滴头插入对滴灌毛管水头损失影响试验研究  

Experimental study on effect of on-line emitter on head loss in drip irrigation laterals

作　　者：仇振杰[1] 朱德兰[1] 张林[1] 

机构地区：[1]西北农林科技大学中国旱区节水农业研究院,陕西杨凌712100

出　　处：《排灌机械工程学报》2013年第3期265-269,共5页Journal of Drainage and Irrigation Machinery Engineering

基　　金："十二五"国家科技支撑计划项目(2011BAD29B02)

摘　　要：为了提高滴灌毛管水力设计精度,通过试验研究了因滴头插入引起的毛管局部水头损失,根据试验现象分析了毛管局部水头损失占沿程水头损失比例hj/hf、毛管局部水头损失系数ξ,与滴头类型、滴头间距以及雷诺数之间的关系.结果表明:对于不同的滴头和滴头间距,毛管局部水头损失占沿程水头损失比例hj/hf差别较大.在相同间距下,迷宫流道滴头插入导致的hj/hf要大于压力补偿式滴头;对于同一类型滴头,滴头间距越小,局部水头损失越明显,hj/hf越大,且均大于微灌工程技术规范规定;若按规范取沿程水头损失的0.1～0.2计算局部水头损失,将导致滴灌工程设计中水头损失计算偏小.不同类型的滴头,毛管局部水头损失系数差异较大,其中迷宫流道滴头ξ基本在0.6以上,而压力补偿式滴头ξ为0.3～0.5,且ξ随滴头间距减小而增大、随雷诺数增大而减小,雷诺数越大,ξ变化越趋于平稳.通过对试验数据进行回归与统计分析,提出了毛管局部水头损失系数计算公式,相关系数R2为0.953.For hydraulic design of drip irrigation lateral to be improved, the minor head loss caused from on-line emitters in drip irrigation laterals was explored experimentally. Based on the experimental results, the minor head loss coefficient ξ and the ratio of the minor head loss over the frictional head loss, hj/hf, were correlated to Reynolds number and emitter spacing for different types of emitter. It was shown that hj/hf is considerably dependent on type of emitter and emitter spacing. At the same e- mitter spacing, hj/hf caused from on-line labyrinth channel emitters is greater than that from pressure compensating emitters; for the same type Of emitters, however, hj/hf is inversely proportional to emit- ter spacing. Importantly, all the hj/hf values are larger than those specified in the Technical Standard of Micro-Irrigation Project （SL - 103 - 95 ）. According to the standard, the minor head loss is about （0.1 - 0.2） % of the total frictional head loss ; obviously the total head loss will be underestimated by this. Further, the minor head loss coefficient ξ are related to the type of emitter, Reynolds number and emitter spacing. For labyrinth channel emitters the coefficient is higher than 0.6; however, for com- pensating pressure emitters, it is ranged in 0.3 -0.5. The coefficient increases with decreasing emitter spacing, and declines with increasing Reynolds number. An empirical formula for the coefficient wasproposed by regression.

关 键 词：滴灌 插入式滴头 局部水头损失 局部水头损失系数 沿程水头损失 

分 类 号：S275.6[农业科学—农业水土工程]