【作者】 王海军；

【导师】 白丹；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2010， 硕士

【摘要】 滴头制造偏差影响到田间管网灌水均匀性,但目前在滴灌田间管网水力设计计算中较少考虑这一问题,导致田间管网设计和实际运行存在偏差。本文采用室内试验、数值模拟和理论分析相结合的方法,系统的分析了紊流迷宫内镶式滴头制造偏差对田间管网技术指标的影响,为滴灌系统的设计及运行管理提供理论依据,主要研究成果如下：(1)在滴头水力特性室内试验的基础上,分析实验数据,针对流量偏差率作为滴头制造偏差的不足之处,对滴头制造偏差重新定义。分析得出滴头流量、滴头制造偏差、流态指数、流量系数均服从正态分布的。以流态指数、流量系数为随机变量对滴头流量进行计算机二维随机模拟,并对模拟结果进行验证,模拟结果与实验结果吻合良好。(2)考虑滴头制造偏差影响,建立滴灌毛管水力计算模拟模型,运用MATLAB进行编程。应用这一模型,分析不同要素组合条件下的毛管水力要素变化规律,结果表明,考虑滴头制造偏差与未考虑滴头制造偏差相比,毛管压力和滴头流量会有一定的波动,其中滴头流量波动比较明显。(3)考虑滴头制造偏差影响,建立田间管网的数值模拟模型,运用MATLAB进行编程。应用此模型,分析了不同要素组合条件下的灌水过程中田间管网系统压力水头偏差率、流量偏差率和管网系统灌水均匀系数的变化情况。结果表明,压力水头偏差率、流量偏差率、灌水均匀度变化趋势与未考虑滴头制造偏差影响时总体变化趋势相接近,但滴头制造偏差对田间管网技术指标的影响很大,灌水质量明显下降,其中压力水头偏差率、流量偏差率随着滴头制造偏差系数的增大而增大,灌水均匀度随着滴头制造偏差系数的增大而减小。在考虑滴头制造偏差影响的基础上,对滴灌压力水头偏差率和流量偏差率之间关系的经验公式进行了修正,显著性检验表明公式是可行的。更多还原

【Abstract】 Emitter manufacture deviation affect the irrigation uniformity of field pipe network, but the present of hydraulic design calculation less consider this question in the field pipe network, so it lead to exist bias between design and practical operation. Based on laboratory test and theoretical analysis, numerical simulation method, the combination of the system are analyzed non-compensated of emitter manufacturing deviations, and the influence of technical indexes for drip irrigation system design and operation management theory are offered, the main research results are as follows:(1) In the hydraulic characteristics of emitter laboratory test, analysis of experimental data, based on the inadequate of flow deviation rates as the emitter manufacture deviation, the emitter manufacture deviation are redefined. Analysis of emitter flow, emitter manufacture deviation, flow index, flow coefficients obey the normal distribution. Base on the random variable of flow index and flow coefficient to computer simulation about the emitter flow, through the two random simulation results verified the results accord with the requirement, the simulation results are in good agreement with the experimental results.(2)As consideration of emitter manufacture deviation, the numerical simulation model of drip irrigation lateral hydraulic calculation which use MATLAB programming are established. Through using the model, the variation of lateral hydraulic factors under different conditions could be analysed, the results showed that the change rule which consider emitter manufacture deviation and does not consider emitter manufacture deviation, the lateral pressure and discharge rate will have certain fluctuation, and emitter flow volatility is obvious.(3) As consideration of emitter manufacture deviation, the model of field pipe network numerical simulation which use MATLAB programming are established. The model was applied to the analysis of different factors, the process of water under the condition of the pipeline system pressure, flow rate deviation head deviation and pipeline irrigation uniformity coefficient of variation. Results show that the pressure head, flow rate deviation error rate, irrigation evenness change trend and does not consider emitter manufacture deviation affect overall trend when is close, but the deviation emitter manufacturing network technology index, the influence of water quality decreased obviously, pressure, flow rate deviation head emitter along with deviation ratio of manufacture deviation coefficient increases, irrigation uniformity coefficient of emitter along with the manufacturing error decreases. In consideration of emitter manufacture deviation, on the basis of the influence of pressure head deviation ratio and drip irrigation flow rate deviation between the empirical formula was revised, significant test shows that formula is feasible.更多还原