BMW 7 Series and Rolls-Royce Phantom," said BMW 's Group Leader for Overall Vehicle Development, Michael Spickenreuther. "We were so impressed with the noise-sourcing capability that we have now implemented FIND across all our platforms. FIND is enabling us to deliver quieter cars."
What challenges have you faced in an NVH simulation? Does FIND sound like something your organization could use? Comment below.