滴灌双向流道稳流性与抗堵性对流道结构参数的响应分析

The bidirectional flow channel of drip irrigation emitter is a new type of channel, in which pressure bidirectional flows with positive and negative direction strongly blend when they meet in channel with high steady stream, well anti-clogging, low manufacture deviation and little cost . In experiment and research, computational fluid dynamics (CFD), particle image velocimetry (PIV) , rapid prototyping, orthogonal experiment, uniform design, mathematical statistics, support vector machine, the response surface analysis, multiple objective optimization and genetic algorithm are used based on the characteristics of flow field in bidirectional flow channel in micro-thin channel and. The Research Includes: (1)The experiment and influencing factors analysis of steady stream and anti-clogging in bidirectional flow channel; (2)CFD numerical simulation method of bidirectional flow channel; (3)The mechanism and index response surface of steady stream in bidirectional flow channel;(4) The mechanism and index response surface of anti-clogging in bidirectional flow channel;(5) The structure parameters response analysis and optimization design of in bidirectional flow channel. Research objectives is to reveal the inner relationship of structure parameters, pressure, flow rate, steady stream and anti-clogging and to propose design theory for bidirectional flow channel. Research results will be used for to develop drip emitter, drip irrigation pipe and thin-wall drip irrigation belt of bidirectional flow channel, in order to improve independent innovation capability, R&D efficiency and the level of technology in developing the drip irrigation emitters with bidirectional flow channel.

双向流流道是一种新型滴灌灌水器流道，有压水流在该流道中形成正、反双向水流，两个方向的水流汇合后强烈混掺，该流道具有稳流性高、抗堵性好、制造偏差小和生产成本低等特点。基于滴灌双向流微细流道内双向流流场特征，运用计算流体动力学(CFD)、粒子成像测速（PIV）、快速成型、正交试验、均匀设计、数理统计、支持向量机、响应面分析、多目标优化和遗传算法等理论与技术开展试验研究，内容有：(1)双向流道稳流与抗堵性能试验及其影响因素分析；(2)双向流CFD数值模拟方法；(3)双向流流道稳流机理和稳流指标响应面；(4)双向流流道抗堵机理和抗堵指标响应面；(5)双向流流道结构参数响应分析和优化。旨在揭示双向流流道结构参数、压力、流量、稳流性和抗堵性的内在联系，提出双向流流道设计理论。成果将用于双向流滴灌灌水器、滴灌管和薄壁滴灌带等系列产品的研发，以提升滴灌灌水器研发的自主创新能力、研发效率和技术水平。

双向流流道是一种新型滴灌灌水器流道，有压水流在该流道中形成正、反双向水流，两个方向的水流汇合后强烈混掺，该流道具有稳流性高、抗堵性好、制造偏差小和生产成本低等特点。通过研究，揭示了双向流流道结构参数、压力、流量、稳流性和抗堵性的内在联系，提出双向流流道设计理论。研究内容包括：(1)双向流道稳流与抗堵性能试验及其影响因素分析；(2)双向流CFD数值模拟方法；(3)双向流流道稳流机理和稳流指标响应面；(4)双向流流道抗堵机理和抗堵指标响应面；(5)双向流流道结构参数响应分析和优化。研究成果主要有（1）针对所研究的流道特点，分别采用了5种模型计算不同流道进口压力的流场，并与PIV流场实测信息和流量实测值对比，表明标准k-ε模型适合双向流道；提取了5个反映流道几何特征的结构参数，数值模拟方案的流态指数为0.4428-0.5025，水力性能优于迷宫流道。（2）分别运用颗粒随机轨道模型和欧拉模型模拟双向流道抗堵性能，根据欧拉模型计算结果，沙粒直径对流道内最大颗粒沉积率影响显著。根据颗粒随机轨道模型计算结果，数值模拟方案中流道的颗粒通过率为0.588-0.901，分水件与挡水件底距离、挡水件底高度和分水件与挡水件最小距离三个流道结构参数对颗粒通过率影响显著；利用Fluent模拟的可视化功能，看找出双向流道内易堵塞区域，通过改变挡水件底部拐角的形状，增加开阔区流速，提高抗堵性能。（3）构建了稳流性能指标和抗堵性能指标响应面，在此基础上，建立了双向流流道优化设计模型，优化流道流态指数为0.4512，而其颗粒通过率为0.967。上述成果和方法可用于用于双向流滴灌灌水器、滴灌管、薄壁滴灌带、涌泉灌溉稳流器、微灌压力调节器、压力管道减压阀和静态混合器等系列产品的研发。