Accession Number:

ADA231288

Title:

Acoustic Diagnostics of an Automotive HVAC System

Descriptive Note:

Technical rept.,

Corporate Author:

PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB

Report Date:

1991-01-01

Pagination or Media Count:

116.0

Abstract:

The heating, ventilation, and air conditioning HVAC system of an automobile can be a source of acoustic annoyance, particularly when it is operated under maximum airflow conditions. In order to suggest possible design changes for the purpose of noise control, a systematic characterization of the acoustic sources and mechanisms must be conducted initially. This report addresses such a characterization for a typical automotive system. The approach is based on acoustic intensity measurements of the stand-alone HVAC system operating under maximum airflow conditions in the ARL Penn State flow-through anechoic chamber. The experimental data indicate that the centrifugal blower is the dominant low-frequency source of noise, while separation zones and the flow over sharp edges within the HVAC system ducting are secondary sources of noise that become increasingly dominant as the frequency exceeds 3 kHz. Qualification of these identified sources of sound is aided by detailed flow visualizations of the subject system. Recommendations for acoustic improvements to the system are provided.

Subject Categories:

  • Air Conditioning, Heating, Lighting and Ventilating

Distribution Statement:

APPROVED FOR PUBLIC RELEASE