[Objectives] By reasonable water distribution and air supply to soil, soil water permeability is maintained, and the nutrient conditions of degrading bacteria in soil are improved to effectively prevent soil clogging....[Objectives] By reasonable water distribution and air supply to soil, soil water permeability is maintained, and the nutrient conditions of degrading bacteria in soil are improved to effectively prevent soil clogging. [Methods] Through the innovation and improvement of traditional soil sewage treatment technology, the physical, chemical and biological characteristics of soil for sewage purification are utilized to enhance the pollutant decomposition ability of soil microorganisms and maintain soil water permeability.[Results] It has no secondary pollution, and can effectively remove pollutants such as COD_(Cr), TN, TP, NH_3-N, etc. in sewage. [Conclusions] The operation and maintenance cost is low, and the land can be reused, while water and nutrients can be restored to the land.展开更多
<div style="text-align:justify;"> Due to the poor anti-clogging performance of the common drip irrigation emitters, this paper designed a new bionic flow channel in the emitter based on the shape of sh...<div style="text-align:justify;"> Due to the poor anti-clogging performance of the common drip irrigation emitters, this paper designed a new bionic flow channel in the emitter based on the shape of shark dorsal fin. After preliminary structural design, the computational fluid dynamics (CFD) simulation showed that the bionic emitter exhibited superior anti-clogging performance and reasonable hydraulic performance. The passage rate of particles of the bionic emitter in simulation reached 96.3% which was 37.6% higher than 70% of traditional emitter, and the discharge exponent reached 0.4995 which was close to traditional emitter. Physical experiments were consistent with the CFD results, which confirmed the correctness of simulation. After a short cycle anti-clogging performance experiment, the bionic emitter still maintained 96.09% of the initial flow rate. </div>展开更多
Emitter clogging is one of the most serious factors that restrict the drip irrigation system operation and water use efficiency.To scientifically characterize and evaluate emitter clogging risk,a literature review,sho...Emitter clogging is one of the most serious factors that restrict the drip irrigation system operation and water use efficiency.To scientifically characterize and evaluate emitter clogging risk,a literature review,short-period emitter anti-clogging tests,and CFD(Computational Fluid Dynamics)hydraulic performance tests were conducted.Results showed that the emitter anti-clogging ability is related to its structure,material,and processing technology,not external factors.This was evidenced in the irrigation tests,as with the different water qualities,the same emitters were repeatedly prone to clog or to avoid clogging.A predictive model of structural resistance coefficient(Cs),a quantitative indicator of the emitter anti-clogging ability,whose value ranges between 0 and 1,was utilized.Larger Cs values indicate a lower anti-clogging ability and thus a higher risk of clogging.A good linear relationship between Cs and the relative flow rate was detected,and the Cs relationship with the fluidity index(x)was determined to be a power function.The Cs should be controlled within the range of 0.146-0.461 when designing new emitters to ensure that they have good anti-clogging properties.This research will provide theoretical guidance for the anti-clogging management of drip irrigation systems and for the design of optimal emitter structures.展开更多
文摘[Objectives] By reasonable water distribution and air supply to soil, soil water permeability is maintained, and the nutrient conditions of degrading bacteria in soil are improved to effectively prevent soil clogging. [Methods] Through the innovation and improvement of traditional soil sewage treatment technology, the physical, chemical and biological characteristics of soil for sewage purification are utilized to enhance the pollutant decomposition ability of soil microorganisms and maintain soil water permeability.[Results] It has no secondary pollution, and can effectively remove pollutants such as COD_(Cr), TN, TP, NH_3-N, etc. in sewage. [Conclusions] The operation and maintenance cost is low, and the land can be reused, while water and nutrients can be restored to the land.
文摘<div style="text-align:justify;"> Due to the poor anti-clogging performance of the common drip irrigation emitters, this paper designed a new bionic flow channel in the emitter based on the shape of shark dorsal fin. After preliminary structural design, the computational fluid dynamics (CFD) simulation showed that the bionic emitter exhibited superior anti-clogging performance and reasonable hydraulic performance. The passage rate of particles of the bionic emitter in simulation reached 96.3% which was 37.6% higher than 70% of traditional emitter, and the discharge exponent reached 0.4995 which was close to traditional emitter. Physical experiments were consistent with the CFD results, which confirmed the correctness of simulation. After a short cycle anti-clogging performance experiment, the bionic emitter still maintained 96.09% of the initial flow rate. </div>
基金supported by the National Key Research and Development Plan of China(Grant No.2016YFC0400202)Shandong province major innovation project(2020CXGC010808),and the National Natural Science Fund of China(Grant No.51679205,52079112).
文摘Emitter clogging is one of the most serious factors that restrict the drip irrigation system operation and water use efficiency.To scientifically characterize and evaluate emitter clogging risk,a literature review,short-period emitter anti-clogging tests,and CFD(Computational Fluid Dynamics)hydraulic performance tests were conducted.Results showed that the emitter anti-clogging ability is related to its structure,material,and processing technology,not external factors.This was evidenced in the irrigation tests,as with the different water qualities,the same emitters were repeatedly prone to clog or to avoid clogging.A predictive model of structural resistance coefficient(Cs),a quantitative indicator of the emitter anti-clogging ability,whose value ranges between 0 and 1,was utilized.Larger Cs values indicate a lower anti-clogging ability and thus a higher risk of clogging.A good linear relationship between Cs and the relative flow rate was detected,and the Cs relationship with the fluidity index(x)was determined to be a power function.The Cs should be controlled within the range of 0.146-0.461 when designing new emitters to ensure that they have good anti-clogging properties.This research will provide theoretical guidance for the anti-clogging management of drip irrigation systems and for the design of optimal emitter structures.
