An integrated performance analysis for a small axial-flow fan

2010 ◽  
Vol 224 (9) ◽  
pp. 1981-1994 ◽  
Author(s):  
S-C Lin ◽  
M-L Tsai
Keyword(s):  
High Performance ◽  
Noise Analysis ◽  
Technical Information ◽  
Axial Flow ◽  
Operating Conditions ◽  
Numerical Control ◽  
Field Analysis ◽  
Axial Flow Fan ◽  
Fan Performance ◽  
Efficiency Estimation

Owing to the high system resistance and space limitations on computer devices, many researchers have begun to pay more attention to developing high-performance axial-flow fans. Evidently, evaluating the fan performance under different operating conditions is essential for both designer and practical engineering applications. However, previous studies do not provide a detailed flow-field analysis, torque prediction, efficiency estimation at various operating points, and qualitative numerical prediction of sound generation. Thus, this comprehensive study was performed with the aim to offer the aforementioned technical information and completely evaluate the fan performance. In this study, computational fluid dynamics (CFD) simulations and experimental measurements are utilized to perform flow visualization, torque calculation, efficiency estimation, and noise analysis. For demonstration purposes, a 120 mm-diameter axial-flow fan is designed and fabricated via computer numerical control (CNC) to serve as the research subject. The result indicates that the P— Q curve and the sound pressure level (SPL) spectrum of the experiment are in agreement with those of numerical simulations. The numerical deviations in maximum volumetric flowrate and static pressure are approximately 7 per cent and 13 per cent, respectively. Regarding the acoustic characteristics, the overall SPLs for measured spectra and large eddy simulation (LES) calculation are 51.3 dB and 48.1 dB, respectively. Consequently, this study establishes an integrated aerodynamic, acoustic, and electro-mechanical evaluation approach that can be used as an important tool for fan designers.

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.

Performance Improvement on Axial-Flow Fan by Imposing Proper Frame Ribs

2014 ◽  
Vol 598 ◽  
pp. 129-134
Author(s):  
Sheam Chyun Lin ◽  
Fu Yin Wang ◽  
Cheng Ju Chang ◽  
Hung Cheng Yen ◽  
Yung Jen Cheng
Keyword(s):  
Performance Improvement ◽  
Rotor Blade ◽  
High Performance ◽  
Axial Flow ◽  
Tip Clearance ◽  
Geometrical Parameters ◽  
Axial Flow Fan ◽  
Design Guideline ◽  
Fan Performance ◽  
Air Passage

Generally, most research attempts on the axial-flow fan focus on optimizing rotor blade and tip clearance to enhance its aerodynamic and acoustic performances. Few efforts aim at finding out the appropriate frame rib, which is a supporting and vital part within the air passage and thus has significant influence on the turbulent flow near the blade trailing edge. Therefore, this study intends to investigate the geometrical parameters of the frame rib systematically by using an integrated scheme, which consists of numerical simulation, mockup fabrication, and experimental verification. At first, a high-performance fan (90×90×38 mm3) is constructed to serve as the sample fan for this investigation. Then three geometrical sections (triangle, cylinder, and arc) of frame rib are examined systematically to provide a design guideline on utilizing the appropriate frame rib for enhancing the fan performance.

scholarly journals Effects of Operating Conditions on the Flow in the Moving Blade Passage of a Single Stage Axial-Flow Fan

1997 ◽  
Vol 3 (4) ◽  
pp. 269-276 ◽  
Author(s):  
Tsutomu Adachi ◽  
Yutaka Yamashita ◽  
Kennichiro Yasuhara ◽  
Tatsuo Kawai
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Hot Wire ◽  
Axial Flow Fan ◽  
Blade Passage ◽  
Operational Conditions ◽  
Flow Phenomena ◽  
Steady Velocity

Three dimensional steady and unsteady velocity distributions in the axial flow fan were measured using a hot wire probe for various operational conditions, various rotational speeds and various measuring positions. For measuring the velocity distributions in the blade passage, a specially designed and manufactured hot wire traversing apparatus was used. Steady velocity distributions, turning angles, effects of incident to the cascade, flow leakage through the tip clearance and effects of the flow separation show the flow phenomena through the blade passages. Unsteady velocity distributions show time dependent procedures of the wake flowing through the moving blade passage. Considering these results of measurements, the effects of the upstream stationary blade and the effects of Reynolds number on the flow were considered.

scholarly journals Investigation of the Flow Field in the Vicinity of an Axial Flow Fan During Low Flow Rates

2014 ◽  
Author(s):  
Francois G. Louw ◽  
Theodor W. von Backström ◽  
Sybrand J. van der Spuy
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Flow Rate ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Flow ◽  
Low Flow ◽  
Axial Flow Fan ◽  
Free Vortex ◽  
Flow Rates

