Forward-curved multi-blade centrifugal fans are widely used in central air conditioning systems. In this study
a new elliptical inlet nozzle in a multi-blade fan was designed
and experiments were conducted to investigate the effects of this structure on the fan performance. The results show that properly enlarging outlet area of the inlet nozzle will increase the aerodynamic performance of the fan but lead to greater A-weighted sound pressure level(SPL). Compared with the conventional inlet nozzle
the elliptical inlet nozzle with reasonable parameters and installation position can improve the aerodynamic performance. When the eccentricity angle θ was 0°and the eccentricity ratio
ε
1
or ε
2
was 0.067
the fan volume flow rate and the tot
al efficiency increase by 8.8%-12.8% and 1.7%-4.6%
respectively
while the A-weighted SPL decrease by 0.4-0.6 dB. Moreover
the fan volume flow rate and the total efficiency increase by 2.5%-6.0% and 0.6%-1.4%
respectively
while the A-weighted SPL decreases by 1.2-1.5 dB when θ was 30°and ε
1
or ε
2
was 0.067. This experimental study may provide an approach for improving the multi-blade fan performance.
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references
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