Flow Characteristics in Energy Dissipation Units of Labyrinth Path in the Drip Irrigation Emitters with DPIV Technology

Liu, Haisheng; Li, Yunkai; Liu, Yan-zheng; Yang, Peiling; Ren, Shumei; Wei, Runjie; Xu, He-Yong

doi:10.1016/s1001-6058(09)60038-x

Cited by 32 publications

(34 citation statements)

References 8 publications

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“…It showed that velocity distribution in the same section had the trend of declining from the center to the side of the path, and the magnitude of the velocity in mainstream region was higher than the flow stagnation region. The velocity characteristics were the same as the result of Liu [10], who observed the flow field with DPIV (Digital Particle Image Velocimetry) technology. The velocity distribution characteristics mean that the two models were suitable to obtain the digitization of the flow field in the drip irrigation emitter.…”

Section: Model Verification and Selectionmentioning

confidence: 57%

“…LIU [10] employed the DPIV technology to identify that it is easy to happen clog for flow stagnation regions of emitters. Due to the similarity of the flow path structural unit and the velocity distribution in different sections [14], the different cross sections in the same structural unit were selected to analyze the velocity distribution characteristics in the article.…”

Section: Discussionmentioning

confidence: 99%

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Simulation of the flow characteristics of a drip irrigation emitter with large eddy methods

Liu

et al. 2013

Mathematical and Computer Modelling

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a b s t r a c tRealizing the internal flow visualization inside the drip irrigation emitter is the basis of optimizing the labyrinth path structure and promoting its anti-clogging capability. The Computational Fluid Dynamics (CFD) method has become an effective approach to research the water movement in the labyrinth path of the drip irrigation emitter. In this paper, the standard k-ε model and the Large Eddy Simulation method (LES) were applied to analyze the flow characteristic in the drip irrigation emitter. The results showed that the LES model was more effective to simulate the flow characteristics in the flow path of drip irrigation emitters. Based on this model, the energy dissipation mechanism was explained with the velocity and pressure values from local regions to the whole flow path, and the study of the flow path anti-clogging performance was carried out by way of analyzing the velocity distribution characteristics in different cross sections of the same structure unit.

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Section: Model Verification and Selectionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Simulation of the flow characteristics of a drip irrigation emitter with large eddy methods

Liu

et al. 2013

Mathematical and Computer Modelling

Self Cite

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“…Tracing particles were customized fluorescence polystyrene particles, of which the density was 1.02 kg m À3 and concentration 1-2%. The TSI insight 3G software (TSI, Inc., Shoreview, Minn.) was used for image acquisition and analysis, and the time interval of image sampling was 0.01 s. The specific testing steps of DPIV were shown in Liu et al (2009). Under pressure of 100 kPa, the velocity vector distributions calculated by the standard k-ε model were compared with that acquired by DPIV, as shown in Figure 2 (a).…”

Section: Model Verificationmentioning

confidence: 99%

Flow Characteristics and Pressure‐Compensating Mechanism of Non‐Pressure‐Compensating Drip Irrigation Emitters

