| 基于流量偏差率的滴灌毛管管径简易设计 |
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| 引用本文： | 鞠学良,吴普特,Weckler R. Paul,朱德兰,张林.基于流量偏差率的滴灌毛管管径简易设计[J].农业工程学报,2016,32(5):14-20. |
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| 作者姓名： | 鞠学良 吴普特 Weckler R. Paul 朱德兰 张林 |
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| 作者单位： | 1. 西北农林科技大学水土保持研究所，杨凌712100; 西北农林科技大学中国旱区节水农业研究院，杨凌 712100;2. 西北农林科技大学中国旱区节水农业研究院,杨凌,712100;3. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100,China |
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| 基金项目： | National Key Technology Research and Development Program of the Ministry of Science and Technology of China (2015BAD22B01-02); National International Cooperation in Science and Technology Special Program (2014DFG72150); 111 Project (B12007) |
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| 摘 要： | 满足灌水均匀度设计标准与额定流量的滴灌毛管管径优化设计是滴灌毛管水力设计的重要内容。该文以流量偏差率为灌水均匀度设计标准，提出一种简易的滴灌毛管管径水力设计方法。通过改变单向和双向滴灌毛管流量偏差率解析公式的形式，提出一个新的管径设计参数。基于能坡线法，建立参数与坡降比参数的关系，并绘制和构建相关图形和计算公式。结果表明：当流量指数分别取值为1.75、1.69和1.00时，单向毛管管径的设计参数取值分别为?1～≤2.801，?1～≤2.859和?1～≤4；双向毛管管径的设计参数取值分别为0～≤3.143，0～≤3.183和0～≤4。满足流量偏差率设计标准和灌水器额定流量时，单向毛管管径将有1或2个设计值，双向毛管管径将有1、2或多个设计值。根据参数的取值范围，以坡降比参数为设计变量，推导了均匀坡下单向和双向毛管管径的计算公式。此外，进一步简化了滴灌毛管进口工作水头的计算公式。当已知设计流量，流量偏差率设计标准，毛管管长等参数时，可以按照设计步骤直接计算滴灌毛管管径和进口工作水头，无需进行任何复杂的试算。设计案例1表明在多数地形条件下，利用该文方法设计单向毛管的结果与传统方法设计结果的相对误差不超过4%；设计案例2表明该文方法设计双向毛管的结果与其他2种常用方法设计结果的最大相对误差为4%。因此，从工程实践角度，利用该方法设计的滴灌毛管管径和进口工作水头与其他传统方法设计结果非常接近。相比于传统设计方法，该方法简便实用，可以直接应用于滴灌工程设计。该研究可为改进滴灌毛管优化设计提供理论依据。
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| 关 键 词： | 灌溉 滴头 流速 滴灌 流量偏差率 管径 解析方法 |
| 收稿时间： | 2015/7/29 0:00:00 |
| 修稿时间： | 2016/1/18 0:00:00 |
Simplified method for designing diameter of drip irrigation laterals based on emitter flow variation |
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| Ju Xueliang,Wu Pute,Weckler R. Paul,Zhu Delan and Zhang Lin.Simplified method for designing diameter of drip irrigation laterals based on emitter flow variation[J].Transactions of the Chinese Society of Agricultural Engineering,2016,32(5):14-20. |
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| Authors: | Ju Xueliang Wu Pute Weckler R Paul Zhu Delan and Zhang Lin |
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| Institution: | 1. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China; 2. Institute of Water Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling 712100, China;,1. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China; 2. Institute of Water Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling 712100, China;,3. Department of Biosystems and Agricultural Engineering, Oklahoma State University, Stillwater 74078, USA;,2. Institute of Water Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling 712100, China; and 1. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China; 2. Institute of Water Saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling 712100, China; |
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| Abstract: | A simple, direct, and easily adaptable analytical approach was developed for determining the appropriate diameter of the drip laterals laid on uniformly sloping grounds. The emitter flow variation was used as the index of water application uniformity. A diameter design parameter was developed by reformulating the analytical expressions of emitter flow variation of the single inlet lateral and paired laterals. The relationship between parameter and pressure loss ratio were expressed by the graphs and formulas. For the specific value of velocity exponent, the condition for designing the diameter of a single inlet lateral was the calculation parameter lying between -1 and≤2.801, between -1 and≤2.859 and between-1 and≤4, respectively; meanwhile, the condition for designing the diameter of the paired laterals was the calculation parameter lying between 0 and≤3.143, between 0 and≤3.183 and between 0 and≤4, respectively. On the other hand, for the required emitter flow variation and emitter design discharge, there would be one or two solutions of diameter for a single inlet lateral, and one, two or numerous solutions for the paired laterals. Based on the ranges of the parameter, the design equations for the diameter of the single inlet lateral and paired laterals were derived with the pressure loss ratio as the design variable. The analytical expressions of inlet working pressure head of drip laterals were also simplified based on the energy gradient line method. When the emitter design flow, emitter flow variation criterion, and lateral length were provided, the diameter and inlet working pressure head of the drip laterals could be easily calculated without performing complex computer operations or tedious computations. In case 1, the differences in the designed parameters of a single inlet lateral from the proposed approach and variable discharge method are less than 4% for most ground slopes. In case 2, the maximum deviation in the design parameters of the paired laterals from the proposed approach and previous two methods was≤4%. These 2 cases indicated that the proposed approach could produce accurate results as those of the previous methods for practical purposes. By using the developed analytical expressions and regression relationships, the proposed approach provided a more simplified and adaptable design procedure than the traditional methods. This research could provide valuable information for improving the hydraulic design of drip irrigation system. |
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| Keywords: | irrigation nozzles flow rates drip irrigation emitter flow variation diameter analytical technique |
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