The Experts below are selected from a list of 9618 Experts worldwide ranked by ideXlab platform
Bo Zhou - One of the best experts on this subject based on the ideXlab platform.
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effects of phosphorus fertigation on emitter clogging in Drip Irrigation System with saline water
Agricultural Water Management, 2021Co-Authors: Tahir Muhammad, Bo Zhou, Zeyuan Liu, Xiuzhi ChenAbstract:Abstract Phosphorus (P) is an essential element for crop production. Drip Irrigation (DI) System, mainly because of its high precision, allows effective application of water-soluble P-fertilizers. However, consecutive input of P-fertilizer would react with ions in the water source, especially when using the saline water containing high concentration of ions. Consequently, the integration of P fertilizer and saline water results in more complicated and serious DI emitter clogging, which may damage the whole Irrigation System. Therefore, an in-situ field study was conducted to study the impacts of saline water concentrations (2 g L−1 and 4 g L-1) and water-soluble P-fertilizer types (urea phosphate, UP; and mono-potassium phosphate, MKP) on DI System performance. The results indicated that both UP and MKP application aggravated the emitter clogging process, and decreased the System discharge variation ratio (Dra) and Christiansen coefficient of uniformity (CU) by 2.62 %–11.7 % and 1.89 %–7.94 %, respectively. UP treatments performed better than MKP treatments in anti-clogging abilities, as it increased the DI System Dra (4.81 %–5.78 %) and CU (2.98 %–3.59 %). Besides, the impacts were significantly enhanced by higher water salinity. The System performance indicators were closely related to the chemical precipitations inside emitters, especially the relative contents and variations of the primary components (carbonates, quartz and silicates). UP performed better than MKP mainly because it lowered water pH and thus significantly reduced precipitation. Overall, clogging parameters (Dra and CU), clogging substances and the components of fertigation treatments all showed positive linear correlations with controlled treatments that without fertilizer applied (CK_2 and CK_4). The slopes of the fitting curves and significance analysis results combined demonstrated that, the water salinity had larger impact on emitter clogging process than fertilizer types. Present study offered references to fertilizer application using saline water to maintain Drip Irrigation System’s benefits.
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environmental risk of chlorine controlled clogging in Drip Irrigation System using reclaimed water the perspective of soil health
Journal of Cleaner Production, 2019Co-Authors: Peng Song, Bo Zhou, Hongxu Zhou, Gary Feng, John P Brooks, Zhirui ZhaoAbstract:Abstract Chemical chlorination is an effective method to control the emitter bio-clogging in Drip Irrigation using reclaimed water, but the broad spectrum of strong oxidative bactericidal action of chlorine causes certain risks to soil microbial communities and even soil health. Therefore, in this study, spring maize was selected as the research object, field chlorine experiments with Drip Irrigation using reclaimed water were carried out in two years, high-throughput sequencing technology combined with phospholipid fatty acids (PLFAs) technology was used, the biological bio-indicator of soil health (microbial community structure of soil) in the root zone of the spring maize were Systematically studied on the effects of different chlorination modes under the Drip Irrigation using reclaimed water. The effects of microbial community structure on soil enzyme activity and spring maize yield and quality were analyzed. The results showed that the total amount of PLFAs and bacteria content significantly decreased by 17.7 %–44.7 % and 7.0 %–47.3 %, which reduced the microbial community diversity. The relative abundance of Nitrospirae, Actinobacteria and Firmicutes decreased at the phylum level. The changes of microbial community structure reduced urease, catalase and phosphatase activities, inhibited the conversion and absorption of nutrients in the soil, which led to a decrease in crude fat and protein by 2.2 %–16.6 % and 2.2 %–14.1 %, respectively. But the yield of spring maize didn't significantly reduce. In comparison, long-term use of high concentration short duration chlorination mode was more likely to have adverse effects on soil health than low concentration long duration chlorination mode. The research results can provide a reference for the management of reclaimed water network Systems and soil health.