Zhangzhong

Yang

Ren

et al. 2015

Irrigation and Drainage

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The flow regime index (x) is a key parameter for evaluation of the drip irrigation capacity of emitters. Developing an emitter with low x has become the goal for numerous emitter developers. Currently, the phenomenon shows that the x of some nonpressure-compensating (non-PC) drip irrigation emitters are less than 0.5, which cannot be easily explained by the macropipeline hydraulic principle. Therefore, in this paper, we adopted the standard k-ε model to calculate and analyse the internal flow field of four non-PC emitters (with x all less than 0.5). The results indicated that the flow fields within these flow paths had obvious self-compensating effects. It showed that when work pressure increased, the flow characteristics changed correspondingly: the area of the low-speed vortex region expanded incrementally, resulting in shrinkage of the width of the flow crosssection in the high-speed mainstream region, also inhibiting the increments of emitter outflow rates and alleviating the influence of pressure variation on outflow raters, and finally reducing the value of x. When the pressure increased from 10 to 150 kPa,the maximum shrinkage of flow cross-section (R max , the flow cross-section shrinkage rate under the work pressure, increased from 10 to 150 kPa) of emitters S1, M1, M2 and M3 was 32.0, 16.4, 13.8 and 10.3%, respectively. R max had a significantly negative linear relationship with x. As R max increased, the adjustment range of the flow cross-section became greater and sensitivity of the regulating flow improved. Then the x of the non-PC emitter declined, indicating higher self-compensating capacity of the emitter. Copyright © 2015 John Wiley & Sons, Ltd. Ils ont montré qu'en cas d'augmentation de la pression, les caractéristiques de l'écoulement sont modifiées comme suit: le domaine de la zone de vortex à basse vitesse s'étend de façon incrémentielle, ce qui entraîne le rétrécissement de la largeur de la section d'écoulement à grande vitesse, ce qui par voie de conséquence inhibe les augmentations du débit de sortie des émetteurs tout en atténuant l'influence de la variation de pression sur l'écoulement. A la fin, la valeur de x est réduite. Lorsque la pression a augmenté de 10 à 150 kPa, la contraction maximale de section transversale d'écoulement (R max ) des quatre émetteurs S1, M1, M2 et M3 était de 32.0, 16.4, 13.8 a été agrandie et la sensibilité de réglage de débit améliorée. Ensuite, le x de l'émetteur non compensé a diminué, ce qui démontre la capacité d'autocompensation de l'émetteur.

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“…3, the surface topographical characteristics of biofilms inside the unit, unit segments and multilevel unit segments at three levels were monitored (Liu et al 2010). The unit means the smallest and repeatable structure of the labyrinth flow path (e.g., site 1-5 in Fig.…”

Section: Selection Of Monitoring Sitesmentioning

confidence: 99%

Preliminary surface topographical characteristics of biofilms attached on drip irrigation emitters using reclaimed water

Zhou

Liu

et al. 2012

Irrig Sci

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Drip irrigation is the most effective and reliable method for reclaimed water irrigation. Emitter clogging is the bottleneck to restrain the application and popularization of reclaimed water drip irrigation technology, and some researchers have reported that this was tightly related to the formation of biofilms in the irrigation system. We selected reclaimed water treated with cyclic activated sludge system (CASS) and four kinds of labyrinth emitters in cusp-shaped saw-tooth, rectangular straight-tooth, arc-shaped saw-tooth and arc-angular straight-tooth and studied the surface topographical characteristics of biofilms in different positions of reclaimed water drip irrigation emitters with the 3D white-light scanning interferometer (WLSI). The results showed that biofilms in different positions of units were different with each emitter while showing the largest thickness in water-side tooth-tip zone ([20 lm); the biofilm thickness in the same monitoring sites inside one unit segment gradually decreased along the flow direction, while the flow at the inlets was much larger than that at the outlets; comparing the head, middle and tail parts, the biofilm thickness at the inlet and outlet showed the largest in the tail part, followed by the middle and the head parts. This can be explained by the equilibrium relation between hydrodynamic behavior and the transportation of nutrient and particles inside the emitters. The water-side tooth-tip zone of the first unit in the last emitter was selected to monitor surface topographical characteristics of biofilms, and its biofilm thickness also could be used as the indicator for evaluating the characteristics of surface topography. These results were aimed to provide references to explain the emitter clogging mechanism of reclaimed water drip irrigation as well as its technological application and popularization.

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Flow Characteristics in Energy Dissipation Units of Labyrinth Path in the Drip Irrigation Emitters with DPIV Technology

Cited by 32 publications

References 8 publications

Simulation of the flow characteristics of a drip irrigation emitter with large eddy methods

Simulation of the flow characteristics of a drip irrigation emitter with large eddy methods

Flow Characteristics and Pressure‐Compensating Mechanism of Non‐Pressure‐Compensating Drip Irrigation Emitters

Preliminary surface topographical characteristics of biofilms attached on drip irrigation emitters using reclaimed water

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