This project examines into erosion in a Stairmand cyclone separator, which is a major problem that affects commercial uses. Based on the reference work of Dizajyekan et al. (2022) called “Evaluation of Centrifugal Force, Erosion, Strain Rate, and Wall Shear in a Stairmand Cyclone,” this study uses computational fluid dynamics (CFD) to look at the intricate relationship between particle paths, flow patterns, and the erosion rates that happen inside the cyclone. The study’s goal is to find important erosion zones in the separator by modeling how grains particles move through the cyclone and looking at how different inlet speeds and mass flow rates affect erosion patterns. Understanding this is important for making sure that the design and operation of cyclones don’t cause damage, which in turn extends the life and performance of these important industrial parts.

• Reference [1]: Dizajyekan, Sajed Naiemi, et al. “Evaluation of centrifugal force, erosion, strain rate, and wall shear in a Stairmand cyclone.” Processes5 (2022): 994.

Figure 1: Schematic of cyclone separator [1]

Simulation Process

Table 1 [1] represents the cyclone’s sizes that were used in the numerical study. This cyclone is a Stairmand cyclone with a tangential entrance part that has a high separation efficiency. It is primarily designed using ANSYS Design Modeler. Then, the model is meshed in ANSYS Meshing, resulting in a structured grid that is established from 228225 cells (see Fig.2). In this study, the Reynolds stress model (RSM) was used to model the turbulence of the flow. It is a 7-equation model that has an undeniable accuracy in predicting turbulent effects, following by sweeping changes in computational cost. Additionally, the Discrete Phase Model (DPM) is based on modeling the particle–fluid interactions by the Lagrangian approach. The fluid and dispersed phases could exchange momentum, mass, and energy. Needless to say, the Erosion/Accretion sub-model is also activated. Both phases are solved considering unsteady (transient) solver.

Figure 2: Structured grid over cyclone separator

Post-processing

Discrete Phase Modeling (DPM) was used to look at erosion in the Stairmand cyclone separation. At the bottom of the conical component and along the vortex finder, the erosion rate is 1.31e+00 kg/m^2s, which means these are the most likely places to get damaged. The path of the particles inside the cyclone is directly responsible for this concentrated erosion. The particles are pushed toward the wall by centrifugal forces, which cause high-speed impacts in the cone-shaped section as they spiral downward. At the same time, the vortex finder is being broken down a lot by the focused stream of particles leaving the cyclone. This specific wear shows how important it is to choose the right material and think about design in these key areas to keep the separator from failing and make it last longer. It’s important to note that the measured pressure drop of 416.10 Pa highlights the energy loss caused by the swirling flow and particle-wall interactions, which affects how well the cyclone works overall.

Figure 3: Erosion rate inside cyclone separator CFD Simulation

The pattern of fluid flow, which is shown by vorticity and velocity levels, gives us more information about how erosion works. High vorticity magnitudes (above 2.98e+03 s^-1) near the vortex finder and along the walls of the cyclone show strong spinning motion. This rotating flow makes particle-wall interactions stronger, which helps explain the limited erosion seen in these spots. It’s even more likely that this is true because the velocity magnitude contour shows peak values of 2.09e+01 m/s near the opening and outer wall. When particles hit at high speeds and the vorticity field causes spinning motion, it makes an environment that goes away quickly, especially in the cone-shaped part and close to the vortex finder. For this reason, knowing how particle dynamics and fluid flow traits affect each other is very important for predicting and reducing erosion in cyclone separators, which leads to better performance and longer life for these machines.

Figure 4: Velocity Magnitude inside cyclone separator