【作者】 刘春景；

【导师】 郑加强； 周宏平；

【作者基本信息】 南京林业大学 ， 机械设计及理论， 2009， 博士

【摘要】 本文针对滴头内部流场研究领域存在的主要问题,以滴头流道设计与优化为研究对象,通过理论分析、数值模拟、试验验证等进行研究。主要研究内容与结论如下:(1)给出了基于滴灌滴头的宏观与微观尺度流体力学理论。典型迷宫滴头流道内部流态转捩雷诺数Re≤500。提出将多学科设计优化思想应用到滴头产品的设计,实现滴灌滴头产品的优化设计。(2)将一种基于改进PSO最小二乘支持向量机的预测模型引入滴灌滴头水力性能预测领域。该模型能方便地预测三角形迷宫流道关键参数对滴头水力性能的影响,有助于准确认识滴头水力性能随流道结构参数的变化规律。(3)构建了梯形迷宫流道的液固两相流理论模型,研究了滴头内液固两相流的流动特性,考察了滴头内液固两相流的压降、两相浓度分布以及流体流速对液固两相流动的影响。(4)利用响应曲面法研究了梯形迷宫滴头流道的关键参数对滴头水力性能的影响。采用基于Optimus与Fluent相结合的方法对滴头进行了优化设计,优化后的滴头水力性能得到了提高。(5)在Visual C平台上编制基于UG/NX5.0的三维参数化设计软件,实现滴头的三维实时参数化设计。更多还原

【Abstract】 The hydraulics performance and the internal flow field of drip irrigation emitter are studied through theoretical analysis, numerical simulation and experimental verification. The research contents and conclusions are as follows:(1) Based on drip irrigation emitter, the macro-scale and micro-scale hydromechanics theory are presented. The relationship between flux and pressure is analyzed. Transition Reynolds number of typical emitter labyrinth channel is less than 500. Multidisciplinary design optimization idea is proposed for drip irrigation emitter design. Drip irrigation emitter will have optimal hydraulic performance when MDO is integrated with virtual prototyping technique to optimize the design parameters of emitter.(2) A novel prediction model based on modified PSO least square support vector machine is proposed. The effects of triangle labyrinth channel parameters on hydraulics performance of emitter can be predicted with the limited test data, thus the variation law of hydraulics performance of drip irrigation emitter following labyrinth channel parameters can be obtained.(3) Liquid-solid two-phase theory model was been constructed firstly. The flow characteristic of liquid-solid two-phase in drip irrigation emitter is studied. The influences of liquid pressure drop, concentration distribution and velocity in drip irrigation emitter to liquid-solid two-phase flow characteristic are investigated.(4) Trapezium labyrinth emitter channel has five key parameters, the influence of these five key parameters to hydraulic performance of drip irrigation emitter are carried out by using the Box-Benhnken response surface methodology. Being combined the Multidisciplinary design optimization software OPTIMUS with the computational fluid dynamics software FLUENT to optimize the design of emitter, in the meantime, hydraulic performance has been completely improved after optimization.(5) The three-dimension parameter design software UG/NX 5.0 is compiled under the environment of visual C++, the model is driven by program, realizes the parameter and series design of drip irrigation emitter, and establishes basis for fluid field analysis for next step.更多还原