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Simulation of aerodynamic noise from centrifugal fan of HVAC in automobile |
Clean Energy Automotive Engineering Center, School of Automotive Studies, Tongji University, Shanghai 201804, China |
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Abstract Transforming the Lighthill equation into a variational form, the aerodynamic noise of centrifugal fan of HVAC in automobile was numerically calculated by finite element method with the consideration of the reflection and refraction of sound transmission in complex solid surfaces. Simplifying the free space Green function as a free space problem for far field sound radiation, the aerodynamic noise was also calculated by integration method. The unsteady flow inside centrifugal fan was calculated by DES model to show that the major noise sources were from blade pressure surfaces and the front and rear parts of tongue according to the analyses of the contours of vorticity, sound power and pressure fluctuation at different locations. Two aeroacoustic finite element models were established to calculate the radiating noise of centrifugal fan with and without consideration of volute. The comparison results show that the aeroacoustic calculation results based on finite element method have good consistency with reality, while the simplification of integral solution by Green function results in large error.
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Received: 16 April 2012
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