Session: 10-03 Design and optimization

Paper Number: 80256

80256 - Design of an Axial Flow Fan for a Unique Cooling Application 

A rotor-only axial flow fan is designed for use in a concentrated solar power plant. The plant uses a supercritical carbon dioxide Brayton cycle for power generation and an air-cooled heat exchanger (ACHE) for cooling. The fan’s performance is estimated numerically using a periodic three-dimensional model (P3DM) in both an annular computational domain and a computational domain representing a simplified ISO 5801 type A fan test facility. Experimental tests are performed in an ISO 5801 type A fan test facility.

Fan specifications are derived by considering the geometry and air flow rate requirements for the ACHE, using simple, circular finned tube bundles. The design-point flowrate is found to be lower than typically expected for an axial flow fan, leading to a fan design with a relatively large hub-to-tip ratio and a moderate rotational speed.

The annular domain numerical results show good agreement with the performance predicted by the design procedure, for cases with no tip gap present and with the design tip gap size. It also demonstrates the effect of reducing this design tip gap on the overall fan performance.

The simplified ISO 5801 type A fan test facility numerical results indicate that fan performance is significantly worse than in the annular domain, due to the large hub size of the fan being considered in this domain. The experimental results demonstrate the accuracy of the numerical method, while also investigating various ways of improving fan performance to meet the target performance.

Finally, the fan performance characteristics are used to estimate the actual flow rate in the air-cooled heat exchanger.

Presenting Author: Francois D. Boshoff University of Stellenbosch

Presenting Author Biography: I am a candidate for a Master of Engineering (Mechanical) degree at the University of Stellenbosch. My masters is on the design of an axial flow fan for use in a CSP plant.

Authors:

Francois D. Boshoff University of Stellenbosch
Sybrand J. Van Der Spuy University of Stellenbosch
Johannes P. Pretorius University of Stellenbosch
Christiaan J. Meyer University of Stellenbosch