TITLE:
Performance and Internal Flow of Contra-Rotating Small-Sized Cooling Fan
AUTHORS:
Toru Shigemitsu, Keisuke Miyazaki, Katsuhiko Hirosawa, Hiroaki Fukuda
KEYWORDS:
Cooling Fan, Small-Sized Axial Fan, Contra-Rotating Rotors, Performance, Internal Flow
JOURNAL NAME:
Open Journal of Fluid Dynamics,
Vol.8 No.2,
June
29,
2018
ABSTRACT: High pressure and large flow rate small-sized cooling fans are used for servers
in data centers and there is a strong demand to increase its performance because
of increase of quantity of heat from servers. Contra-rotating rotors have
been adopted for some of high pressure and large flow rate cooling fans to
meet the demand. The performance curve of the contra-rotating small-sized
cooling fan with 40 mm square casing was investigated by an experimental
apparatus and its internal flow condition was clarified by the numerical analysis.
The fan static pressure of the front rotor was extremely low and it increased
significantly at the rear rotor. The uniform flow was achieved at the
inlet of the rear rotor because of the special shape of the casing between the
front and rear rotors. On the other hand, the tip leakage flow was large
enough to influence on the main flow of the test cooling fan by the design
specification of high pressure with compact rotor diameter.