Lörcher, Frieder ; Hub, Sandra ; Sanjosé, Marlène ; Moreau, Stéphane (2022)
Investigations Concerning the Flow Stabilization of Backward Curved Centrifugal Impellers at Low Flow Rate.
FAN 2022 – International Conference on Fan Noise, Aerodynamics, Applications and Systems. Senlis, Frankreich (27.06.-29.06.2022)
doi: 10.26083/tuprints-00021682
Conference or Workshop Item, Primary publication, Publisher's Version
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Item Type: | Conference or Workshop Item |
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Type of entry: | Primary publication |
Title: | Investigations Concerning the Flow Stabilization of Backward Curved Centrifugal Impellers at Low Flow Rate |
Language: | English |
Date: | 2022 |
Place of Publication: | Darmstadt |
Collation: | 10 Seiten |
Event Title: | FAN 2022 – International Conference on Fan Noise, Aerodynamics, Applications and Systems |
Event Location: | Senlis, Frankreich |
Event Dates: | 27.06.-29.06.2022 |
DOI: | 10.26083/tuprints-00021682 |
Abstract: | At part load (at lower flow rate than the design flow rate), the flow pattern of backward curved, housingless centrifugal fans gets more and more unstable (unsteady) with sinking flow rate. In direct consequence, both a significant increase in noise emission, appearing especially as distinct subharmonic humps in the sound power spectra, and a decrease of the fan efficiency can be observed. By means of unsteady CFD simulations, which are validated by experimental results, the mechanisms for this undesired behavior have been investigated. It turns out that the phenomenon is self-induced by the impeller and does neither correlate to any upstream turbulence or flow inhomogenouities, nor any influence of the flow in the leakage gap can be identified. Instead, it seems to be induced by flow structures located on the downstream side of the impeller, where strong vortical structures, rotating in circumferential direction at a rotation speed with slip to the impeller, can be observed. These vortical structures are fed by detaching vorticity of highly loaded impeller blades, and they grow and change their structure with sinking flow rate. It was found out, that by controlling and partly avoiding these pressure-side rotating flow inhomogenouities, the part load behavior of the fan can be significantly improved at low flow rates. The result is that the impeller efficiency and the pressure rise can be enhanced at the corresponding duty points, whereas the noise generation can be strongly reduced. Thus, the operating range of the fan can be significantly extended towards lower flow rates. The numerical results are confirmed by some experimental results. |
Status: | Publisher's Version |
URN: | urn:nbn:de:tuda-tuprints-216829 |
Classification DDC: | 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering |
Divisions: | 16 Department of Mechanical Engineering |
Date Deposited: | 01 Aug 2022 11:41 |
Last Modified: | 05 Jun 2023 12:45 |
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/21682 |
PPN: | 497996537 |
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