Lift and drag force measurements on basic models of low-speed axial fan blade sections

Abstract

This paper presents comparative data on the aerodynamic lift and drag of basic model representations of low-speed axial fan blade sections. Three main types of blades are investigated: flat plate, cambered plate and RAF6-E profiled airfoil. Lift and drag force are measured at three different Reynolds numbers (0.6 × 10⁵, 10⁵ and 1.4 × 10⁵) around the threshold value of 10⁵. The measurement data are compared to literature data. The aerodynamic force measurements reveal that, for Reynolds numbers below 10⁵, cambered plate blade sections can be superior to airfoil profiles in terms of aerodynamic efficiency, especially in the high-load range. The effect of leading edge bluntness is also investigated. Leaving the leading edge of cambered plates blunt, tends to be uncritical for low Reynolds numbers at angles of attack between 4° and 10° but is critical at angles between 0° and 4°.

Keywords

Airfoil cambered plate blade low Reynolds number axial fan low-speed fan

Get full access to this article

View all access options for this article.

References

Huang

. Characterizing computer cooling fan noise. J Acoust Soc Am 2003; 114: 3189–3200.

Vad

Horváth

Kovács

. Aerodynamic and aero-acoustic improvement of electric motor cooling equipment. Proc IMechE, Part A: J Power and Energy 2014; 228: 300–316.

Borges SS. CFD techniques applied to axial fans design of electric motors. In: Proceedings of the international conference on fan noise, technology and numerical methods (FAN2012), Senlis, France.

Gue

Cheong

Kim

. Development of low-noise axial cooling fans in a household refrigerator. J Mech Sci Technol 2011; 25: 2995–3004.

Regulation of the European Commission (EU) No. 327/2011, of 30 March 2011, implementing Directive 2009/125/EC of the European Parliament and of the Council of the European Union with regard to ecodesign requirements for fans driven by motors with an electric input power between 125 W and 500 kW. Off J Eur Union; 54: 8–21.

VDI Standard 3731 Blatt 2. Characteristic noise emission values of technical sound sources; fans November 1990.

Balla E and Vad J. Beamforming studies on basic models of low-speed axial fan blade sections. In: Proceedings of 12th European conference on turbomachinery – Fluid dynamics and thermodynamics, Stockholm, Sweden, 3–7 April 2017.

Balla

Vad

. Establishment of a beamforming dataset on basic models of low-speed axial fan blade sections. Period Polytechn-Mech Eng 2017; 61: 122–129.

Mueller TJ. Aerodynamic measurements at low Reynolds numbers for fixed wing micro-air vehicles. In: RTO AVT/VKI special course on development and operation of UAVs for military and civil applications, 13–17 September 1999. Belgium: Von Karman Institute for Fluid Dynamics.

10.

Carolus

. Ventilatoren, Wiesbaden: B. G. Teubner Verlag, 2003.

11.

AMCA Publications 211-13 Certified Rating Program - Product rating manual for fan air performance, August, 2013.

12.

Carmichael BH. Low Reynolds number airfoil survey. NASA Contractor Report 165803, vol. 1, November 1981.

13.

Mueller TJ and Burns TF. Experimental studies of the Eppler 61 airfoil at low Reynolds numbers. AIAA Paper 1982;#82-0345.

14.

Laitone EV. Aerodynamic lift at Reynolds numbers below 7 × 10⁴. AIAA J 1996; 34: 1941–1942.

15.

Laitone

. Wind tunnel tests of wings at Reynolds numbers below 70,000. Exp Fluids 1997; 23: 405–409.

16.

Wallis

. Axial flow fans, London: George Newnes Ltd., 1961.

17.

Gulyás A and Balczó M. Development of a small blower-type wind tunnel for educational purposes. In: 28th microCAD international multidisciplinary scientific conference, Miskolc, Hungary, 10 April–11 November 2014.

18.

Lewis

. Turbomachinery performance analysis, Oxford: Butterworth-Heinemann, 1996.

19.

Rossetti

Ardizzon

Pavesi

et al.

An optimum design procedure for an aerodynamic radial diffuser with incompressible flow at different Reynolds numbers. Proc IMechE, Part A: J Power and Energy 2010; 224: 69–84.

20.

Vad

Kwedikha

ARA

Jaberg

. Effects of blade sweep on the performance characteristics of axial flow turbomachinery rotors. Proc IMechE, Part A: J Power and Energy 2006; 220: 737–749.

21.

Hoerner

. Fluid-dynamic lift, 2nd ed. Bricktown, New Jersey, USA: Hoerner Fluid Dynamics, 1992.