How Axial-Flow Roof Fans Are Designed and Controlled

How Axial-Flow Roof Fans Are Designed and Controlled

Based on the aerodynamic design of axial-flow roof fans and experimental models of the obtained characteristic parameters, applying the same theoretical principles to selected axial-flow roof fans is crucial for rapidly selecting and correctly adapting to design requirements, effectively controlling stall phenomena, and expanding the propeller’s safe operating range. Importance. Based on the analysis of the locking mechanism and active locking control methods for axial flow roof fans, it is recommended to provide air with multiple inlets near the vortex tongue. For new axial flow roof fans commonly used in power stations, non-fixed constants are employed to simulate rotational loss phenomena. Experimental results indicate that the pre-blockage region exhibits distinct modal waveforms; as the propagation velocity increases, a blockage group is present. The cutoff frequency of the axial flow roof fan is consistent with the experimental results. By analysing the flow field dynamics at four typical instants before and after rotational stoppage, the circumferential propagation rules of the limiter are investigated. In the relative coordinate system, the limiter propagates in the direction opposite to the propeller’s rotation. An investigation into the laws governing total pressure variation curves in the shutdown zone indicates that the relative position of the shutdown unit and its propagation velocity are the primary causes of total pressure variation and frequency in the wind turbine. These findings are crucial for predicting rotational faults and active control. A discrete-phase model was employed to numerically simulate the motion trajectories of solid particles within the axial-flow roof fan, providing a qualitative simulation of their movement. The simulation results will aid future fan wear design. The discharge performance of axial-flow roof fans and axial-flow fans was tested under varying rotational positions and rotational speeds, providing reference values for the selection of parameters and series configurations of axial-flow roof fans. Accurate methods for predicting turbulence in axial-flow roof fans are crucial for research into these fans. This paper reviews the research on numerical simulation methods for analysing internal flow in axial-flow roof fans, provides a detailed introduction to the governing equations and computational methods for evaluation, and discusses their future applicability.