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Influence of operating pressure on emitter anti-clogging performance of Drip Irrigation System with high-sediment water
Agricultural Water Management, 2019Co-Authors: Yang Xiao, Yunkai Li, Ji Feng, Bo Zhou, Tahir MuhammadAbstract:Abstract Reducing emitters operating pressure has been widely acknowledged as one of the most effective approach to reduce Drip Irrigation System maintenance and operation costs. However, utilization of low-quality water, such as high-sediment water, reclaimed water, and brackish water, inevitably increases the emitters clogging risks. To examine the influence of different pressure levels on emitter clogging behavior and regulation path, an in-situ accelerated experiment of emitter clogging with high-sediment water was conducted with five operating pressure levels. The experiment was conducted from July 15, 2016, to October 15, 2016 with a total running time of 720 h. The results showed that emitter anti-clogging capability was gradually decreased as the operating pressure decreased below 100 to 60 kPa and was significant decreased as the operating pressure decreased below 60 to 40 kPa or lower. Therefore, the operating pressure should be kept above 60 kPa to maintain the favorable emitter anti-clogging performance. The change of the operating pressure directly and indirectly influenced the formation of clogging substance in the emitters. In addition, at different operating pressures, the anti-clogging performance parameters discharge ratio variation (Dra), coefficient of uniformity (CU), statistical uniformity coefficient (Us), emitter discharge variation (qvar), clogging substance within emitters (CSE) and clogging substance within laterals (CSL) were linearly correlated with anti-clogging performance parameters (Dra, CU, Us, qvar, CSE, CSL) of 100 kPa. Therefore, basing the Dra, CU, Us, qvar, CSE and CSL at 100 kPa, a simple linear model was established to predict anti-clogging performance parameters at the different pressures e.g. 20, 40, 60 and 80 kPa. This study could provide technical support for the application and promotion of the Drip Irrigation System with high-sediment water.
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formation mechanism for emitter composite clogging in Drip Irrigation System
Irrigation Science, 2019Co-Authors: Ji Feng, Tahir Muhammad, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Revealing the mechanism and influential path of emitter clogging in Drip Irrigation is the basis to control this issue. Eight commonly used flat emitters were tested to analyze the effects of emitter flow path geometric parameters on the hydraulic indexes, clogging performance, and composition of clogging substances, and the influential path was established through the path analysis method. The results indicated that the average cross-sectional velocity (v) was significantly correlated to clogging degrees and clogging substance formation. v directly affected the formation of clogging substance components, and was influenced by the width–depth ratio (W/D) and the relative radius (A1/2/L). Among all the components of the clogging substances, solid particle (SP), and CaCO3 and MgCO3 precipitates (C–MP) directly affected emitter clogging process, while phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) mainly relied on the indirect impacts. Therefore, emitter with larger v rather than that with larger Q should be a better choice from the perspective of the anti-clogging performance, and larger v could be obtained through the optimized design of emitter structure by controlling the appropriate ranges of W/D and A1/2/L.
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dynamic effects of chemical precipitates on Drip Irrigation System clogging using water with high sediment and salt loads
Agricultural Water Management, 2019Co-Authors: Jiachong Pan, Tahir Muhammad, Ji Feng, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Abstract Introducing low quality water to micro Irrigation System comes up with higher risk of emitter clogging and affects its practical applications in fields. Assessment of major components growth process of clogging substances and its influence on clogging to reveal the clogging mechanism become unavoidable. A Drip Irrigation experiment with four Irrigation and flushing treatments was conducted to study the chemical precipitates dynamic variations of chemical precipitates in clogging substances. 8 types of flat emitters subjected, and clogging samples were collected when emitter clogging degrees reached 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, respectively. X-ray diffractometer was applied to identify the mineral components. The results showed that both chemical and physical clogging occurred in all 4 operation modes and the primary chemical precipitates such as quartz and silicate (muscovite, alkali feldspar, chlorite and carbonate, dolomite, calcite) were found in emitter clogging substances. At the end of the experiment, their quantity accounted for more than 98%. Flushing treatment would slow down the accumulation of clogging substances in emitters. Although mixing these two water sources in same volume was equal to reduce the sediment and salinity concentrations to a half, the clogging degrees did not reduce as much as expected. On the other hand, positive linear correlations were observed between all three kinds of chemical precipitates and the clogging degrees, in which relative radius (A1/2/L) and mean velocity of flow path cross-section (v) showed significant impact, and thus affected the dynamic growth of chemical precipitates in clogging substances.
Tahir Muhammad - One of the best experts on this subject based on the ideXlab platform.
