Session: 10-01 Experimental Aerodynamics of Fans

Submission Number: 177244

The Effect of Test Configurations on the Performance of an Axial Flow Fan 

Large-diameter axial flow fans are primarily used for cooling applications, such as in air-cooled heat exchangers. Experimentally testing these fans in controlled environments, such as fan test facilities, is important for evaluating their performance. This also allows for smaller, scaled-down models of fans to be tested instead of full-scaled fans which are difficult to test.

To ensure consistent results across different institutions, international standards are followed when conducting tests on axial flow fans. One such standard is ISO 5801:2007 [1], which outlines procedures for performance testing of fans using standardized airways. ISO 5801:2007 defines five fan installation categories, labelled Type A through Type E, type A: free inlet and free outlet, type B: free inlet and ducted outlet, type C: ducted inlet and free outlet, type D: ducted inlet and ducted outlet, and type E: free inlet and free outlet without a partition.

It is essential that the experimental tested performance characteristics are representative of the performance of the axial flow fan during full-scale industrial operation. Therefore, the fan’s inlet and outlet configuration should be based as closely as possible to the configuration the fan will be in installation.

The purpose of this study is to evaluate the effect of fan installation configuration on the performance characteristics, blade loading, and flow field of an axial flow fan, with particular emphasis on pressure rise. The study compares the performance of a 0.63 m axial fan operating in a Type D test facility with that of a 0.626 m axial fan—scaled to 0.63 m—tested in a Type A configuration. The effect of a flow straightener on performance characteristics is also investigated in the Type D fan test facility. All tests are conducted using an optimized free-vortex axial flow fan design known as the MT-fan, which is based on the original M-fan developed by Wilkinson (2017) [2].

Results show that the Type A configuration predicts a higher pressure rise than the Type D facility, while power consumption remains constant. This leads the Type A facility to predict higher efficiencies. The static pressure coefficient along the blade was analysed, and it was found that the two facilities experience different blade loading distributions along the blade length. This difference is due to the inlet geometry in the Type A facility, allowing for higher inlet axial velocities near the blade tip, causing more flow to interact with higher radial segments of the blade where more work is done.

[1]           ISO 5801:2007 (2007). Industrial Fans - Performance Testing using Standardized Airways. International Standard, 2nd edn.

[2]           Wilkinson, M.B. (2017). The Design of an Axial Flow Fan for Air-Cooled Heat Exchanger Applications. Master’s thesis, Mechanical Engineering, Stellenbosch University, South Africa.

Presenting Author: Tristan Oliver Le Roux Stellenbosch University

Presenting Author Biography: Tristan Oliver Le Roux is a doctorate student at Stellenbosch University in South Africa. Tristan has completed his master's degree in Mechanical Engineering with the proposed topic, "Development of an Axial Flow Fan with Alternating Blade Lengths". After completing his master's degree in this topic, it was upgraded to a doctorate, where he is currently furthering this research.

Authors:

Tristan Oliver Le Roux Stellenbosch University
Sybrand Johannes Van Der Spuy Stellenbosch University
Chris Meyer Stellenbosch University