卷盘式喷灌机专用斜击式水涡轮内流分析及优化

发布时间：2018-07-24 12:43

【摘要】：农业是我国立国之本,目前我国农业机械化程度依然落后于发达国家,农业灌溉机械化仍然有很大发展潜力和空间。现阶段我国农业灌溉仍以地面灌溉为主,规模化作业水平较低。喷灌属于我国最早引进的先进灌溉方式,至今已在我国大部分农作物产区经过实践试验,未来喷灌将成为我国最主要的农业灌溉方式之一。卷盘式喷灌机作为最主要的喷灌装备,结构简单紧凑,移动便捷,可操作性强,人均工作量小等优点,自发明开始,就一直备受国内外青睐。我国引进卷盘式喷灌机以来,经过自主研究与开发,现已实现国产化,并形成了一定生产规模,不仅满足国内农业生产需要,而且开始出口,面向国际。我国卷盘式喷灌机的设计研发目前仅基于国外上世纪的旧机型,国内针对性的研究较少,因此,与国外先进机型相比,仍有较大差距,在动力驱动部件——水涡轮的差距更加突出。国内外针对水涡轮的研究几乎空白,国内生产企业也沿用国外旧型号水涡轮,不仅影响整机运行,同时也易因为组件之间不匹配造成不必要的损失。本文针对以上问题,在江苏省农业科技支撑计划项目BE2012385“低能耗自动卷盘式智能农业灌溉装备研究与开发”的资助下,基于试验研究、数值计算和理论分析,对JP75型卷盘式喷灌机专用斜击式水涡轮的水力性能展开了内部流动分析与优化设计。本文的主要创新研究有:1.利用水涡轮试验台对JP75型斜击式水涡轮开展水力性能试验。试验表明,水涡轮整体工作效率较低,最高效率仅为13.79%,其工作流量区极为有限。2.利用多重坐标系(MRF)方法对水涡轮展开稳态数值计算。为了选择合适的网格模型和湍流模型,对比了Realizableκ-ε模型和SSTκ-ω模型、四面体网格和多面体网格总共四种组合,最终确定了SSTκ-ω模型与多面体网格的计算设置,使数值计算与试验结果的误差相对较小,计算效率较高。3.针对JP75型斜击式水涡轮工作效率低,工作区间小的问题,对其不同转速、流量下的内流开展分析,并量化分析了水涡轮主要能量交换部件的能量交换效率。通过对压力、速度分布不均匀,梯度较大区域进行能量转换率计算发现,进口管道和转轮,两个过流部件的能量转换率较低,其中进口管道的能量转换率仅为26.31%,转轮的能量转换率仅为45.44%。4.基于正交试验方法,参考斜击式水轮机设计理论对水涡轮的主要几何参数进行了七因素三水平正交试验,并对试验结果进行了相关系数分析和主成分分析,最终确定了主要影响因素和最优参数组合,验证了优化模型不仅在设计工况下转速有了极大提升,同时也获得了更为宽泛的工作转速、流量区间。
[Abstract]:Agriculture is the foundation of our country. At present, the degree of agricultural mechanization still lags behind that of developed countries, and agricultural irrigation mechanization still has great development potential and space. At present, surface irrigation is still the main agricultural irrigation in our country, and the level of scale operation is low. Sprinkler irrigation is one of the earliest advanced irrigation methods introduced in our country. It has been tested in most of the crop producing areas in China. In the future, sprinkler irrigation will become one of the most important agricultural irrigation methods in our country. As the main sprinkler irrigation equipment, the coil irrigation machine has the advantages of simple and compact structure, convenient movement, strong maneuverability and low per capita workload. Since its invention, it has been favored at home and abroad. Since the introduction of coiled disk sprinkler irrigation machine in China, through independent research and development, it has been made domestically and has formed a certain scale of production, which not only meets the needs of domestic agricultural production, but also begins to export and faces the international market. At present, the design and development of the coiling and disc sprinkler irrigation machine in our country is based on the old models of the last century abroad, and there is less targeted research in China. Therefore, compared with the advanced models abroad, there is still a big gap. The gap in power-driven components-water turbines is even more pronounced. The research on water turbine at home and abroad is almost blank, and domestic production enterprises also use the old water turbine of foreign countries, which not only affects the operation of the whole machine, but also easily causes unnecessary losses because of the mismatch between components. In order to solve the above problems, based on experimental research, numerical calculation and theoretical analysis, this paper is supported by BE2012385 "Research and Development of Intelligent Irrigation equipment with low Energy consumption, automatic Coil and Disc Type", which is supported by Jiangsu Agricultural Science and Technology support Project. The internal flow analysis and optimization design of the hydraulic performance of the special oblique water turbine for JP75 type coil and disk sprinkler irrigation machine are carried out. The main innovation research in this paper is: 1. Hydraulic performance test of JP75 type oblique hammer water turbine was carried out by using water turbine test rig. The experimental results show that the overall efficiency of water turbine is low, the highest efficiency is only 13.79, and the working flow area is very limited. The steady-state numerical calculation of water turbine is carried out by using the (MRF) method of multiple coordinate systems. In order to select suitable mesh model and turbulence model, four combinations of Realizable 魏-蔚 model and SST 魏-蠅 model, tetrahedron mesh and polyhedron mesh are compared. Finally, the computational settings of SST 魏-蠅 model and polyhedron mesh are determined. The error between the numerical calculation and the test results is relatively small, and the calculation efficiency is higher. 3. Aiming at the problem of low working efficiency and small working range of JP75 type oblique stroke water turbine, the inner flow under different rotational speed and flow rate is analyzed, and the energy exchange efficiency of main energy exchange components of water turbine is analyzed quantificationally. By calculating the energy conversion rate of the inlet pipeline and the runner, the energy conversion rate of the two flow passing parts is lower, through the calculation of the energy conversion rate of the pressure and velocity distribution is uneven and the gradient is large. The energy conversion rate of the inlet pipeline is only 26.31 and the energy conversion rate of the runner is only 45.44. 4. Based on the orthogonal test method, the main geometric parameters of water turbine are tested by seven factors and three levels, and the correlation coefficient and principal component analysis of the test results are analyzed according to the design theory of oblique hammer turbine. Finally, the main influencing factors and the optimal parameter combination are determined, and it is verified that the optimized model not only has a great increase in speed under the design condition, but also obtains a wider range of working speed and flow rate.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S277.94

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