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effects of phosphorus fertigation on emitter clogging in Drip Irrigation System with saline water
Agricultural Water Management, 2021Co-Authors: Tahir Muhammad, Bo Zhou, Zeyuan Liu, Xiuzhi ChenAbstract:Abstract Phosphorus (P) is an essential element for crop production. Drip Irrigation (DI) System, mainly because of its high precision, allows effective application of water-soluble P-fertilizers. However, consecutive input of P-fertilizer would react with ions in the water source, especially when using the saline water containing high concentration of ions. Consequently, the integration of P fertilizer and saline water results in more complicated and serious DI emitter clogging, which may damage the whole Irrigation System. Therefore, an in-situ field study was conducted to study the impacts of saline water concentrations (2 g L−1 and 4 g L-1) and water-soluble P-fertilizer types (urea phosphate, UP; and mono-potassium phosphate, MKP) on DI System performance. The results indicated that both UP and MKP application aggravated the emitter clogging process, and decreased the System discharge variation ratio (Dra) and Christiansen coefficient of uniformity (CU) by 2.62 %–11.7 % and 1.89 %–7.94 %, respectively. UP treatments performed better than MKP treatments in anti-clogging abilities, as it increased the DI System Dra (4.81 %–5.78 %) and CU (2.98 %–3.59 %). Besides, the impacts were significantly enhanced by higher water salinity. The System performance indicators were closely related to the chemical precipitations inside emitters, especially the relative contents and variations of the primary components (carbonates, quartz and silicates). UP performed better than MKP mainly because it lowered water pH and thus significantly reduced precipitation. Overall, clogging parameters (Dra and CU), clogging substances and the components of fertigation treatments all showed positive linear correlations with controlled treatments that without fertilizer applied (CK_2 and CK_4). The slopes of the fitting curves and significance analysis results combined demonstrated that, the water salinity had larger impact on emitter clogging process than fertilizer types. Present study offered references to fertilizer application using saline water to maintain Drip Irrigation System’s benefits.
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mechanism of intermittent fluctuated water pressure on emitter clogging substances formation in Drip Irrigation System utilizing high sediment water
Agricultural Water Management, 2019Co-Authors: Peng Song, Tahir Muhammad, Yang Xiao, Zeyuan Liu, Hongxu ZhouAbstract:Abstract Emitter clogging is one of the bottlenecks that restricts the application and promotion of Drip Irrigation technology. Applying intermittent fluctuated water pressure is regarded as an effective way to overcome Drip Irrigation emitter clogging when using high sediment water. Therefore, a Drip Irrigation experiment using Yellow River water was carried out at Deng Kou County, Inner Mongolia, China, to study emitter clogging controlling effects of three fluctuation patterns. The control group (CG) operation pressure was 40 kPa, and three intermittent fluctuated water pressure modes were 40 kPa + fluctuating water pressure for 1 h (FP1 h), 2 h (FP2 h), and 4 h (FP4 h), respectively. The System was fluctuated once every 16 h, and the amplitude of the fluctuating water pressure was 80–100 kPa with a cycle of 40 s. The characteristics of the sediment size and mineral components of clogging substances found in emitters and laterals were also analyzed. The results showed that intermittent fluctuated water pressure not only directly changed the flow velocity distribution in the emitter flow path to reduce the deposition of clogging substances, but also controlled the formation of clogging substances inside the laterals to avoid enhanced emitter clogging by transporting into the emitter. The intermittent fluctuated operating pressure could effectively reduce contents of emitter clogging substance in Drip Irrigation, and the longer period it was applied, the better controlling effect was observed. Comparing with the CG, applying intermittent fluctuated water pressure with constant period of 4 h would reduce the total clogging substance contents by 26%. The clay and powder particles were reduced by 56% and 34%, respectively. Meanwhile the quartz, silicate, calcium magnesium and carbonate in the clogging substances decreased by 36%, 35%, and 11%, respectively. Thus, the discharge ratio variation coefficient (Dra) and Christiansen Uniformity coefficient (CU) increased by 10.1–16.7% and 8.9–14.2%, correspondingly. These results could provide references for the application and promotion of Drip Irrigation technology using water with high sediment load.
