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

2021 ◽  
Vol 11 (16) ◽  
pp. 7715
Author(s):  
Yanbing Chi ◽  
Peiling Yang ◽  
Zixuan Ma ◽  
Haiying Wang ◽  
Yuxuan Liu ◽  
...  

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.

Author(s):  
Balaji Kannan ◽  
N. Janani ◽  
S. Thangamani ◽  
A. Selvaperumal

Irrigation water is many a time contaminated with physical, chemical and biological impurities. Proper filtration is of paramount importance to prevent clogging in drip irrigation system thereby aiding in reduced maintenance of the micro irrigation system. This study was conducted on Development and Evaluation of Low cost filters in the Network project on “Engineering Interventions in Micro Irrigation Systems (MIS) for improving water productivity” under Consortia Research Platform on Farm Mechanization and Precision Farming during 2018 to 2020. The objectives of the study are to develop low cost filters and to test the developed system in the field for efficiency in terms of pressure drop throughout discharge and quality of output. It was observed that the discharge from the filter increases as the time increases. Pressure drop and head loss in the filter system increases with flow rate. Filtration efficiency is a percentage of sand particles divided by the TSS removed by the filter. Efficiency of the filter increased from 25% to 64% (double chamber filter) and 23% to 62% (single chamber filter) with flow range of 5 m3/h to 30 m3/h. As flow rate increases, soil particles retained and efficiency of the filter increased with increase in head loss. Filter materials and screen filter removed the sand particles effectively. Uniformity coefficient of 0.95 was observed in single chamber filter which is suitable for small farm application.


Author(s):  
Amin Seyedzadeh ◽  
Amir Panahi ◽  
Eisa Maroufpoor ◽  
Abdolmajid Liaghat

Author(s):  
K. Nagarajan ◽  
S. Ramya ◽  
T. Thangamani ◽  
A. Selvaperumal ◽  
T. Arthi

The parameters require for maintaining the crop's health and the integrity of the irrigation system has a relation with quality of irrigation water. In Micro irrigation appropriate filtration is very much important to prevent clogging. Filtration unit is one of the main components in micro irrigation system that too, Primary filter is more important to be installed along with the unit, when the water source is from open reservoir and other water sources. Though it is essential, the primary filter is not being installed by the farmers due to its high cost. Hence this study is an attempt to fabricate low-cost filter and to evaluate its performance with different filter media layer. A low-cost primary filter for drip irrigation system is fabricated. Different filter media layer like silex sand (fine silex, coarse silex), pebbles with different sizes are selected. The results revealed that the removal efficiency of filter using silex sand and pebbles were 71% in terms of turbidity, 78% in terms of total suspended solids removal at flow rate of 12 m3 /hr. This fabricated low-cost filter will be cost effective for small farm applications.


2013 ◽  
Vol 30 (3) ◽  
pp. 805-830
Author(s):  
G. A. Sharaf ◽  
Azza Hassan ◽  
Hashem Mahmoud

Author(s):  
T A Fox ◽  
J Stark

This paper presents the results of an experimental investigation into the flow characteristics of miniature short-tube orifices of a type commonly used for fuel injection. From measurements of differential pressure and volumetric discharge it is shown that these devices are susceptible to a cavitation-induced instability phenomenon known as hydraulic flip. It was found that this instability is limited to orifices of length less than fourteen diameters and occurs at a critical pressure differential which varies as a function of the orifice l/d ratio and contraction parameter β. In addition, the performance of the device is examined in terms of the head loss characteristics and it is shown that the mechanisms associated with hydraulic flip have a significant effect on the efficiency of discharge.


2020 ◽  
Vol 12 (16) ◽  
pp. 6428
Author(s):  
Jaewon Yoo ◽  
Tan Hung Nguyen ◽  
Eungu Lee ◽  
Yunje Lee ◽  
Jaehun Ahn

Although the permeability of open-graded friction course (OGFC) materials in the transverse direction and the reduction in permeability associated with long-term traffic loading are important issues, they have remained under researched thus far. In this study, testing equipment and procedure were developed to evaluate the permeability of an OGFC specimen along the horizontal direction and its reduction due to rutting. Horizontal permeability tests were conducted by varying the hydraulic gradient of specimens with porosities of 19.6%, 15.6%, and 10.3%. The reduction in cross-section due to traffic loading was simulated via a wheel tracking test, and the permeability was subsequently evaluated. The reliability of test methodology was successfully verified; the tendency of the relationship between discharge velocity and hydraulic gradient was in good agreement with existing research results. The reduction in cross-sectional flow area due to rutting decreased and the horizontal permeability. The test results using developed testing equipment will enable efficient OGFC design.


2001 ◽  
Vol 124 (1) ◽  
pp. 263-272 ◽  
Author(s):  
K. Boomsma ◽  
D. Poulikakos

Open-cell aluminum foams were investigated using water to determine their hydraulic characteristics. Maximum fluid flow velocities achieved were 1.042 m/s. The permeability and form coefficient varied from 2.46×10−10 m2 and 8701 m−1 to 3529×10−10 m2 and 120 m−1, respectively. It was determined that the flowrate range influenced these calculated parameters, especially in the transitional regime where the permeability based Reynolds number varied between unity and 26.5. Beyond the transition regime where ReK≳30, the permeability and form coefficient monotonically approached values which were reported as being calculated at the maximum flow velocities attained. The results obtained in this study are relevant to engineering applications employing metal foams ranging from convection heat sinks to filters and flow straightening devices.


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