地下滴灌灌水器负压吸泥影响因素试验研究

为了探究引起地下滴灌系统灌水器负压吸泥的影响因素,通过对比试验,研究分析了土壤类型、单次灌水量、灌溉次数、灌水器类型、保水剂和灌水间隔等6个因素对灌水器负压吸泥的影响规律。结果表明,1流量可调式灌水器出水孔外部及内部存在负压吸泥并引起堵塞情况。外部出水孔有3个被堵塞的所占比例最多,为26.7%;泥沙分布主要集中在灌水器出水孔的内侧附近,有极少部分泥沙甚至可以越过内凸边缘,进入灌水器内圈。2压力补偿式灌水器抗负压吸泥的能力强于流量可调式灌水器,压力补偿式灌水器外部出水口及内部未发现有泥沙,而流量可调式灌水器外部出水口及内部有泥沙;灌水器在红壤土中比黄沙土中更容易出现负压吸泥情况,灌水器在红壤土中的内部泥沙量是黄沙土中的1.12~1.76倍。3灌溉方式(单次灌水量、灌溉次数、灌水间隔)对灌水器负压吸泥的影响显著。单次灌水量小的灌水器内部泥沙量较多,灌水器单次灌水量为170 m L内部泥沙量是250 m L的1.61~2.94倍;灌溉次数与负压吸泥量成正比,灌溉次数为16次的内部泥沙量是8次的3.48~5.41倍;在同一灌溉次数的条件下,灌水间隔长度与负压吸泥量成正比。4保水剂能够有效阻隔泥沙进入灌水器内部,在添加了保水剂的灌水器中,其内部未出现负压吸泥的现象。

Influencing Factors of Negative Pressure Suction for Mud in Subsurface Drip Irrigation Emitter

In order to explore the influencing factors of negative pressure suction for mud of emitter under the SDI system,the influencing laws of the 6 factors,includory soil type,single irrigation amount,irrigation times,emitter type,water retaining agent and irrigation interval,were studied by contrast test.The results indicated that,①negative pressure suction for mud and blocking condition were in existence both in the external and internal of water outlet of adjustable flow emitter.Three external water outlets were blocked with the largest ratio of 26.7％.The sediment distribution was mainly concentrated in the vicinity of the medial emitter outlets;very little part of the sediment even crossed the inner convex edge into the inner ring of the emitter.②The ability of resisting negative pressure suction for mud of emitter in pressure compensating emitter was stronger than that of the flow adjustable emitter.No sediment was found in the external and internal water outlets of pressure compensating emitters,while some sediment was found in the external and internal water outlets of adjustable flow emitters.The negative pressure suction for mud was more prone to red soil than sand soil.The amount of internal sediment of emitter in red soil were 1.12～ 1.76 times than that of the amount in sand soil.③The effect of irrigation methods (the amount of single irrigation,irrigation times,and irrigation interval) on negative pressure suction for mud of emitter was significant.The emitters with small internal single irrigation amount had a bigger amount of sediment.The amount of internal sediment in 170 mL single irrigation were 1.61 ～2.94 times than the amount in 250 mL.Irrigation times were directly proportional to the amount of negative pressure for mud.The amount of internal sediment for the 16 times of irrigation were 3.48～5.41 times than the amount in 8 times.Under the condition of the same irrigation times,the length of irrigation interval was directly proportional to the amount of negative pressure for mud.④There was no negative pressure sucking mud in the emitter with water retaining agent.This paper provides a theoretical basis for the development of the irrigation device with the performance of good antinegative-pressure-suction for mud of emitter.