A numerical investigation on the performance improvement of axial-flow automotive cooling fan with beads

2020 ◽  
Vol 34 (8) ◽  
pp. 3317-3323
Author(s):  
K. H. Hur ◽  
B. A. Haider ◽  
C. H. Sohn
Keyword(s):  
Numerical Investigation ◽  
Performance Improvement ◽  
Axial Flow ◽  
Cooling Fan

Noise Reduction Analysis of Electronic Device Cooling Fan With Duct and Its Application Under Variable Working Conditions

2021 ◽  
Author(s):  
Zonghan Sun ◽  
Jie Tian ◽  
Grzegorz Liśkiewicz ◽  
Zhaohui Du ◽  
Hua Ouyang
Keyword(s):  
Noise Reduction ◽  
Working Conditions ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Reduction Method ◽  
Axial Flow ◽  
Pressure Level ◽  
Inlet Flow ◽  
Cooling Fan ◽  
Inlet Duct

Abstract A noise reduction method for axial flow fans using a short inlet duct is proposed. The pattern of noise reduction imposed by the short inlet duct on the axial flow cooling fan under variable working conditions was experimentally and numerically examined. A 2-cm inlet duct was found to reduce tonal noise. As the tip Mach number of the fan increased from 0.049 to 0.156, the reduction in the total average sound pressure level at 1 m from the fan increased from 0.8 dB(A) to 4.3 dB(A), and further achieved 4.8 dB(A) when a 1-cm inlet duct was used. The steady computational fluid dynamics (CFD) showed that the inlet duct has little effect on the aerodynamic performance of the fan. The results of the full passage unsteady calculation at the maximum flow rate showed that the duct has a significant influence on the suction vortexes caused by the inlet flow non-uniformity. The suction vortexes move upstream to weaken the interaction with the rotor blades, which significantly reduces the pulsating pressure on the blades. The sound pressure level (SPL) at the blade passing frequency (BPF) contributed by the thrust force was calculated to reduce by 36 dB at a 135° observer angle, reflecting the rectification effect of the duct on the non-uniform inlet flow and the improvement in characteristics of the noise source. The proper orthogonal decomposition (POD) of the static pressure field on the blades verified that the main spatial mode is more uniformly distributed due to the duct, and energy owing to the rotor-inlet interaction decreases. A speed regulation strategy for the cooling fan with short inlet duct is proposed, which provides guidance for the application of this noise reduction method.

Numerical Investigation on the Separated Flow of Axial Flow Stator in Diagonal Flow Fan

2010 ◽  
Author(s):  
Yoichi Kinoue ◽  
Norimasa Shiomi ◽  
Toshiaki Setoguchi ◽  
Kenji Kaneko ◽  
Yingzi Jin ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Axial Flow ◽  
Separated Flow

Part-Span Application of Sweep and Lean at Turbine Blade Tips: A Low Speed Experimental Cascade Study

2010 ◽  
Author(s):  
Bhaskar Roy ◽  
Anoop Prajapati
Keyword(s):  
Performance Improvement ◽  
Turbine Blade ◽  
Axial Flow ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Pressure Surface ◽  
Wall Boundary Layer ◽  
Performance Reduction ◽  
Application Potential ◽  
End Wall

This study is aimed at exploring the possibility of aerodynamic performance improvement by providing part-span forward sweep and lean near the tip regions of axial flow turbine rotor blades. Such aerodynamic benefits may have application potential in the uncooled LPT blades. The curved forward sweep and curved lean have been provided to 25% of the blade span near the tip in cascade, Three sets of cascades of the same turbine airfoil have been studied — (i) straight blades, (ii) part span swept blades and (iii) part span leaned blades. The cascade results show that swept blade gives a recovery of 20–25% loss in blade performance near the tip region at 0° and 10° incidences. The swept and leaned blades suppress the Cp perturbations (as seen in straight blades) at 0° and at 10° incidences, on the suction surfaces of turbine blade cascades. Comparatively the leaned blades show blade unloading, largely on the pressure surface, which leads to some performance reduction. The wake loss study shows reduction in wake losses for swept turbine blade at near tip region. The end-wall boundary layer measurements across the open tips demonstrate some aerodynamic improvement, near the tip regions, for parts-span swept and leaned blades.

PIV Measurements of the Effects of Geometric Scale on Electronics Cooling Axial Fan Flow

2007 ◽  
Author(s):  
Ronan Grimes ◽  
David Quin ◽  
Edmond Walsh ◽  
Jeff Punch
Keyword(s):  
Velocity Distribution ◽  
Axial Flow ◽  
Electronics Cooling ◽  
Thermal Design ◽  
Small Scale ◽  
Axial Fan ◽  
Flow Angle ◽  
Piv Measurements ◽  
Cooling Fan ◽  
Macro Scale

The emergence of highly functional portable electronic systems in recent times means that passive dissipation of heat in these devices may not be an option in the near future. Micro fan technology is currently being developed to address this emerging need. Past investigations by the current authors indicate that the reduction of scale of conventional electronics cooling fan design to the mini scale does not excessively impair the bulk pressure flow performance of the fan. However, the detailed velocity distribution at the outlet of mini scale axial flow fans is unknown, and so effective thermal design in systems which use mini scale fans may be difficult, as the designer does not know the path taken by the flow emerging from the fan. To address this issue, this paper presents PIV measurements performed at the outlet of a series of geometrically similar axial flow fans, whose diameters range from 120 to 6mm, and whose design is based on that of a commercially available macro scale electronics cooling fan. The measurements show that as fan scale is reduced, there is a significant change in the fan outlet velocity distribution, and a large increase in the outlet radial flow angle. As a result, a designer using a small scale axial flow fan must be aware that the region downstream of the fan, where one would normally expect high velocity flow, will in fact be uncooled. Therefore, components should be mounted radially downstream of the fan, where highest air velocities are shown to exist.

Numerical investigation of impeller trimming effect on performance of an axial flow fan

Energy ◽  
2014 ◽  
Vol 75 ◽  
pp. 534-548 ◽  
Author(s):  
Chunxi Li ◽  
Xinying Li ◽  
Pengmin Li ◽  
Xuemin Ye
Keyword(s):  
Numerical Investigation ◽  
Axial Flow ◽  
Axial Flow Fan
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