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Influence of operating pressure on emitter anti-clogging performance of Drip Irrigation System with high-sediment water
Agricultural Water Management, 2019Co-Authors: Yang Xiao, Yunkai Li, Ji Feng, Bo Zhou, Tahir MuhammadAbstract:Abstract Reducing emitters operating pressure has been widely acknowledged as one of the most effective approach to reduce Drip Irrigation System maintenance and operation costs. However, utilization of low-quality water, such as high-sediment water, reclaimed water, and brackish water, inevitably increases the emitters clogging risks. To examine the influence of different pressure levels on emitter clogging behavior and regulation path, an in-situ accelerated experiment of emitter clogging with high-sediment water was conducted with five operating pressure levels. The experiment was conducted from July 15, 2016, to October 15, 2016 with a total running time of 720 h. The results showed that emitter anti-clogging capability was gradually decreased as the operating pressure decreased below 100 to 60 kPa and was significant decreased as the operating pressure decreased below 60 to 40 kPa or lower. Therefore, the operating pressure should be kept above 60 kPa to maintain the favorable emitter anti-clogging performance. The change of the operating pressure directly and indirectly influenced the formation of clogging substance in the emitters. In addition, at different operating pressures, the anti-clogging performance parameters discharge ratio variation (Dra), coefficient of uniformity (CU), statistical uniformity coefficient (Us), emitter discharge variation (qvar), clogging substance within emitters (CSE) and clogging substance within laterals (CSL) were linearly correlated with anti-clogging performance parameters (Dra, CU, Us, qvar, CSE, CSL) of 100 kPa. Therefore, basing the Dra, CU, Us, qvar, CSE and CSL at 100 kPa, a simple linear model was established to predict anti-clogging performance parameters at the different pressures e.g. 20, 40, 60 and 80 kPa. This study could provide technical support for the application and promotion of the Drip Irrigation System with high-sediment water.
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formation mechanism for emitter composite clogging in Drip Irrigation System
Irrigation Science, 2019Co-Authors: Ji Feng, Tahir Muhammad, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Revealing the mechanism and influential path of emitter clogging in Drip Irrigation is the basis to control this issue. Eight commonly used flat emitters were tested to analyze the effects of emitter flow path geometric parameters on the hydraulic indexes, clogging performance, and composition of clogging substances, and the influential path was established through the path analysis method. The results indicated that the average cross-sectional velocity (v) was significantly correlated to clogging degrees and clogging substance formation. v directly affected the formation of clogging substance components, and was influenced by the width–depth ratio (W/D) and the relative radius (A1/2/L). Among all the components of the clogging substances, solid particle (SP), and CaCO3 and MgCO3 precipitates (C–MP) directly affected emitter clogging process, while phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) mainly relied on the indirect impacts. Therefore, emitter with larger v rather than that with larger Q should be a better choice from the perspective of the anti-clogging performance, and larger v could be obtained through the optimized design of emitter structure by controlling the appropriate ranges of W/D and A1/2/L.
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dynamic effects of chemical precipitates on Drip Irrigation System clogging using water with high sediment and salt loads
Agricultural Water Management, 2019Co-Authors: Jiachong Pan, Tahir Muhammad, Ji Feng, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Abstract Introducing low quality water to micro Irrigation System comes up with higher risk of emitter clogging and affects its practical applications in fields. Assessment of major components growth process of clogging substances and its influence on clogging to reveal the clogging mechanism become unavoidable. A Drip Irrigation experiment with four Irrigation and flushing treatments was conducted to study the chemical precipitates dynamic variations of chemical precipitates in clogging substances. 8 types of flat emitters subjected, and clogging samples were collected when emitter clogging degrees reached 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, respectively. X-ray diffractometer was applied to identify the mineral components. The results showed that both chemical and physical clogging occurred in all 4 operation modes and the primary chemical precipitates such as quartz and silicate (muscovite, alkali feldspar, chlorite and carbonate, dolomite, calcite) were found in emitter clogging substances. At the end of the experiment, their quantity accounted for more than 98%. Flushing treatment would slow down the accumulation of clogging substances in emitters. Although mixing these two water sources in same volume was equal to reduce the sediment and salinity concentrations to a half, the clogging degrees did not reduce as much as expected. On the other hand, positive linear correlations were observed between all three kinds of chemical precipitates and the clogging degrees, in which relative radius (A1/2/L) and mean velocity of flow path cross-section (v) showed significant impact, and thus affected the dynamic growth of chemical precipitates in clogging substances.
