Using Computational Fluid Dynamics to Simulate Multiple Axial Flow Fans in Air-Cooled Steam Condensers
The large number of axial flow fans used in modern dry-cooled power plant air-cooled steam condensers necessitates the use of simplified numerical models when simulating the perfromance of such a condenser. Three simplified fan models are presented and implemented using computational fluid dynamics (CFD). These are referred to as the pressure jump, actuator disc and extended actuator disc models. The paper compares the CFD results obtained using these three models to experimental results obtained on a multiple axial flow fan test facility. The test facility was configured in such a way that it could accommodate different fan platform heights to vary the level of inlet flow distortion for the facility. The simulations show that the general flow field adjacent to the facility is independent of the simplified fan model that is used in the CFD analysis. However, the predicted flow field directly upstream of the edge fan varies according to the method used to represent the fan. It is also found that the more sophisticated fan models give a more accurate estimate of fan operation at higher levels of inlet flow distortion than the less sophisticated fan models.