scholarly journals Numerical simulation of the effects of sandy water on regulator labyrinth channel in micro-sprinkler systems

2021 ◽  
Author(s):  
Lin Hua ◽  
Hong Li ◽  
Chen Chao ◽  
Jiang Yue ◽  
Zhang Zhonghua
Keyword(s):  
Multiphase Flow ◽  
Particle Diameter ◽  
Sprinkler Irrigation ◽  
Sediment Concentration ◽  
Sand Particle ◽  
Operating Pressure ◽  
Discrete Phase Model ◽  
Irrigation Systems ◽  
Turbulent Dissipation ◽  
Labyrinth Channel

Abstract The effects of sandy water on the W-shaped labyrinth channel of micro-sprinkler irrigation systems with large flowrate were investigated using Computational Fluid Dynamics (CFD). Using ANSYS FLUENT software and different inflow conditions (e.g., pressure, velocity, sediment concentration, and sand particle diameter), internal turbulent multiphase flow and sand deposition were simulated by the Eulerian multiphase flow model. Particle erosion in the labyrinth channel was calculated by the Discrete Phase Model (DPM). The results show that vortex movements and shear actions at the boundary layer cause self-flushing in the channel. The location of sand particle deposits and the turbulent dissipation rate are related to the operating pressure, which is optimal at 300 kPa. The erosion rate of the channel wall is proportional to the inflow sediment concentration but has no obvious relationship with inflow velocity. Based on the movement regulation of sand particles in the labyrinth channel, recommendations on filtration requirements and operating pressure of irrigation systems are proposed.

Experimental and Numerical Investigation on the Erosion Wear of an Impact Sprinkler

2014 ◽  
Author(s):  
Yuncheng Xu ◽  
Guan Lin ◽  
Haijun Yan
Keyword(s):  
Internal Flow ◽  
Internal Surface ◽  
Sprinkler Irrigation ◽  
Sediment Concentration ◽  
Western China ◽  
Erosion Wear ◽  
Discrete Phase Model ◽  
Discrete Phase ◽  
The Cost ◽  
The Impact

In the middle and western China, agricultural irrigation water often contains a high sediment concentration. In order to save the cost, no filtration devices are required for sprinkler irrigation, which results in the wear of sprinkling irrigation equipment, especially on the nozzle. In this study, experiments on the erosion wear of an impact sprinkler (PY1-20sh with aluminum alloy nozzles) were conducted under different conditions of sediment concentration and erosion time. Using the experimental data as boundary conditions, numerical simulations based on the discrete phase model (DPM) were conducted to analyze the wear of the internal surface of the sprinkler’s full flow passage. Based on both experimental and numerical results, the erosion wear mechanism of the internal flow surface was revealed, and prediction model of the nozzle’s wear rate was established, providing the technical guidance for design and operation of the impact sprinkler.

scholarly journals Evaluation of uniformity coefficients for sprinkler irrigation systems under different field conditions in Kurdistan Province (Northwest of Iran)

2010 ◽  
Vol 5 (No. 4) ◽  
pp. 139-145 ◽  
Author(s):  
E. Maroufpoor ◽  
A. Faryabi ◽  
H. Ghamarnia ◽  
G.Y. Moshrefi
Keyword(s):  
Statistical Model ◽  
Field Effect ◽  
Sprinkler Irrigation ◽  
Rain Gauge ◽  
Field Conditions ◽  
Operating Pressure ◽  
Irrigation Systems ◽  
Uniformity Coefficient ◽  
Northwest Of Iran ◽  
Coefficient Of Uniformity

In the past few decades, several coefficients of uniformity were developed to express the uniformity of water distribution for different sprinkler irrigation systems. Christiansen's uniformity coefficient seems to be the most popular uniformity coefficient used by researchers on the global scale. However, more coefficients have also been proposed by other researchers. Therefore, this study focused on evaluating different uniformity coefficients proposed and on investigating the effects of field conditions on the results obtained by means of those coefficients. In doing so, sprinkler uniformity tests were conducted by using rain-gauge in order to measure the uniformity coefficients of ten fields irrigated by solid set sprinkler irrigation systems in Dehgolan Plain located in the Kurdistan Province, northwest of Iran. All fields selected differed in prevailing conditions such as the wind speed, size and type of nozzle, raiser height, operating pressure and sprinklers spacing. The coefficient of uniformity for each field was computed using the equations proposed by Christiansen (1942), Hawaiian Cane Society Specialists Hart and Reynolds (1965), Wilcox and Swailes (1947), Karmeli (1978), Criddle et al. (1956), Benami and Hore (1964), and Beale (1966). Data analysis was performed using the general linear model procedure of Statistical Analysis System Software. The results indicated that should not the field effect be considered in the statistical model, significant differences (P < 0.05) would be observed between the aforesaid coefficients; however, by considering the field effect in the statistical model, no significant differences (P > 0.05) would be observed. The results of this study conclusively indicated that the application of various coefficients of uniformity depends on the field conditions and as any specific coefficient of uniformity is suitable only for specific field conditions.

scholarly journals Enhanced discrete phase model for multiphase flow simulation of blood flow with high shear stress

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042110080
Author(s):  
Zheqin Yu ◽  
Jianping Tan ◽  
Shuai Wang
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Multiphase Flow ◽  
Experimental Verification ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Phase Model ◽  
Force Model ◽  
Discrete Phase Model ◽  
Discrete Phase

