High efficiency air blowers to meet future portable aerosol sampling applications were
designed, fabricated, and evaluated. A Centrifugal blower was designed to achieve a flow
rate of 100 L/min (1.67 x 10^-3 m^3/s) and a pressure rise of WC " 4 (1000 PA). Commercial
computational fluid dynamics (CFD) software, FLUENT 6.1.22, was used extensively
throughout the entire design cycle. The machine, Reynolds number (Re) , was around 10^5
suggesting a turbulent flow field. Renormalization Group (RNG) úâÂÂõ turbulent model
was used for FLUENT simulations. An existing design was scaled down to meet the
design needs. Characteristic curves showing static pressure rise as a function of flow rate
through the impeller were generated using FLUENT and these were validated through
experiments.
Experimentally measured efficiency (÷EXP) for the base-design was around 10%. This
was attributed to the low efficiency of the D.C. motor used. CFD simulations, using the
úâÂÂõ turbulent model and standard wall function approach, over-predicted the pressure
rise values and the percentage error was large.
Enhanced wall function under-predicted the pressure rise but gave better agreement (less
than 6% error) with experimental results. CFD predicted a blower scaled 70% in planar
direction (XZ) and 28% in axial direction (Y) and running at 19200 rpm
(70xz_28y@19.2k) as the most appropriate choice. The pressure rise is 1021 Pa at the design flow rate of 100 L/min. FLUENT predicts an efficiency value based on static head
(÷FLU) as 53.3%. Efficiency value based on measured static pressure rise value and the
electrical energy input to the motor (÷EXP) is 27.4%. This is almost a 2X improvement
over the value that one gets with the hand held vacuum system blower.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/5002 |
| Date | 25 April 2007 |
| Creators | Chadha, Raman |
| Contributors | Morrison, Gerald L. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 7648621 bytes, electronic, application/pdf, born digital |
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