scholarly journals The performance improvement of axial flow fan with large tip clearance by using winglet

2018 ◽  
Vol 186 ◽  
pp. 012009
Author(s):  
Lee Chan ◽  
Hyun Gwon Kil ◽  
Hyo Sang Kim ◽  
Hwan Geol Yeo
Keyword(s):  
Performance Improvement ◽  
Axial Flow ◽  
Tip Clearance ◽  
Axial Flow Fan

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.

Measurement and analysis of tip clearance unsteady flow spectrum in axial-flow fan rotor

2008 ◽  
Vol 2 (4) ◽  
pp. 448-452 ◽  
Author(s):  
Bo Liu ◽  
Weimin Hou ◽  
Changyou Ma ◽  
Yangang Wang ◽  
Qiang Zhou
Keyword(s):  
Unsteady Flow ◽  
Axial Flow ◽  
Tip Clearance ◽  
Axial Flow Fan ◽  
Measurement And Analysis

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.

A Numerical Study on the Structure of Tip Clearance Flow in a Highly Forward-Swept Axial-Flow Fan

2002 ◽  
Author(s):  
Gong Hee Lee ◽  
Je Hyun Baek
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Axial Flow ◽  
Streamwise Velocity ◽  
Tip Clearance ◽  
Wake Flow ◽  
Axial Flow Fan ◽  
Step Method ◽  
Fractional Step Method ◽  
Tip Clearance Flow

A three-dimensional Navier-Stokes analysis was performed to investigate the tip clearance flows in a highly forward-swept axial flow fan operating at design condition. The numerical solution was based on a fractional step method, and two-layer k-ε model was used to obtain the eddy viscosity. The tip leakage vortex decayed very quickly inside the blade passage and, thus, no distinct leakage vortex appeared behind trailing edge. The main reason was the severe decrease of the streamwise velocity of the vortex. Also the interaction of the vortex with the casing boundary layer and the through-flow were other possibilities of the fast decay of the vortex. Comparison between the numerical results and LDV measurements data indicated that the complex viscous flow patterns inside the tip region as well as the wake flow could be properly predicted, but more refinement in numerical aspects are needed.

Experimental Investigation of Tip Clearance Flows of an Axial Flow Fan Using PDA

2002 ◽  
Author(s):  
Xiaocheng Zhu ◽  
Wanlai Lin ◽  
Zhaohui Du ◽  
Yan Zhao
Keyword(s):  
Flow Field ◽  
Reverse Flow ◽  
Axial Flow ◽  
Tip Clearance ◽  
Measurement Technology ◽  
Dynamics Modeling ◽  
Tip Leakage Flow ◽  
Axial Flow Fan ◽  
Tip Leakage Vortex ◽  
Tip Leakage

The three-dimensional flow field in the tip region of an isolated axial flow fan rotor with two different tip clearances are investigated using a three-color, dual-beam PDA system (Particle Doppler Anemometer, DANTEC Measurement Technology). The global performance is also obtained, and is compared favorably with CFD (Computational Fluid Dynamics) modeling of this fan flow at a zero tip clearance. The detailed flow field measurements are taken at 15 axial locations upstream, inside and at the exit of the rotor. In the radial direction, 15 measurement locations are arranged from 50% of the blade span to the casing wall, mainly focusing on the tip region from 90% of the blade span location to the casing wall (about 10 measurement locations). The PDA data has provided a quantitative understanding of the flow phenomena in the tip region of the fan rotor. For both tip clearances, it has been observed that the tip leakage flow rolls up into a tip leakage vortex. Due to the rotation of the rotor, this tip leakage vortex moves away from the suction surface of the fan blade. A reverse flow is induced in the main flow passage because of the tip leakage vortex. The depth and extent of the tip leakage vortex grow noticeably with the increase of the tip clearance.

