scholarly journals Simulation on Aerodynamic Performance of a Variable-pitch Axial Flow Fan with Chordwise Swept Blades

2019 ◽  
Vol 55 (14) ◽  
pp. 151
Author(s):  
LI Chunxi ◽  
FAN Fuwei ◽  
LIU Hongkai ◽  
YE Xuemin
Keyword(s):  
Axial Flow ◽  
Aerodynamic Performance ◽  
Axial Flow Fan ◽  
Variable Pitch

Total Unsteadiness Downstream of an Axial Flow Fan With Variable Pitch Blades

2001 ◽  
Vol 124 (1) ◽  
pp. 280-283 ◽  
Author(s):  
Sandra Velarde-Sua´rez ◽  
Rafael Ballesteros-Tajadura ◽  
Carlos Santolaria-Morros ◽  
Eduardo Blanco-Marigorta
Keyword(s):  
Axial Flow ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Major Influence ◽  
Axial Flow Fan ◽  
Variable Pitch ◽  
Fan Performance ◽  
Performance Curves ◽  
Unsteady Operation ◽  
Variable Operating Conditions

Variable pitch axial flow fans are widely used in industrial applications to satisfy variable operating conditions. The change of the blade pitch leads to a different rotor geometry and has a major influence on the unsteady operation of the machine. In this work, an experimental research on an axial flow fan with variable pitch blades has been carried out. First of all, the fan performance curves has been obtained. Then the flow field has been measured at ten radial locations both at the inlet and exit rotor plane using hot wire anemometry. Velocity components and total unsteadiness were determined and analyzed in order to characterize the influence of pitch blade and operating conditions on the flow structure.

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.

OVERVIEW OF THE BEST 2020 AXIAL-FLOW FAN DATA AND INCLUSION IN SIMILARITY CHARTS FOR THE SEARCH OF THE BEST DESIGN

2022 ◽  
pp. 1-19
Author(s):  
Massimo Masi ◽  
Piero Danieli ◽  
Andrea Lazzaretto
Keyword(s):  
Axial Flow ◽  
Aerodynamic Performance ◽  
Design Parameters ◽  
Axial Fan ◽  
Axial Flow Fan ◽  
General Picture ◽  
Fan Performance ◽  
Global Performance ◽  
Present Design ◽  
Statistical Survey

Abstract The paper deals with the aerodynamic performance of ducted axial-flow fans available in the 2020 market and aims to create a general picture of the best designs and design trends, as a tool for fan designers. To this end, the paper first presents the general formulation of the similarity approach to the fan performance analysis, including the effects of rotational speed (which affects the validity of the Reynolds similarity) and turbomachine size (which can hinder the perfect geometrical similarity of some shape details). The second part reports a statistical survey of the axial-flow fan performance based on data from catalogues of major manufacturers, and compares the resulting Cordier-lines with optimum fan designs from empirical or CFD-based models available in the literature. In addition to the global performance at maximum aeraulic and total-to-static efficiencies, this survey uses the form of dimensionless Balje-Cordier charts to identify the trends and values of other design parameters, such as hub-to-tip ratio, blade count, and blade positioning angle. As a result, a summary of the aerodynamic performance of year 2020 best designs, the improvements achieved during the last forty years, and the present design trends in contra-rotating, vane-axial, and tube-axial fan types are made available to fan designers.

Spike and Modal Stall Inception Patterns in a Variable-pitch Axial-flow Fan

2003 ◽  
Vol 2003.2 (0) ◽  
pp. 27-28
Author(s):  
Takahiro NISHIOKA ◽  
Shuuji KURODA ◽  
Tadashi KOZU
Keyword(s):  
Axial Flow ◽  
Axial Flow Fan ◽  
Variable Pitch ◽  
Stall Inception

The Effects of Blade Loading Distribution and Blade Stacking on Aerodynamic Performance of a Semi-Open Type Axial Flow Fan

2016 ◽  
Vol 2016 (0) ◽  
pp. J0520305
Author(s):  
Yu KUWANO ◽  
Masato FURUKAWA ◽  
Kazutoyo YAMADA ◽  
Satoshi GUNJISHIMA ◽  
Naohiko HONMA ◽  
...  
Keyword(s):  
Axial Flow ◽  
Aerodynamic Performance ◽  
Axial Flow Fan ◽  
Blade Loading ◽  
Open Type

Investigation on Anti-Stall Ring Aerodynamic Performance in an Axial Flow Fan

2014 ◽  
Author(s):  
Alessandro Corsini ◽  
Giovanni Delibra ◽  
Franco Rispoli ◽  
Anthony G. Sheard ◽  
David Volponi
Keyword(s):  
Axial Flow ◽  
Aerodynamic Performance ◽  
Axial Flow Fan

scholarly journals Hot Wire Measurements During Rotating Stall in a Variable Pitch Axial Flow Fan

1996 ◽  
Author(s):  
Eduardo Blanco-Marigorta ◽  
Rafael Ballesteros-Tajadura ◽  
Carlos Santolaria
Keyword(s):  
Direct Method ◽  
Axial Flow ◽  
Rotating Stall ◽  
Hot Wire ◽  
Axial Flow Fan ◽  
Variable Pitch ◽  
Absolute Flow ◽  
Series Of Experiments ◽  
The Absolute ◽  
Absolute Frame

This work deals with a series of experiments on the influence of the blade pitch on the rotating stall phenomenon in an industrial variable pitch, low-speed axial flow fan with low hub-to-tip ratio. Two simple hot wires were used to detect the rotating stall. One in the absolute frame and the other in the relative frame rotating with the rotor. The rotating stall features were determined, ranging from the non-existence in the whole flow range with the lowest pitch tested to one and two flow cells with the greatest pitch. Then, a triple hot wire, calibrated by a direct method, was used to measure the absolute flow field upstream and downstream from the rotor, before and during rotating stall for five distinct blade pitches. These measurements allow us to characterize different rotating stall structures. To understand the phenomena better, some tests were carried out in the relative frame, with the probe rotating with the rotor. An intermediate blade pitch with a single rotating cell was selected and measurements were taken at three radial positions. Velocity maps for all these measurements are presented.

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