# Study on the Influence of Dust Removal Fan Structure Parameters on Dust Removal Performance
## 3 Numerical Simulation Scheme of Dust Removal Fan  
### Solve the Settings and Boundary Conditions  
In this paper, the CFD method is used for numerical simulation analysis of the internal flow field of the dust removal fan. The numerical simulation settings are as follows: As the process of rotation of the driven impeller driven by the airflow needs to be simulated, the model adopts transient calculation. The driven impeller rotation domain adopts the dynamic grid model; the mass of the driven impeller, the center of gravity coordinate, and the moment of inertia around the \(Z\) axis are set in the options of 6 DOF. Due to the use of transient simulation, the sliding grid model was used in the rotation domain of the driving impeller, and the speed was set to 2900 rpm. The continuous phase adopts air with a density of 1.225 kg/m\({}^{3}\) and a viscosity of 1.7894 \(\times\) 10\({}^{-5}\) N\(\cdot\)s/m\({}^{2}\). The inlet of the fluid domain is set as the velocity inlet. Because the design air volume of the dust removal fan is 400 m\({}^{3}\)/min, and the measured value is 396.309 m\({}^{3}\)/min, the inlet speed is set to 16.405 m/s, converted from the circular inlet diameter of 716 mm. The outlet of the fluid domain adopts the pressure outlet, and the outlet pressure is set to 0 Pa. The interface between the rotation area of the driving impeller and the driven impeller, and other flow areas, is set as interface. The no-slip boundary condition is adopted on the solid wall. In the solution control, the coupling of pressure and velocity adopts the Simple algorithm, and the discrete scheme adopts second-order upwind. Because the Realizable k-\(\epsilon\) model has good performance for rotating flow, boundary layer flow with strong inverse pressure gradient, shear flow, free flow, flow separation, and secondary flow, the internal structure and flow field of the wet dust removal fan studied in this paper are relatively complex. Therefore, the Realizable k-\(\epsilon\) model is selected to deal with the continuous flow of the gas phase. In  
Figure 3: Internal fluid domain model of dust removal fan. Figure 2: Dust removal fan impeller model. the simulation process, the convergence of the calculation is judged by monitoring the mean value of the total pressure of the outlet plane, the mean value of the outlet plane velocity, the mean value of the tangential velocity of the driven impeller, and the torque of the driven impeller. The discrete phase model (DPM) is only applicable when the particle phase volume fraction is less than 10%. In this paper, the total particle flow rate is set to 0.001 kg/s, the incident velocity is set to 3 m/s, and the incident plane is the circular entrance of the dust removal fan with a radius of 0.358 m. Thus, the theoretical dust concentration at the inlet of the dust removal fan should be 8.279 \(\times\) 10\({}^{-4}\) kg/m\({}^{3}\), while the particle density is 1550 kg/m\({}^{3}\). Therefore, the volume fraction of the discrete phase is much lower than 10%, allowing for the utilization of the DPM model. Once the flow field inside the dust removal fan converges, the dust particle parameters are set in the discrete phase model and the dust removal performance of the fan is numerically simulated. Considering the complexity of the dust removal process of the dust removal fan, the simulation is simplified as follows: it is assumed that the droplets from the nozzle have formed a layer of water film on the inner wall of the dust removal fan and the dust particles are captured when they collide with the side wall of the dust removal fan. Furthermore, it is assumed that the particle size of the dust particles is 10 \(\upmu\)m. The discrete phase parameters are set as follows: the surface was selected as the incident mode of the discrete phase, the incident location was chosen as the entrance plane of the dust removal fan, and the discrete phase material was designated as anthracite with a density of 1550 kg/m\({}^{3}\).