# Influence of Fractal Disc Filter Flow Channel Parameters on Filtration Performance
## 3 Results and Discussion
### Influence of Single Flow Passage Parameter on Filtration Performance
#### 3.1.2 The Tilt Angle  
With the increase in flow passage inclination angle, the flow capacity of the laminate is gradually increased. Under the same inlet pressure, the larger the flow capacity of the stack, the better the filtration performance of the disc filter. Therefore, from the perspective of flow capacity, under the condition that the flow passage exit section is complete, the stack with a tilt angle of 35\({}^{\circ}\) is better than the stack with a tilt angle of 23\({}^{\circ}\). In order to verify the above conclusions and conveniently observe the changes in velocity and turbulent kinetic energy in the flow passage, five different cross sections were selected for observation. The locations of cross sections are shown in Figure 8, and the velocity and turbulent kinetic energy cloud images of each section are shown in Figures 9 and 10.  
According to the presented color distribution in Figures 9 and 10, the velocity nephograms of different flow passage inclination angles show that the maximum velocity of the 35\({}^{\circ}\) inclination angle is located at the center of the flow passage exit, and the velocity is about 0.95 m/s. The maximum flow rate of the flow passage at a 23\({}^{\circ}\) inclination angle is also located at the center of the flow passage exit, with a maximum of 0.88 m/s. The lowest flow rate for both tilt angles is located at the edge of the flow passage and can be as low as 0 m/s. The high flow rate in the main stream area reduces the risk of clogging the filter in the early stage of operation, so that the filter has a longer running time, while the low flow speed near the wall reduces the sand-carrying capacity of the water here, which can effectively deposit sediment and improve the filtration efficiency of the disc filter. By comparing the velocities of the two inclined angle laminar sections at the 1-0 section (the section where the buffer slot is located), it is found that the velocity in the main flow zone of the 23\({}^{\circ}\) flow passage changes obviously, but there is no mixing phenomenon in the main flow zone between different flow passages. The 35\({}^{\circ}\) flow passage maintains a high speed in the transition region where the two main flow regions are connected, except for the obvious changes in the main flow region. It shows that the 23\({}^{\circ}\) laminated buffer slot only increases the overflow area and promotes sediment deposition, while the 35\({}^{\circ}\) laminated buffer slot not only promotes sediment deposition but also exchanges water flow between different flow passages. By comparing the turbulent kinetic energy of the two tilting angle laminators, it is found that the turbulent kinetic energy in the mainstream flow region is 0.0012 (0.00012  
area is the lowest and increases from the middle to the periphery. The turbulent kinetic energy strength of the 35\({}^{\circ}\) stack is greater than that of the 23\({}^{\circ}\) stack after passing through the buffer groove. According to the comparison and analysis of the flow velocity cloud map, although the turbulence intensity in the mainstream area is small, the sand particles will not be deposited because of the high flow velocity. Near the wall, the turbulent kinetic energy of the 35\({}^{\circ}\) dip angle is not much different from that of the 23\({}^{\circ}\) dip angle, so it will not affect the sediment deposition.  
The above results show that the lamination with a 35\({}^{\circ}\) inclination is superior to the lamination with a 23\({}^{\circ}\) inclination before optimization. The filter performance of a disc filter is better when the flow passage angle is 35\({}^{\circ}\).