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

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.

2021 ◽  
Author(s):  
Massimo Masi ◽  
Piero Danieli ◽  
Andrea Lazzaretto

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.


Author(s):  
Leesang Cho ◽  
Hyunmin Choi ◽  
Seawook Lee ◽  
Jinsoo Cho

A study was done on the numerical and experimental analyses for the aerodynamic design of high performance of the counter rotating axial fan (CRF). Front rotor and rear rotor blades of a counter rotating axial fan are designed using the simplified meridional flow analysis method with the radial equilibrium equation and the free vortex design condition, according to design requirements. The through-flow fields and the aerodynamic characteristics of the designed rotor blades are analyzed by the matrix method and the frequency domain panel method. Fan performance curves are measured by following the standard fan testing method, KS B 6311. Three-dimensional flow fields in the CRF are analyzed by using the prism type five-hole probe. Performance characteristics of a counter-rotating axial flow fan are estimated for the variation of design parameters such as the hub to tip ratio, the taper ratio and the solidity. The effect of the hub to tip ratio on the fan efficiency is significant compared with the effects of other design parameters such as the solidity and the taper ratio. The fan efficiency is peak at the hub to tip ratio of 0.4, which is almost same point for the front rotor efficiency and rear rotor efficiency. The magnitudes of the meridional and relative velocities on the front and rear rotors are increased with the radial direction from hub to tip. This results in the reverse pressure gradient at the blade leading edges of both the front rotor and the rear rotor. Axial velocities of the CRF, which are measured by the prism type five-hole probe, are gradually increased at the mean radius due to the flow contraction effect. At the hub region, axial velocity is gradually decreased due to the flow separation and the hub vortex compare with design results. This result induces the increment of the incidence angle and the diffusion factor of the front rotor and the rear rotor.


2001 ◽  
Vol 124 (1) ◽  
pp. 280-283 ◽  
Author(s):  
Sandra Velarde-Sua´rez ◽  
Rafael Ballesteros-Tajadura ◽  
Carlos Santolaria-Morros ◽  
Eduardo Blanco-Marigorta

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.


Author(s):  
Zhihui Li ◽  
Juan Du ◽  
Qianfeng Zhang ◽  
Guofeng Ji ◽  
Hongwu Zhang

Boundary-layer-ingesting fans and compressors in the next-generation turbofan engines require high-performance operations under distorted inflow. The aim of this work is to study the effects of inlet distortions including inlet stagnation pressure and temperature distortion, on the aerodynamic performance of a transonic axial fan. Firstly, the validated full-annulus, unsteady, three-dimensional computational fluid dynamic code in conjunction with detached Eddy simulation approach is used here to simulate the fan flows assembly with individual inlet stagnation pressure/temperature distortion. Then, the propagation process of the inlet distortion waves is analyzed to understand how the aerodynamic performance degradation is triggered. The simulation results show that the fan performance is remarkably degraded when the inlet distortion is introduced. The leading-edge spillage, the trailing edge back flow and the “tornado vortex” occur when parts of fan blades encounter the incoming distorted flows. Finally, the responses of fan to the combined inlet stagnation distortion effects are discussed in this paper. It is found that the combined distortion effects can be predicted based on the sum of the performance responses to the individual constituent distortions. Furthermore, the relative location of the constituent distortions shows a non-ignorable influence on the overall fan performance, especially for the intensified inlet distortion.


2014 ◽  
Vol 598 ◽  
pp. 129-134
Author(s):  
Sheam Chyun Lin ◽  
Fu Yin Wang ◽  
Cheng Ju Chang ◽  
Hung Cheng Yen ◽  
Yung Jen Cheng

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.


Author(s):  
S-C Lin ◽  
M-L Tsai

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.


Author(s):  
Michael B. Wilkinson ◽  
Sybrand J. van der Spuy ◽  
Theodor W. von Backström

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.


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