Ji Feng - One of the best experts on this subject based on the ideXlab platform.
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Influence of operating pressure on emitter anti-clogging performance of Drip Irrigation System with high-sediment water
Agricultural Water Management, 2019Co-Authors: Yang Xiao, Yunkai Li, Ji Feng, Bo Zhou, Tahir MuhammadAbstract:Abstract Reducing emitters operating pressure has been widely acknowledged as one of the most effective approach to reduce Drip Irrigation System maintenance and operation costs. However, utilization of low-quality water, such as high-sediment water, reclaimed water, and brackish water, inevitably increases the emitters clogging risks. To examine the influence of different pressure levels on emitter clogging behavior and regulation path, an in-situ accelerated experiment of emitter clogging with high-sediment water was conducted with five operating pressure levels. The experiment was conducted from July 15, 2016, to October 15, 2016 with a total running time of 720 h. The results showed that emitter anti-clogging capability was gradually decreased as the operating pressure decreased below 100 to 60 kPa and was significant decreased as the operating pressure decreased below 60 to 40 kPa or lower. Therefore, the operating pressure should be kept above 60 kPa to maintain the favorable emitter anti-clogging performance. The change of the operating pressure directly and indirectly influenced the formation of clogging substance in the emitters. In addition, at different operating pressures, the anti-clogging performance parameters discharge ratio variation (Dra), coefficient of uniformity (CU), statistical uniformity coefficient (Us), emitter discharge variation (qvar), clogging substance within emitters (CSE) and clogging substance within laterals (CSL) were linearly correlated with anti-clogging performance parameters (Dra, CU, Us, qvar, CSE, CSL) of 100 kPa. Therefore, basing the Dra, CU, Us, qvar, CSE and CSL at 100 kPa, a simple linear model was established to predict anti-clogging performance parameters at the different pressures e.g. 20, 40, 60 and 80 kPa. This study could provide technical support for the application and promotion of the Drip Irrigation System with high-sediment water.
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formation mechanism for emitter composite clogging in Drip Irrigation System
Irrigation Science, 2019Co-Authors: Ji Feng, Tahir Muhammad, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Revealing the mechanism and influential path of emitter clogging in Drip Irrigation is the basis to control this issue. Eight commonly used flat emitters were tested to analyze the effects of emitter flow path geometric parameters on the hydraulic indexes, clogging performance, and composition of clogging substances, and the influential path was established through the path analysis method. The results indicated that the average cross-sectional velocity (v) was significantly correlated to clogging degrees and clogging substance formation. v directly affected the formation of clogging substance components, and was influenced by the width–depth ratio (W/D) and the relative radius (A1/2/L). Among all the components of the clogging substances, solid particle (SP), and CaCO3 and MgCO3 precipitates (C–MP) directly affected emitter clogging process, while phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) mainly relied on the indirect impacts. Therefore, emitter with larger v rather than that with larger Q should be a better choice from the perspective of the anti-clogging performance, and larger v could be obtained through the optimized design of emitter structure by controlling the appropriate ranges of W/D and A1/2/L.
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dynamic effects of chemical precipitates on Drip Irrigation System clogging using water with high sediment and salt loads
Agricultural Water Management, 2019Co-Authors: Jiachong Pan, Tahir Muhammad, Ji Feng, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Abstract Introducing low quality water to micro Irrigation System comes up with higher risk of emitter clogging and affects its practical applications in fields. Assessment of major components growth process of clogging substances and its influence on clogging to reveal the clogging mechanism become unavoidable. A Drip Irrigation experiment with four Irrigation and flushing treatments was conducted to study the chemical precipitates dynamic variations of chemical precipitates in clogging substances. 8 types of flat emitters subjected, and clogging samples were collected when emitter clogging degrees reached 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, respectively. X-ray diffractometer was applied to identify the mineral components. The results showed that both chemical and physical clogging occurred in all 4 operation modes and the primary chemical precipitates such as quartz and silicate (muscovite, alkali feldspar, chlorite and carbonate, dolomite, calcite) were found in emitter clogging substances. At the end of the experiment, their quantity accounted for more than 98%. Flushing treatment would slow down the accumulation of clogging substances in emitters. Although mixing these two water sources in same volume was equal to reduce the sediment and salinity concentrations to a half, the clogging degrees did not reduce as much as expected. On the other hand, positive linear correlations were observed between all three kinds of chemical precipitates and the clogging degrees, in which relative radius (A1/2/L) and mean velocity of flow path cross-section (v) showed significant impact, and thus affected the dynamic growth of chemical precipitates in clogging substances.
