IJSER Home >> Journal >> IJSER
International Journal of Scientific and Engineering Research
ISSN Online 2229-5518
ISSN Print: 2229-5518 9    
Website: http://www.ijser.org
scirp IJSER >> Volume 2, Issue 9, September 2011
Design of cooling fan for noise reduction using cfd
Full Text(PDF, 3000)  PP.  
G.V.R. seshagiri rao, Dr.V.V.subba rao
Aerofoil, acoustics, anechoic chamber, BPF, CFD, fluent, fan gambit, noise, NACA.
Cooling fans are one of the main noise sources in pumps. Tonal noise produced at a multiple of the rotational frequency of the fan, the so-called blade passing frequency (BPF) and its higher harmonics generally dominate fan noise. Noise reduction is perhaps one of the most important parameter in pumps. Every noise reduction process starts with identification of noise sources and ranking of sound sources from the machinery. After the initial identification of typical noise sources, the noise levels are to be eliminated or reduced either by modifying noise producing equipment or redesigning. In the present work, a cooling fan system of a sea water pump is considered. CATIA software is used to model the system and computational fluid dynamics (CFD) techniques are implemented for the analysis. In the first phase, CFD analysis procedure is developed and implemented to the baseline fan to designate the sound levels at inlet and outlet. Experiments are conducted for the same baseline fan in anechoic chamber and noticed high frequencies. The numerical results obtained through CFD are corroborated with experimental results and they are found to be in good agreement. After validating the theoretical procedure, an attempt is made to redesign the existing fan with National Advisory Committee for Aeronautics (NACA) series by way of changing geometrical parameters to reduce noise levels. The noise levels are computed and compared with the baseline fan results. The redesign fan results indicate that the noise levels are low by 5-10dBs.
[1] Gutin, L. On the sound field of a rotating propeller. Zhurnal tekhnicheskoifiziki, 1936, Translated as NACA TM 1195 (1948), 6, pp. 899-909.

[2] Lighthill, M. J. On sound generated aerodynamically: I. General theory. Proceedings of the Royal Society (London), 1952, A 211, pp. 564-587.

[3] Curle, N. The influence of solid boundaries upon aerodynamic sound. Proceedings of the Royal Society (London), 1955, A 231, pp. 505-514.

[4] Hubbard, H. H and Maglieri, D. J. Noise characteristics of helicopter rotors at tip speeds up to 900 feet per second. The Journal of the Acoustical Society of America, 1960, 32, pp. 1105-1107.

[5] Bragg, S. L. and Bridge, R. Noise from turbojet compressors. Journal of the Royal Aeronautical Society, 1964, 68, pp. l-10

[6] Sharland, I. J. Sources of noise in axial flow fans. Journal of Sound and Vibration, 1964, 1 (3), pp. 302-322.

[7] Powell, A. Origin and Characteristics of Sound Generation in Compressors and Fans. The Journal of the Acoustical Society of America, 1966, 40(5), pp. 1237.

[8] Ffowcs Williams, J. and Hawkings, D. Sound generation by turbulence and surfaces in arbitrary motion. Philosophical Transactions for the Royal Society of London, 1969, A 264, pp. 321–342.

[9] Duncan, P. E. and Dawson, B. Reduction of interaction tones from axial flow fans by suitable design of rotor configuration. Journal of Sound and Vibration, 1974, 33(2), pp. 143-1549.

[10] Boltezar, M., Mesaric, M. and Kuhelj, A. The influence of uneven blade spacing on the SPL and noise spectra radiated from radial fans. Journal of Sound and Vibration, 1988, 216(4), pp. 697-711.

[11] Quinlan, D. A. and Bent, P. H. High frequency noise generation in small axial flow fans. Journal of Sound and Vibration, 1988, 218(2), pp.225-232. Cudina, M. Noise generated by a vane-axial fan with inlet guide vanes. Noise control

[12] engineering journal, 1992, 39 (1), pp. 21-30.

[13] Neise, W. Review of fan noise generation mechanisms and control methods. An International INCE Symposium, 1992, Senlis, France, pp. 45–56.

[14] Maaloum, A., Kouidri, S. and Rey, R. Aeroacoustic performance evaluation of axial flow fans based on the unsteady pressure field on the blade surface. Applied Acoustics, 65 (2004), pp. 367–384.

[15] Kudo, T. Development of Noise-reduction method for radiator fan of automobile. Japan Society of Mechanical Engineers of Annual meeting Lecture collected papers in 2004(7), 2004, pp. 75-76.

Untitled Page