Shear stress is often present in the blood flow within blood-contacting devices, which is the leading cause of hemolysis. However, the simulation method for blood flow with shear stress is still not perfect, especially the multiphase flow model and experimental verification. In this regard, this study proposes an enhanced discrete phase model for multiphase flow simulation of blood flow with shear stress. This simulation is based on the discrete phase model (DPM). According to the multiphase flow characteristics of blood, a virtual mass force model and a pressure gradient influence model are added to the calculation of cell particle motion. In the experimental verification, nozzle models were designed to simulate the flow with shear stress, varying the degree of shear stress through different nozzle sizes. The microscopic flow was measured by the Particle Image Velocimetry (PIV) experimental method. The comparison of the turbulence models and the verification of the simulation accuracy were carried out based on the experimental results. The result demonstrates that the simulation effect of the SST k- ω model is better than other standard turbulence models. Accuracy analysis proves that the simulation results are accurate and can capture the movement of cell-level particles in the flow with shear stress. The results of the research are conducive to obtaining accurate and comprehensive analysis results in the equipment development phase.

scholarly journals AGRONOMIC CHARACTERISTICS OF THE PACOVAN ORGANIC BANANA IN IRRIGATION SYSTEMS IN THE AÇU-RN VALLEY

2018 ◽  
Vol 31 (2) ◽  
pp. 370-378
Author(s):  
JÚLIO JUSTINO DE ARAÚJO ◽  
VANDER MENDONÇA ◽  
MARIA FRANCISCA SOARES PEREIRA ◽  
MATHEUS DE FREITAS SOUZA
Keyword(s):  
Irrigation System ◽  
Block Design ◽  
Sprinkler Irrigation ◽  
Tropical Region ◽  
Irrigation Systems ◽  
Banana Production ◽  
Banana Tree ◽  
The One ◽  
Small Producers ◽  
Alternative Irrigation

ABSTRACT The banana tree is grown in an extensive tropical region throughout the world, usually by small producers. The present work had the objective of evaluating irrigation systems in banana production in the Açu-RN Valley, aiming at alternatives so that they can be recommended to farmers in the Açu Valley region. The experiment was carried out in the area of the School Farm of the IFRN Campus Ipanguaçu, located in the municipality of Ipanguaçu-RN. The experiment was carried out in a randomized complete block design with subdivided plots and eight replications. The irrigation systems were: irrigation, drip irrigation, micro sprinkler and alternative irrigation. The plots were composed of eight useful plants with spacing in double rows 4 x 2 x 2 m. Eight characteristics related to production were evaluated: bunch mass (MC); number of leaves (NP); number of fruits per cluster (NFC); mean mass of the leaves (MMP); diameter of the fruit of the second seed (DF2P); length of the fruit of the second seed (CF2P); mean fruit mass (MMF); productivity (Prod). The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% of probability. In the first cycle of production the sprinkler irrigation system was the one that presented better results the productivity of the Pacovan banana tree; in the 3rd cycle the alternative irrigation system was the one that showed better results the productivity of the banana tree; where the electrical conductivity correlated with the sodium adsorption ratio in the irrigation water, contributed to a moderate limitation of use.

Soybean Yield and Yield Component Response to Limited Capacity Sprinkler Irrigation Systems

jpa ◽  
1988 ◽  
Vol 1 (3) ◽  
pp. 196-201 ◽  
Author(s):  
R. W. Elmore ◽  
D. E. Eisenhauer ◽  
J. E. Specht ◽  
J. H. Williams
Keyword(s):  
Sprinkler Irrigation ◽  
Yield Component ◽  
Limited Capacity ◽  
Irrigation Systems ◽  
Soybean Yield

Mixing in Sprinkler Irrigation Systems

1974 ◽  
Vol 17 (6) ◽  
pp. 1020-1024
Author(s):  
G. J. Hermann ◽  
G. M. McMaster ◽  
D. W. Fitzsimmons
Keyword(s):  
Sprinkler Irrigation ◽  
Irrigation Systems

Assessment of an Eulerian multi-fluid VOF model for simulation of multiphase flow in an industrial Ruhrstahl–Heraeus degasser

2019 ◽  
Vol 116 (6) ◽  
pp. 617
Author(s):  
Gujun Chen ◽  
Qiangqiang Wang ◽  
Shengping He
Keyword(s):  
Multiphase Flow ◽  
Molten Steel ◽  
Mixing Time ◽  
Interface Tracking ◽  
Discrete Phase Model ◽  
Eulerian Model ◽  
Ansys Fluent ◽  
Vof Model ◽  
Discrete Phase ◽  
Sharp Interfaces

An Eulerian multi-fluid VOF model, the coupling of the Eulerian model and the “VOF” interface tracking method, offered by ANSYS Fluent has been first applied to investigate the complex multiphase flow in an industrial Ruhrstahl–Heraeus (RH) degasser. The idea of this study is to use the Eulerian model in the regions of the domain where the argon bubbles are dispersed in molten steel; in the regions of the domain where the sharp interfaces between the steel and slag or argon are of interest, the “VOF” method is adopted. The calculated flow characteristic, mixing time and circulation flow rate of molten steel in the RH degasser agree well with the observations reported in literature. Compared with the widely accepted Eulerian method and the discrete phase model–volume of fluid (DPM–VOF) coupled method, the Eulerian multi-fluid VOF model demonstrates the suitability for modeling the multiphase flow in the RH degasser where both dispersed and sharp interfaces are present.

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