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effect of optimization forms of flow path on emitter hydraulic and anti clogging performance in Drip Irrigation System
Irrigation Science, 2018Co-Authors: Ji Feng, Weinan Wang, Song XueAbstract:This study aims to solve the problem of emitter clogging by optimizing the flow path boundary and making it self-cleaning, thereby reducing cost of Drip Irrigation project to promote water-saving Irrigation technologies. To resolve the question of whether the emitter optimizations should retain the vortex area with low velocity, which are the two main optimization ideas currently, we used computational fluid dynamics (CFD) analysis to evaluate the most commonly used emitter, one with a tooth-type labyrinth flow path. A re-normalization group (RNG) k–e turbulence model was used to evaluate two types of main channel anti-clogging designs, whose vortex was retained, and three types of washing walls—all types that use a vortex. The result of the flow state analysis showed that, as for the hydraulic performance, the flow state indexes of flow paths optimized by two types of design method were up to 5% lower than that of prototype’s flow path. Flow coefficients of the flow path optimized using the main channel design method were 4–6 times higher than that of the prototype’s flow path, which could significantly increase the construction cost of emitter and Drip Irrigation System. However, the flow coefficients of flow path optimized by design method of washing wall with vortex were up to 3% lower than the prototype’s flow path; thus, their effect on the emitter’s hydraulic performance can be ignored. As for the anti-clogging performance, there was nearly no vortex area formed in the flow path optimized by the main channel design method, and the sediment could flow out easily from the emitter. However, the emitter’s ability to resist biological and chemical clogging was weak, because the sediment content was highest in the tooth-tip facing-water zone where the sediments deposit easily. The overall intensity of turbulence was lower than that of the prototype, and the velocity near the wall was lower than in other optimized forms. The design method of washing wall with vortex could make the vortex fully develop in the flow path, and enhance the velocity near wall and turbulent intensity in the area where sediment deposited easily. The cycle motion of vortex could wash the wall, which could keep the viscous clogging material from attaching the wall and promote their detachment. The emitter’s self-cleaning ability was also enhanced. Overall, the flow path optimized by design method of washing wall with vortex could enhance synergistically hydraulic and anti-clogging performance in the easiest and most cost-effective way. As for the tooth labyrinth flow path, the best boundary optimization form was that the tooth-tip backing-water zone, tooth-tip facing-water zone, tooth-root backing-water zone and tooth-root facing-water zone were optimized by the same arc whose radius was equal to 1/2 width of the flow path. This study could provide theoretical reference for emitter structural design.
Song Xue - One of the best experts on this subject based on the ideXlab platform.
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dynamic effects of chemical precipitates on Drip Irrigation System clogging using water with high sediment and salt loads
Agricultural Water Management, 2019Co-Authors: Jiachong Pan, Tahir Muhammad, Ji Feng, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Abstract Introducing low quality water to micro Irrigation System comes up with higher risk of emitter clogging and affects its practical applications in fields. Assessment of major components growth process of clogging substances and its influence on clogging to reveal the clogging mechanism become unavoidable. A Drip Irrigation experiment with four Irrigation and flushing treatments was conducted to study the chemical precipitates dynamic variations of chemical precipitates in clogging substances. 8 types of flat emitters subjected, and clogging samples were collected when emitter clogging degrees reached 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, respectively. X-ray diffractometer was applied to identify the mineral components. The results showed that both chemical and physical clogging occurred in all 4 operation modes and the primary chemical precipitates such as quartz and silicate (muscovite, alkali feldspar, chlorite and carbonate, dolomite, calcite) were found in emitter clogging substances. At the end of the experiment, their quantity accounted for more than 98%. Flushing treatment would slow down the accumulation of clogging substances in emitters. Although mixing these two water sources in same volume was equal to reduce the sediment and salinity concentrations to a half, the clogging degrees did not reduce as much as expected. On the other hand, positive linear correlations were observed between all three kinds of chemical precipitates and the clogging degrees, in which relative radius (A1/2/L) and mean velocity of flow path cross-section (v) showed significant impact, and thus affected the dynamic growth of chemical precipitates in clogging substances.
