This report shows how we used computational fluid dynamics (CFD) to study erosion in a centrifugal fan using ANSYS Fluent. Centrifugal fans are very important in many industrial processes like cement making, power plants, and mining where they move air with lots of solid particles. These dust particles hit the fan blades and impeller at high speeds, causing material wear and surface erosion over time. In cement clinker production, industrial fans work in extremely erosive environments which damages the fan components and reduces fan performance. This kind of erosion prediction helps engineers design better turbomachinery with longer life and plan maintenance schedules more effectively. The multiphase flow simulation tracks both air movement and particle trajectories to show the most vulnerable areas on the impeller surface and fan housing. Thanks to the reference papers, a CFD study is conducted to investigate and model erosion on a centrifugal fan using ANSYS Fluent.

• Reference [1]: Aldi, Nicola, et al. “Erosion behavior on a large-sized centrifugal fan.” 13 th European Conference on Turbomachinery Fluid dynamics & Thermodynamics. European Turbomachinery Society, 2019.
• Reference [2]: Evaluation of the Wear-Resistant Plate Performance on Different Locations over the Flow Path of a Large-Sized Heavy-Duty Centrifugal Fan

Figure 1: Schematic diagram of an centrifugal fan

Simulation Process

The model geometry is primarily designed by Design Modeler. Due to the complexities of the model, Fluent Meshing tool is utilized to perform an unstructured grid. It goes without saying that the rotational motion of the impeller can be applied using Multi Reference Frame (MRF) module. Thus, two separate zone have to be designed: rotational & stationary. The main focus of the study is on erosion. So inevitably, Discrete Phase Model (DPM) and Erosion/Accretation submodel are enabled. To some extent, the small dust particles cannot influence the air (continuous phase), leading to 1-way DPM approach. Further, Saffman lift force is included.

Figure 2: Geometry model designed for CFD analysis

Post-processing

The velocity contour in the stationary frame (Figure 3) reveals the complex flow structure within the centrifugal pump. The highest velocities (120-160 m/s, orange-red regions) occur at the impeller blade tips where the fluid receives maximum energy transfer from the rotating component. This creates a strong velocity gradient moving outward from the center. The volute casing shows a gradual velocity decrease (green-blue regions, 40-80 m/s) as the flow area increases, converting kinetic energy to pressure. This contour clearly shows how the blade geometry directs flow, with the curved blades accelerating fluid from the low-velocity hub (blue, 0-20 m/s) to high-speed regions at the periphery. The design appears effective at maintaining relatively uniform velocity distribution around the impeller circumference, though small variations in the color pattern between blade passages suggest minor flow imbalances that could contribute to uneven pressure loading.

Figure 3: Velocity contour in stationary reference frame

The streamline visualization (Figure 4) provides deeper insights into the actual flow paths and recirculation zones. The central inlet flow enters with relatively low velocity (blue streamlines, 0-30 m/s) before being drawn into the rotating impeller where it accelerates significantly (green-yellow, 60-100 m/s). Particularly notable are the multiple vortex structures visible between impeller blades and in the volute, appearing as swirling blue patterns. These recirculation zones indicate potential flow instabilities that correlate directly with the erosion risk areas shown in Figure 3. The DPM erosion rate contour identifies concentrated erosion hotspots (red-yellow regions, 2.5-3.8×10⁻⁵ kg/m²s) primarily at three locations within the pump: the leading edges of impeller blades, the cutwater region where flow from the impeller enters the discharge area, and specific zones along the volute wall. This erosion pattern matches the flow behavior shown in the streamlines, where high-velocity particulate flow impacts surfaces at sharp angles or where recirculation zones cause repeated particle impacts. These results suggest design modifications should focus on smoothing flow transitions at the cutwater and potentially redesigning blade leading edges to reduce particle impact angles.

Figure 4: Streamline visualization revealing complex flow paths

Figure 5: DPM Erosion Rate contour displaying predicted material removal rates