TY - JOUR
T1 - Prediction of Blade-Passing Frequency Noise in a Low Specific Speed Centrifugal Blower
AU - Ohta, Yutaka
AU - Outa, Eisuke
AU - Tajima, Kiyohiro
PY - 1993
Y1 - 1993
N2 - The blade-passing frequency noise of a low specific speed centrifugal blower is discussed by separating the intensity of the noise source and the response of the transmission passage. The frequency-response function in the transmission passage has previously been evaluated by the authors using a plane wave model, and the results have indicated various effects of the blower speed, blade number and inlet duct length. In the present study, the effective location of the noise source is determined by analyzing the cross correlation between measured data of the blower suction noise and pressure fluctuations on the scroll surface. Then, the surface density distribution of a dipole source is determined from the pressure fluctuation which is expressed by the quasi-steady dynamic pressure of the traveling blade wake. By integration of the surface density spectrum of the noise source over the effective source area, the free-field noise level is obtained. The blower suction noise level is finally predicted by operating the frequency-response function. The results agree well with the measured data, and the effect of the distance between the impeller and the scroll cut off is accounted for satisfactorily.
AB - The blade-passing frequency noise of a low specific speed centrifugal blower is discussed by separating the intensity of the noise source and the response of the transmission passage. The frequency-response function in the transmission passage has previously been evaluated by the authors using a plane wave model, and the results have indicated various effects of the blower speed, blade number and inlet duct length. In the present study, the effective location of the noise source is determined by analyzing the cross correlation between measured data of the blower suction noise and pressure fluctuations on the scroll surface. Then, the surface density distribution of a dipole source is determined from the pressure fluctuation which is expressed by the quasi-steady dynamic pressure of the traveling blade wake. By integration of the surface density spectrum of the noise source over the effective source area, the free-field noise level is obtained. The blower suction noise level is finally predicted by operating the frequency-response function. The results agree well with the measured data, and the effect of the distance between the impeller and the scroll cut off is accounted for satisfactorily.
KW - Aerodynamic Acoustics
KW - Blade-Passing Frequency Noise
KW - Blower
KW - Correlation
KW - Flow Measurements
KW - Fluid Machinery
KW - Similarity Rule of Blower Noise
KW - Turbomachinery
KW - Wake
UR - http://www.scopus.com/inward/record.url?scp=85007684374&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85007684374&partnerID=8YFLogxK
U2 - 10.1299/kikaib.59.1618
DO - 10.1299/kikaib.59.1618
M3 - Article
AN - SCOPUS:85007684374
VL - 59
SP - 1618
EP - 1625
JO - Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
JF - Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
SN - 0387-5016
IS - 561
ER -