-
formation mechanism for emitter composite clogging in Drip Irrigation System
Irrigation Science, 2019Co-Authors: Ji Feng, Tahir Muhammad, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Revealing the mechanism and influential path of emitter clogging in Drip Irrigation is the basis to control this issue. Eight commonly used flat emitters were tested to analyze the effects of emitter flow path geometric parameters on the hydraulic indexes, clogging performance, and composition of clogging substances, and the influential path was established through the path analysis method. The results indicated that the average cross-sectional velocity (v) was significantly correlated to clogging degrees and clogging substance formation. v directly affected the formation of clogging substance components, and was influenced by the width–depth ratio (W/D) and the relative radius (A1/2/L). Among all the components of the clogging substances, solid particle (SP), and CaCO3 and MgCO3 precipitates (C–MP) directly affected emitter clogging process, while phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) mainly relied on the indirect impacts. Therefore, emitter with larger v rather than that with larger Q should be a better choice from the perspective of the anti-clogging performance, and larger v could be obtained through the optimized design of emitter structure by controlling the appropriate ranges of W/D and A1/2/L.
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effect of optimization forms of flow path on emitter hydraulic and anti clogging performance in Drip Irrigation System
Irrigation Science, 2018Co-Authors: Ji Feng, Weinan Wang, Song XueAbstract:This study aims to solve the problem of emitter clogging by optimizing the flow path boundary and making it self-cleaning, thereby reducing cost of Drip Irrigation project to promote water-saving Irrigation technologies. To resolve the question of whether the emitter optimizations should retain the vortex area with low velocity, which are the two main optimization ideas currently, we used computational fluid dynamics (CFD) analysis to evaluate the most commonly used emitter, one with a tooth-type labyrinth flow path. A re-normalization group (RNG) k–e turbulence model was used to evaluate two types of main channel anti-clogging designs, whose vortex was retained, and three types of washing walls—all types that use a vortex. The result of the flow state analysis showed that, as for the hydraulic performance, the flow state indexes of flow paths optimized by two types of design method were up to 5% lower than that of prototype’s flow path. Flow coefficients of the flow path optimized using the main channel design method were 4–6 times higher than that of the prototype’s flow path, which could significantly increase the construction cost of emitter and Drip Irrigation System. However, the flow coefficients of flow path optimized by design method of washing wall with vortex were up to 3% lower than the prototype’s flow path; thus, their effect on the emitter’s hydraulic performance can be ignored. As for the anti-clogging performance, there was nearly no vortex area formed in the flow path optimized by the main channel design method, and the sediment could flow out easily from the emitter. However, the emitter’s ability to resist biological and chemical clogging was weak, because the sediment content was highest in the tooth-tip facing-water zone where the sediments deposit easily. The overall intensity of turbulence was lower than that of the prototype, and the velocity near the wall was lower than in other optimized forms. The design method of washing wall with vortex could make the vortex fully develop in the flow path, and enhance the velocity near wall and turbulent intensity in the area where sediment deposited easily. The cycle motion of vortex could wash the wall, which could keep the viscous clogging material from attaching the wall and promote their detachment. The emitter’s self-cleaning ability was also enhanced. Overall, the flow path optimized by design method of washing wall with vortex could enhance synergistically hydraulic and anti-clogging performance in the easiest and most cost-effective way. As for the tooth labyrinth flow path, the best boundary optimization form was that the tooth-tip backing-water zone, tooth-tip facing-water zone, tooth-root backing-water zone and tooth-root facing-water zone were optimized by the same arc whose radius was equal to 1/2 width of the flow path. This study could provide theoretical reference for emitter structural design.
Xiuzhi Chen - One of the best experts on this subject based on the ideXlab platform.
