## 5 Conclusions  
Slurry blast rust removal technology is a green production technology used for mechanically removing oxide scale on the surface of steel strips, which can avoid the serious problems of rapid wear, low service life, and low efficiency of the traditional AWJ nozzles in the field of steel strip descaling. The DPM and the erosion model are innovatively applied to simulate the movement characteristics of particles inside the rotating blade centrifugal jet and to study the influence of important system parameters on the flow field characteristics of the rotating jet. The effects of blade rotation speed and inlet pressure on descaling efficiency are investigated experimentally and compared with the simulation results. According to the simulation and experimental results, the following points could be concluded.  
1. The DPM is adopted to simulate the momentum and the energy of particles in a continuous phase and then obtain trajectory and particle velocity. The erosion model can simulate the erosion effect of particles on the rust layer and removal weight changes with time. The simulation results show that erosion locations are concentrated on the downwind area of the rotating blades on the steel plate, and erosion rates are mostly in the range of 0-3.0 \(\times\) 10\({}^{-8}\) kg/m\({}^{2}\).
2. The erosion rate and the particle velocity of the mixed slurry are proportional to blade rotation speed and inlet pressure. Impact force is increased by 3.4 times with the variation of different blade rotation speeds and is increased by 1.28 times with the increase in inlet pressure. Therefore, the larger blade rotation speed and reasonable inlet pressure should be adopted as much as possible to obtain a greater impact force and improve the efficiency of rust removal of slurry blast devices.  
Figure 12: Weight of rust removed between simulation and experiment at different blade rotation speed.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & **Inlet Pressure** & **Simulation** & **Simulation Impact** & **Experimental** \\  & **(MPa)** & **Velocity (m/s)** & **Force (N)** & **Impact Force (N)** \\ \hline
1 & 4 & 42.5 & 120.62 & 102.33 \\
2 & 6 & 46.5 & 132.97 & 112.17 \\
3 & 8 & 48.77 & 138.41 & 116.26 \\
4 & 10 & 51.32 & 147.65 & 122.43 \\
5 & 12 & 55.09 & 153.35 & 125.77 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Impact forces at different inlet pressure.  
3. The abrasive particle diameter has a minimal effect on erosion rate, and particle velocity decreases with the increase in particle diameter distinctly. Assuming that the rust layer of the steel plate can be completely removed, the smaller particle is an effective method to improve the particle velocity and the rust removal ability of the rotating blade centrifugal jet. 4. The weight of rust removed is proportional to blade rotation speed. When the rotation speed is 1470 rpm, the maximum weight of rust removed reaches 9.5 g/s. The experimental data are consistent with the simulation trends, which are approximately 85-95% of the simulation value. This paper will play remarkable guiding roles in the engineering optimization of slurry blast devices for steel strip descaling and the application to the surface treatment of other metal structures.