# Influence of Fractal Disc Filter Flow Channel Parameters on Filtration Performance
## 1 Introduction  
In recent years, the vigorous development of information technology and big data [1] has continuously promoted the transformation of traditional water conservancy to smart water conservancy. At the same time, the irrigation rate of cultivated land in China is as high as 51%, 2.68 times the world average of 19% [2]. Under the background of the rapid development of agricultural production and irrigation science and technology [3], smart irrigation is increasingly welcomed by farmers. With the support of massive agricultural information and data, the use of artificial intelligence and the Internet of Things (AI+IOT) can solve the inefficiency of traditional agriculture [4, 5], improve the efficiency of fine operations, and realize fine irrigation, intelligent fertilization, and pest and disease identification. This will not only promote the development of accurate, efficient, and green agriculture but also improve the level of agricultural information and intelligence and provide technical support for the expansion of the agricultural Internet of Things. The disc filter is a key part of the intelligent irrigation system, and its characteristics of accurate filtration, thorough and efficient backwashing, automatic operation, and continuous water discharge provide an important guarantee for pollution control, farmland irrigation water quality, and irrigation efficiency. In order to improve the filtration effect and work efficiency of disc filters in intelligent irrigation systems, a large number of scholars have improved the macrostructure of disc filters. [PERSON] et al. [6] combined a sand filter and a disc filter to design a laminated sand filter. The new product has a large filtration capacity and a small head loss. [PERSON] et al. [7] proposed a new type of stacked mesh filter for agricultural drainage and irrigation that is simple in structure and far exceeds the performance index of similar domestic filters. [PERSON] et al. [8] developed a hydraulic piston disc filter with a transparent shell, which has a more uniform head loss and growth range; [PERSON] [9] designed a set of water flow and sediment separation systems basedon centrifugal and disc filters, and the filtration effect has been significantly improved. [PERSON] et al. [10] conducted a DPM model-based numerical simulation study on rectangular and triangular groove laminators, respectively, and found that the triangular groove disc filter had small head loss, uniform flow rate distribution, and high filtration efficiency. [PERSON] et al. [11] found that the laminated thickness and section bottom angle of the disc filter affect its flow capacity, while the tilt angle has almost no effect on the filter head loss. [PERSON] et al. [12] combined the disc filter with the sand and gravel filter, and found that the combination increased the removal rate by about 20% after filtering the reclaimed water. [PERSON] et al. [13] fuse two kinds of flow passage with different mesh numbers into one stack, and the results show that the composite flow passage stack has less head loss. [PERSON] et al. [14] tested the filtering performance of a disc filter with clay and sand particles and found that the filtration efficiency of sand is higher than that of clay with a certain flow range in the filter. The fractal theory was first proposed by [PERSON] [15] to describe binding objects with extremely irregular shapes. At the same time, the fracture theory is suitable for small-scale scientific research and is widely used in microflow passage [16; 17]. The flow state inside the disc filter is turbulent, and the internal flow [18] channel is complicated and difficult to observe directly. Therefore, the fractal theory can be used to optimize the structure of the disc filter's internal micro-channel. [PERSON] et al. [19] used the fractal curve to construct a more complex flow passage boundary in the design of the emitter's labyrinth flow passage, which reduced the flow index of the emitter. By using the simplified Koch Fractal curve, [PERSON] et al.