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effects of phosphorus fertigation on emitter clogging in Drip Irrigation System with saline water
Agricultural Water Management, 2021Co-Authors: Tahir Muhammad, Bo Zhou, Zeyuan Liu, Xiuzhi ChenAbstract:Abstract Phosphorus (P) is an essential element for crop production. Drip Irrigation (DI) System, mainly because of its high precision, allows effective application of water-soluble P-fertilizers. However, consecutive input of P-fertilizer would react with ions in the water source, especially when using the saline water containing high concentration of ions. Consequently, the integration of P fertilizer and saline water results in more complicated and serious DI emitter clogging, which may damage the whole Irrigation System. Therefore, an in-situ field study was conducted to study the impacts of saline water concentrations (2 g L−1 and 4 g L-1) and water-soluble P-fertilizer types (urea phosphate, UP; and mono-potassium phosphate, MKP) on DI System performance. The results indicated that both UP and MKP application aggravated the emitter clogging process, and decreased the System discharge variation ratio (Dra) and Christiansen coefficient of uniformity (CU) by 2.62 %–11.7 % and 1.89 %–7.94 %, respectively. UP treatments performed better than MKP treatments in anti-clogging abilities, as it increased the DI System Dra (4.81 %–5.78 %) and CU (2.98 %–3.59 %). Besides, the impacts were significantly enhanced by higher water salinity. The System performance indicators were closely related to the chemical precipitations inside emitters, especially the relative contents and variations of the primary components (carbonates, quartz and silicates). UP performed better than MKP mainly because it lowered water pH and thus significantly reduced precipitation. Overall, clogging parameters (Dra and CU), clogging substances and the components of fertigation treatments all showed positive linear correlations with controlled treatments that without fertilizer applied (CK_2 and CK_4). The slopes of the fitting curves and significance analysis results combined demonstrated that, the water salinity had larger impact on emitter clogging process than fertilizer types. Present study offered references to fertilizer application using saline water to maintain Drip Irrigation System’s benefits.
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formation mechanism for emitter composite clogging in Drip Irrigation System
Irrigation Science, 2019Co-Authors: Ji Feng, Tahir Muhammad, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Revealing the mechanism and influential path of emitter clogging in Drip Irrigation is the basis to control this issue. Eight commonly used flat emitters were tested to analyze the effects of emitter flow path geometric parameters on the hydraulic indexes, clogging performance, and composition of clogging substances, and the influential path was established through the path analysis method. The results indicated that the average cross-sectional velocity (v) was significantly correlated to clogging degrees and clogging substance formation. v directly affected the formation of clogging substance components, and was influenced by the width–depth ratio (W/D) and the relative radius (A1/2/L). Among all the components of the clogging substances, solid particle (SP), and CaCO3 and MgCO3 precipitates (C–MP) directly affected emitter clogging process, while phospholipid fatty acids (PLFAs) and extracellular polymeric substance (EPS) mainly relied on the indirect impacts. Therefore, emitter with larger v rather than that with larger Q should be a better choice from the perspective of the anti-clogging performance, and larger v could be obtained through the optimized design of emitter structure by controlling the appropriate ranges of W/D and A1/2/L.
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dynamic effects of chemical precipitates on Drip Irrigation System clogging using water with high sediment and salt loads
Agricultural Water Management, 2019Co-Authors: Jiachong Pan, Tahir Muhammad, Ji Feng, Bo Zhou, Song Xue, Xiuzhi ChenAbstract:Abstract Introducing low quality water to micro Irrigation System comes up with higher risk of emitter clogging and affects its practical applications in fields. Assessment of major components growth process of clogging substances and its influence on clogging to reveal the clogging mechanism become unavoidable. A Drip Irrigation experiment with four Irrigation and flushing treatments was conducted to study the chemical precipitates dynamic variations of chemical precipitates in clogging substances. 8 types of flat emitters subjected, and clogging samples were collected when emitter clogging degrees reached 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, respectively. X-ray diffractometer was applied to identify the mineral components. The results showed that both chemical and physical clogging occurred in all 4 operation modes and the primary chemical precipitates such as quartz and silicate (muscovite, alkali feldspar, chlorite and carbonate, dolomite, calcite) were found in emitter clogging substances. At the end of the experiment, their quantity accounted for more than 98%. Flushing treatment would slow down the accumulation of clogging substances in emitters. Although mixing these two water sources in same volume was equal to reduce the sediment and salinity concentrations to a half, the clogging degrees did not reduce as much as expected. On the other hand, positive linear correlations were observed between all three kinds of chemical precipitates and the clogging degrees, in which relative radius (A1/2/L) and mean velocity of flow path cross-section (v) showed significant impact, and thus affected the dynamic growth of chemical precipitates in clogging substances.
