AERODYNAMIC NOISE OF BLADE GRILL HVAC SYSTEMS AT LOW MACH NUMBERS

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F17%3A00312866" target="_blank" >RIV/68407700:21220/17:00312866 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.iiav.org/archives_icsv_last/2017_icsv24/content/papers/papers/full_paper_1024_20170504093534330.pdf" target="_blank" >https://www.iiav.org/archives_icsv_last/2017_icsv24/content/papers/papers/full_paper_1024_20170504093534330.pdf</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

AERODYNAMIC NOISE OF BLADE GRILL HVAC SYSTEMS AT LOW MACH NUMBERS

Popis výsledku v původním jazyce

The paper deals with aerodynamic noise which is generated at low Mach and Reynolds numbers, by air flowing over a blade grill commonly used as a terminal diffuser of air-distribution systems. The aerodynamic noise of HVAC (Heating, Ventilating and Air Con-ditioning) systems is undesirable in residential buildings, office buildings, hospitals and especially in spaces with high acoustic demands such as TV or recording studios. It has been experimentally assessed for a blade grill and a cylinder, in order to find similarities between their acoustic spectra. The main challenge of the experiment was to build an ex-perimental test stand with a requirement of low noise from the fan. The goal of the paper was to compare acoustic spectra of the air flow around the cylinder, as the reference aero-dynamic source, and the blade grill, as the source which generates noise by vibrations of the blade surface and by turbulent flow. The final step was to measure the fluctuations by hot wire anemometry and compare the spectra of turbulent flow fluctuations and aerody-namic noise. The air flow around the cylinder generates a peak of acoustic spectrum with-in the Strouhal number range of 0.15 to 0.2, which is not dependent on the material of the cylinder. This result is commonly presented in publications and has been verified by pre-vious experiments. However, it has been found that the air flow around the blade grill generates many peaks in acoustic spectra, i.e. for the Strouhal number range of 0.15 to 0.25 and also higher values 0.5 and 0.7. The peaks in acoustic spectra of the blade grill are discrete tones. There are three peaks in acoustic spectra for low velocity of air flow (under 8 m/s), and only one peak for higher velocity, within the Strouhal number range of 0.15 to 0.25.

Název v anglickém jazyce

AERODYNAMIC NOISE OF BLADE GRILL HVAC SYSTEMS AT LOW MACH NUMBERS

Popis výsledku anglicky

The paper deals with aerodynamic noise which is generated at low Mach and Reynolds numbers, by air flowing over a blade grill commonly used as a terminal diffuser of air-distribution systems. The aerodynamic noise of HVAC (Heating, Ventilating and Air Con-ditioning) systems is undesirable in residential buildings, office buildings, hospitals and especially in spaces with high acoustic demands such as TV or recording studios. It has been experimentally assessed for a blade grill and a cylinder, in order to find similarities between their acoustic spectra. The main challenge of the experiment was to build an ex-perimental test stand with a requirement of low noise from the fan. The goal of the paper was to compare acoustic spectra of the air flow around the cylinder, as the reference aero-dynamic source, and the blade grill, as the source which generates noise by vibrations of the blade surface and by turbulent flow. The final step was to measure the fluctuations by hot wire anemometry and compare the spectra of turbulent flow fluctuations and aerody-namic noise. The air flow around the cylinder generates a peak of acoustic spectrum with-in the Strouhal number range of 0.15 to 0.2, which is not dependent on the material of the cylinder. This result is commonly presented in publications and has been verified by pre-vious experiments. However, it has been found that the air flow around the blade grill generates many peaks in acoustic spectra, i.e. for the Strouhal number range of 0.15 to 0.25 and also higher values 0.5 and 0.7. The peaks in acoustic spectra of the blade grill are discrete tones. There are three peaks in acoustic spectra for low velocity of air flow (under 8 m/s), and only one peak for higher velocity, within the Strouhal number range of 0.15 to 0.25.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

10307 - Acoustics

Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

the 24th International Congress on Sound and Vibration

ISBN

978-1-906913-27-4

ISSN

2329-3675

e-ISSN

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Počet stran výsledku

8

Strana od-do

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Název nakladatele

IIAV - International Institute of Acoustics and Vibration

Místo vydání

Auburn

Místo konání akce

London

Datum konání akce

23. 7. 2017

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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