  An axial flow cooling fan has been designed for use in a concentrated solar
power plant. The plant is based on a supercritical carbon dioxide (sCO2)
Brayton cycle, and uses a forced draft air-cooled heat exchanger (ACHE) for
cooling. The fan performance has been investigated using both computational
fluid dynamics (CFD) and scaled fan tests. This paper presents a CFD model that
integrates the fan with the heat exchanger. The objective is to establish a
foundation for similar models and to contribute to the development of efficient
ACHE units designed for sCO2 power cycles. The finned-tube bundle is
simplified, with a Porous Media Model representing the pressure drop through
the bundle. Pressure inlet and -outlet boundary conditions are used, meaning
the air flow rate is solved based on the fan and tube bundle interaction. The
flow rate predicted by the CFD model is 0.5% higher than the analytical
prediction, and 3.6% lower than the design value, demonstrating that the
assumptions used in the design procedure are reasonable. The plenum height is
also found to affect the flow rate, with shorter plenums resulting in higher
flow rates and fan efficiencies, and longer plenums resulting in more uniform
cooling air flow.