Large axial flow fans are used in forced draft air cooled heat exchangers (ACHEs). Previous studies have shown that adverse operating conditions cause certain sectors of the fan, or the fan as a whole to operate at very low flow rates, thereby reducing the cooling effectiveness of the ACHE. The present study is directed towards the experimental and numerical analyses of the flow in the vicinity of an axial flow fan during low flow rates. This is done to obtain the global flow structure up and downstream of the fan. A near-free-vortex fan, designed for specific application in ACHEs, is used for the investigation. Experimental fan testing was conducted in a British Standard 848, type A fan test facility, to obtain the fan characteristic. Both steady-state and time-dependent numerical simulations were performed, depending on the operating condition of the fan, using the Realizable k-ε turbulence model. Good agreement is found between the numerically and experimentally obtained fan characteristic data. Using data from the numerical simulations, the time and circumferentially averaged flow field is presented. At the design flow rate the downstream fan jet mainly moves in the axial and tangential direction, as expected for a free-vortex design criteria, with a small amount of radial flow that can be observed. As the flow rate through the fan is decreased, it is evident that the down-stream fan jet gradually shifts more diagonally outwards, and the region where reverse flow occur between the fan jet and the fan rotational axis increases. At very low flow rates the flow close to the tip reverses through the fan, producing a small recirculation zone as well as swirl at certain locations upstream of the 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.

Performance Testing of an Axial Flow Fan Designed for Air-Cooled Heat Exchanger Applications

2018 ◽  
Vol 141 (5) ◽  
Author(s):  
Michael B. Wilkinson ◽  
Sybrand J. van der Spuy ◽  
Theodor W. von Backström
Keyword(s):  
Experimental Data ◽  
Static Pressure ◽  
Axial Flow ◽  
Pressure Rise ◽  
Test Facility ◽  
Cfd Model ◽  
Blade Angle ◽  
Axial Flow Fan ◽  
Fan Performance ◽  
Static Efficiency

An axial flow fan developed in the previous study is tested in order to characterize its performance. The M-fan, a 7.3152 m diameter rotor only axial flow fan was designed to perform well under the challenging operating conditions encountered in air-cooled heat exchangers. Preliminary computational fluid dynamics (CFD) results obtained using an actuator disk model (ADM) as well as a periodic three dimensional model indicate that the fan meets the specified performance targets, with an expected total-to-static efficiency of 59.4% and a total-to-static pressure rise of 114.7 Pa at the operating point. Experimental tests are performed on the M-fan in order to determine its performance across a full range of flow rates. A range of fan configurations are tested in order to ascertain the effect of tip clearance, blade angle, and hub configuration on fan performance. Due to the lack of a suitable facility for testing a large diameter fan, a scaled 1.542 m diameter model is tested on the ISO 5801 type A fan test facility at Stellenbosch University. A Reynolds-averaged Navier–Stokes CFD model representing the M-fan in the test facility is also developed in order to provide additional insight into the flow field in the vicinity of the fan blades. The results of the CFD model will be validated using the experimental data obtained. Both the CFD results and the experimental data obtained are compared to the initial CFD results for the full scale fan, as obtained in the previous study, by means of fan scaling laws. Experimental data indicate that the M-fan does not meet the pressure requirement set out in the initial study at the design blade setting angle of 34 deg. Under these conditions, the M-fan attains a total-to-static pressure rise of 102.5 Pa and a total-to-static efficiency of 56.4%, running with a tip gap of 2 mm. Increasing the blade angle is shown to be a potential remedy, improving the total-to-static pressure rise and efficiency obtained at the operating point. The M-fan is also shown to be highly sensitive to increasing tip gap, with larger tip gaps substantially reducing fan performance. The losses due to tip gap are also shown to be overestimated by the CFD simulations. Both experimental and numerically obtained results indicate lower fan total-to-static efficiencies than obtained in the initial CFD study. Results indicate that the M-fan is suited to its intended application, however, it should be operated with a smaller tip gap than initially recommended and a larger blade setting angle. Hub configuration is also shown to have an influence on fan performance, potentially improving performance at low flow rates.

Three-Dimensional Noise Analysis of an Axial-Flow Fan using Computational Aero-Acoustics

2012 ◽  
Vol 15 (5) ◽  
pp. 48-53
Author(s):  
Joo-Hyung Kim ◽  
Jin-Hyuk Kim ◽  
Seungyeol Shin ◽  
Kwang-Yong Kim ◽  
Seungbae Lee
Keyword(s):  
Noise Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Axial Flow Fan
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