Numerical analysis of an axial flow fan with air-separator equipment

1995 ◽  
Author(s):  
S Aubert ◽  
W Dawes
Keyword(s):  
Numerical Analysis ◽  
Axial Flow ◽  
Axial Flow Fan ◽  
Air Separator

Improvement of Stalling Characteristics of an Axial-Flow Fan by Radial-Vaned Air-Separators

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Nobuyuki Yamaguchi ◽  
Masayuki Ogata ◽  
Yohei Kato
Keyword(s):  
Solid Wall ◽  
Axial Flow ◽  
Internal Flow ◽  
Rotor Blades ◽  
Relative Location ◽  
Flow Conditions ◽  
Axial Flow Fan ◽  
Light Load ◽  
Stall Prevention ◽  
Air Separator

An improved construction of air-separator device, which has radial-vanes embedded within its inlet circumferential opening with their leading-edges facing the moving tips of the fan rotor-blades so as to scoop the tip flow, was investigated with respect to the stall-prevention effect on a low-speed, single-stage, lightly loaded, axial-flow fan. Stall-prevention effects by the separator layout, relative location of the separator to the rotor-blades, and widths of the openings of the air-separator inlet and exit were parametrically surveyed. As far as the particular fan is concerned, the device together with the best relative location has proved to be able to eliminate effectively the stall zone having existed in the original solid-wall characteristics, which has confirmed the promising potential of the device. Guidelines were obtained from the data for optimizing relative locations of the device to the rotor-blades, maximizing the stall-prevention effect of the device, and minimizing the axial size of the device for a required stall-prevention effect, at least for the particular fan and possibly for fans of similar light-load fans. The data suggest the changing internal flow conditions affected by the device conditions.

scholarly journals A Study on the Flow within the Flow Passage of an Axial Flow Fan Equipped with Air-separator

1986 ◽  
Vol 29 (256) ◽  
pp. 3394-3401
Author(s):  
Yutaka MIYAKE ◽  
Takehiko INABA ◽  
Yoshikiyo NISHIKAWA ◽  
Ikutaro NOJI ◽  
Tetsuaki KATO
Keyword(s):  
Axial Flow ◽  
Axial Flow Fan ◽  
Flow Passage ◽  
Air Separator

scholarly journals Noise from an Axial-flow Fan with an Air Separator.

1998 ◽  
Vol 64 (617) ◽  
pp. 148-154
Author(s):  
Takahiro NISHIOKA ◽  
Tadashi KOOZU ◽  
Kouji NAKAGAWA
Keyword(s):  
Axial Flow ◽  
Axial Flow Fan ◽  
Air Separator

Improving Stall Margin by Using an Air-Separator for a Variable-Pitch Axial-Flow Fan

2004 ◽  
Author(s):  
Takahiro Nishioka ◽  
Shuuji Kuroda ◽  
Tadashi Kozu
Keyword(s):  
Axial Flow ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Axial Flow Fan ◽  
Clearance Ratio ◽  
Variable Pitch ◽  
Stall Margin ◽  
Operating Range ◽  
Exposure Ratio ◽  
Air Separator

An air-separator for extending the operating range of a variable-pitch axial-flow fan has been developed. It has a circular-are outer casing, a part of which forms the guide vane at the inlet of the air-separator. To obtain a wide operating range and to minimize penalties in terms of efficiency and noise, the influence of exposure and clearance ratios at various stagger-angle settings for rotor blades in low-speed and high-speed axial flow fans was experimentally investigated. Flow distributions and pressure fluctuations downstream of the rotor were also measured in order to investigate the influence of the air-separator on rotating stall. The distributions and fluctuations suggested that the air-separator decreased the blockage effect near the rotor tip and suppressed the rotating stall. Moreover, stall-margin and pressure-rise improvements were independent of the clearance ratio. These improvements depended on the exposure ratio and stagger-angle settings for the rotor blades. The fan efficiency for the air-separator also depended on the exposure ratio. In addition, the efficiency had the opposite tendency to the stall-margin and pressure-rise improvements. In contrast, the noise for the air-separator was independent of the exposure ratio and decreased as the clearance ratio increased. For the optimum combination of the exposure and clearance ratios, the stall-margin and pressure-rise were improved by over 20% with minimized penalties in terms of efficiency and noise. It is concluded from these results that the developed air-separator can provide a wide operating range for a variable-pitch axial-flow fan.

Improvement of Unstable Characteristics of an Axial Flow Fan by Air-Separator Equipment

1987 ◽  
Vol 109 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Y. Miyake ◽  
T. Inaba ◽  
T. Kato
Keyword(s):  
Pressure Distribution ◽  
Axial Flow ◽  
Rotating Stall ◽  
Axial Flow Fan ◽  
Blade Passage ◽  
Geometric Conditions ◽  
Different Types ◽  
Blade Tip ◽  
Discharge Distribution ◽  
Air Separator

The authors’ previous papers demonstrated that an air-separator is the most effective equipment among various different types for the improvement of unstable characteristics of an axial-flow rotor. Further experiments revealed that this equipment could eliminate the unstable characteristics thoroughly even for a build which originally accompanied a heavy rotating stall. This paper describes the geometric conditions to realize this and discusses its performance mechanism on the basis of the experiments showing the discharge distribution of the bleeding flow from the blade tip to separator passage as well as the pressure distribution in a blade passage at the tip section of the rotor. It is suggested that the equipment is equally useful at any stage of a multistage rotor.

Suppression of Rotating Stall by an Air-separator in an Axial-flow Fan

2004 ◽  
Vol 2004 (0) ◽  
pp. 14 ◽  
Author(s):  
Takuhiro NISHIOKA ◽  
Shuuji KURODA ◽  
Tsukasa NAGANO
Keyword(s):  
Axial Flow ◽  
Rotating Stall ◽  
Axial Flow Fan ◽  
Air Separator
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