The Study on Internal Flow Characteristics of Disc Filter under Different Working Condition

Yanbing Chi,Haiying Wang,Yuxuan Liu,Zixuan Ma,Peiling Yang,Bingbing Jiang,Zongguang Hu

doi:10.3390/app11167715

Yanbing Chi, Haiying Wang + Show 5 more

Open Access

https://doi.org/10.3390/app11167715

Copy DOI

Abstract

A disc filter (DF) is an important component in a micro irrigation system. However, it has a high head loss and low filtration efficiency, which can lead to the inoperability of micro irrigation systems. To improve the filtration ability and to decrease the pressure loss of the irrigation system, it is necessary to internalize the hydraulic characteristics of DFs. In this study, the filter bed of a DF was divided into three parts, i.e., upper, middle, and lower, which were wrapped with a transparent film. The wrapped part was completely blocked. The purpose was to analyze the hydraulic characteristics of different clogged conditions in three types of filters under four types of flows. In addition, we attempted to simulate the filter operation process with computational fluid dynamics, based on two aspects—a macroscopic model and a simplified model. The results showed that the patterns of head loss among all of the DFs was consistent, and the macroscopic model that treated filter bed as a porous medium could express the measured results. The macroscopic models observed that there was a circular flow in the DF, and the flow velocity presented a symmetrical distribution in a horizontal direction. The middle of the filter element appeared in a high-pressure area and demonstrated the highest head loss, which may be the main flow area of the DF, and the inner flow characteristics of the DF were consistent under different conditions. The simplified models showed that the main flow area is near the filter bed in the inner DF, and the flow is tangent to the filter bed between 45 and 90 degrees in a horizontal direction. The uneven distribution of velocity and pressure on the filter bed might be necessary factors to impact filter efficiency.

Highlights

The application of inferior water inhibits the promotion of water-saving irrigation technology
This paper focused on exploring the inner flow characteristics of disc filter (DF) and their working mechanism through experiment and numerical simulation (CFD)
Our study considered that the assumed condition that the porous medium of the filter bed could be applied to DF simulation, but this assumption could have had an impact on the internal flow

Summary

Introduction

The application of inferior water inhibits the promotion of water-saving irrigation technology. Filters are the key piece of equipment that influences the energy consumption of micro irrigation systems and uniformity in irrigation systems [1,2], which can remove impurities to avoid emitter clogging and to maintain the operability of micro irrigation systems. A disc filter (DF) is commonly used as a secondary filter in a micro irrigation system to remove inorganic and suspended organic particles in water. The disadvantages of DFs are their complex flow path structure, low filtration efficiency, long backwash time [3], and higher head loss than sand and mesh filters [4]. The complicated structure of DFs have had a significant impact on visualization research, and they were not conducive to product optimization and performance improvement. It is very necessary to gather detailed information about the inner flow characteristics and working mechanisms

Methods

Results

Discussion

Conclusion