| 引用本文: | 李 杰,李俊龙,张以升.定常振荡流施肥模式对灌溉管道混合均匀性的影响[J].灌溉排水学报,2023,42(7):138-144. |
| LI Jie,LI Junlong,ZHANG Yisheng.定常振荡流施肥模式对灌溉管道混合均匀性的影响[J].灌溉排水学报,2023,42(7):138-144. |
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| 摘要: |
| 【目的】探究柱塞泵提供的定常振荡注肥模式对灌溉管网首部主干管道水肥混合均匀性的影响，寻求不同运行工况下分干管安全布设距离。【方法】采用室内试验与数值仿真相结合的方法，分析相同工况下管道内肥液质量分数，利用数值仿真方法探究温度、管径、主管流量以及注肥比对水肥混合均匀性影响。【结果】室内试验与数值仿真所得出的水肥混合均匀性规律吻合，随着混合距离的增加混合均匀性逐渐增大。其他工况相同时，当主管管径从63 mm增大到110 mm，有效混合距离平均增加了0.769 m；温度从10 ℃增加到30 ℃时，主管流量为6、8 m3/h处理的有效混合距离平均下降了0.499 m和1.681 mm；主管流量从6 m3/h增加到8 m3/h时，63、90、110 mm管径处理的有效混合距离平均增加了1.598、1.064、1.132 m；注肥比从2%增加到4%时，63、90、110 mm管径处理的有效混合距离平均减少了0.534、0.824、0.826 m。【结论】水肥混合均匀所需的有效混合距离随管径与主管流量的增加而增加，随温度与注肥比的增加而减少；采用63、90、110 mm的灌溉主管，分干管的开口位置应距注肥口5~5.5 m处。 |
| 关键词: 水肥一体化；数值模拟；多相流；注肥三通管；定常振荡流 |
| DOI：10.13522/j.cnki.ggps.2022582 |
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| Effects of Steady Intermittent Fertilizer Injection on Uniformity of Water and Fertilizer Mixture in Irrigation Pipe |
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LI Jie, LI Junlong, ZHANG Yisheng
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School of Water Conservancy and Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
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| Abstract: |
| 【Objective】 Intermittent fertilizer injection is commonly used in fertigation. The objective of this paper is to investigate the impact of steady intermittent fertilizer injection on the uniformity of water and fertilizer mixture within the head pipe in the irrigation network as well as the minimum safe distance for the branch pipes.【Method】Laboratory experiment was conducted to analyze the change in fertilizer concentration in the pipeline under ideal working conditions. The experimental results were used to validate a numerical model developed to simulate water flow and fertilizer movement in the pipe network. The validated numerical model was then used to evaluate the uniformity of water and fertilizer mixture in the pipe network under different conditions, including pipe diameter, water temperature, flow rates and fertilizer injection ratio. 【Result】The numerical model accurately reproduced the experimental results. The modelling results showed that when other conditions were constant, increasing the main pipe diameter from 63 mm to 110 mm increased the mixing distance by 0.769 m. Increasing the main flow rate from 6 m3/h to 8 m3/h increased the effective mixing distance by 1.598 m, 1.064 m, and 1.132 m for pipe diameters of 63 mm, 90 mm, and 110 mm, respectively. When the fertilizer injection ratio was increased from 2% to 4%, the effective mixing distance was reduced by 0.534 m, 0.824 m, and 0.826 m for pipe diameters of 63 mm, 90 mm, and 110 mm, respectively. It was also found that increasing the temperature from 10 ℃ to 30 ℃, the effective mixing distance of 6 m3/h and 8 m3/h decreased by 0.499 m and 1.681 mm on average.【Conclusion】The effective mixing distance required for uniformizing water and fertilizer in the irrigation pipe increases with the pipe diameter and flow rate, and decreases with the increase in temperature and fertilizer injection ratio. Pipe diameter and flow rate are the primary factors influencing the effective mixing distance. For main pipes with diameters of 63 mm, 90 mm, and 110 mm, the opening position for branch pipes should be 5~5.5 m away from the fertilizer injection pipe to ensure uniform mixture. |
| Key words: water and fertilizer integration; numerical simulation; multiphase flow; fertilizer injection tee pipe; steady oscillating flow |