161 Study on the flow field of a small axial flow fan in narrow spaces through LDV and PIV : Effect of tip clearance

2014 ◽  
Vol 2014.49 (0) ◽  
pp. 119-120
Author(s):  
Kouta CHIBA ◽  
Ken-ichi FUNAZAKI ◽  
Hideo TANIGUCHI ◽  
Yusuke MAKINO
Keyword(s):  
Flow Field ◽  
Axial Flow ◽  
Tip Clearance ◽  
Axial Flow Fan ◽  
Small Axial Flow Fan

The Measurement of Three-Dimensional Flow Field in an Axial Flow Fan Using PDA

2002 ◽  
Author(s):  
Zhaohui Du ◽  
Wanlai Lin ◽  
Xiaocheng Zhu ◽  
Yan Zhao
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Flow ◽  
Flow Fields ◽  
Tip Clearance ◽  
Measurement Technology ◽  
Particle Dynamic ◽  
Axial Flow Fan ◽  
Three Dimensional Flow ◽  
Dimensional Flow

In this paper, a three-color dual-beam PDA (Particle Dynamic Analyzer) system (made by DANTEC Measurement Technology) is used to measure the three-dimensional velocity of an axial flow fan. Due to the geometrical limit of fan rotor, non-orthogonal velocity components are measured first, from which the orthogonal three-dimensional components of the velocity field are computed through transformation equations. The detailed flow fields at 15 axial locations upstream, inside and at the exit of the rotor are measured, respectively. On each cross section perpendicular to the rotating axis, the flow field measurement at 15 different radial locations from 50% of the blade span to the region inside the tip clearance (between the tip blade and the casing wall) are taken. The experimental technique is described, and the three dimensional flow fields (including the tip clearance flow) are presented and analyzed.

Numerical Simulation on Axial Flow Fan Performance with Changing Tip Clearance

2013 ◽  
Vol 732-733 ◽  
pp. 577-580
Author(s):  
Zhou Ye ◽  
Hai Yang Zhao ◽  
Lu Zhang ◽  
Chun Li ◽  
Wei Gao
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Total Pressure ◽  
Great Influence ◽  
Axial Flow ◽  
Tip Clearance ◽  
Axial Flow Fan ◽  
Flow Solver ◽  
Fan Performance ◽  
Relative Value

Taking the relative tip clearance as the variable, we numerically simulated the effect of tip clearance size on the performance of a straight-blade axial flow fan using the 3-D viscous flow solver. The tip clearance is referenced in the relative value. By comparing the flow field corresponding to five different values of the tip clearance 0, 0.5%, 1.0%, 1.5% and 2.0% with other parameters kept constant, we concluded that the changing of the tip clearance has a great influence on the performance of the axial flow fan. Both the efficiency and the total pressure decrease with the increase of the tip clearance.

Numerical Simulation of the Effect of the Tip Clearance Flow on Rotor-Stator Interaction Tone Noise in Axial-Flow Fan

2020 ◽  
Author(s):  
Wang Liangfeng ◽  
Xiang Kangshen ◽  
Mao Luqin ◽  
Tong Hang ◽  
Qiao Weiyang
Keyword(s):  
Numerical Simulation ◽  
Power Level ◽  
Axial Flow ◽  
Leading Edge ◽  
Tip Clearance ◽  
Axial Flow Fan ◽  
Sound Sources ◽  
Tip Clearance Flow ◽  
Clearance Flow ◽  
Rotor Stator Interaction

Abstract The present study is focused on the sound generation due to the rotor tip clearance flow interaction with stator in an axial flow fan. A hybrid URANS/Goldstein’s equations method is applied to calculate the unsteady flow and tone noise in a high loaded axial-flow fan with different rotor tip clearance. The numerical simulation results show that the main sound sources of fan tip clearance tone noise are concentrated in the leading edge of downstream stator blades. It is found that when the rotor tip clearance increases from zero to 2.5 mm (0.94% relative blade height), the mass flow of the fan decreases by about 2% and the efficiency of the fan decreases by about 1 percentage, and the sound power level at 1BPF forward tone increases by 1.47dB, and that of backward tone increases by 0.65dB. However, the influence of tip clearance on the tone noise intensity at 2BPF and 3BPF is more complex, and the variation range is less than 1dB. It is found that the wake width and wake strength at the rotor exit increase with the increase of tip clearance. The tip secondary flow caused by rotor clearance seriously affects the circumferential inhomogeneity of stator leading edge inflow conditions.

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