排灌机械工程学报2013，Vol.31Issue(4)：340-344,5.DOI:10.3969/j.issn.1674-8530.2013.04.013
滴头最大流量偏差率计算方法及影响因素评价
Calculation method of the maximum flow variation and evaluation of factors for micro-irrigation engineering
摘要
Abstract
The distribution characteristic of emitters' flow coefficient is analyzed.When flow coefficient complies with normal distribution,the probability of flow coefficient fluctuating at ± 3 times standard deviations is 99.73％ (approximating 100％).Thus,the minimum flow coefficient is average flow coefficient minus 3 times standard deviation and the maximum flow coefficient is average flow coefficient plus 3 times standard deviation.Based on the above analysis,a comprehensive flow variation rate calculation formula,taking hydraulic variation,manufacture variation and micro-terrain variation into consideration,is presented.Then,with emitter manufacturing variation coefficient,flow exponent,pressure difference and average field roughness height as influential factors,flow variation rate and lateral cost sensitivity were analyzed.The results show that emitter manufacturing variation coefficient is the most influential factor,followed by flow exponent and pressure difference.The lateral cost increases dramatically when manufacturing variation coefficient is larger than 0.04.In designing,emitters with minimal manufacture variation and minimal flow exponent should be elected.For normal drip irrigation systems,when the emitter's water-drop is larger than 10m,the effects of local height differences in fields on flow variation can be ignored.关键词
滴头/流量系数/流量偏差率/制造偏差系数/流态指数Key words
emitters / flow coefficient/ flow variation rate / emitter manufacturing variation coefficient/flow exponent分类
农业科技引用本文复制引用
朱德兰,吴普特,张林..滴头最大流量偏差率计算方法及影响因素评价[J].排灌机械工程学报,2013,31(4):340-344,5.基金项目
"十二五"国家科技支撑计划项目(2011BAD29B00) （2011BAD29B00）
教育部国家外国专家局"111"计划项目(B12007) （B12007）
