低压管道灌溉放水阀的水力特性研究

发布时间：2018-05-28 22:16

  本文选题：低压管道灌溉 + 球阀　； 参考：《扬州大学》2017年硕士论文

【摘要】：进入21世纪后,随着技术的进步和经济的进一步发展,人类对节水、节地、生态、高产优质有了更高的要求,低压管道输水灌溉技术也成了现阶段农业发展的重要措施。要想加快发展速度,管材和配水装置的研究是最重要的两项,目前管材的研制已普遍受到重视,而配水装置的研制却是一个薄弱环节,严重阻碍了该项技术的推广应用,急需提出一种简易、低水头损耗、密封性良好的新型放水阀。本文采用计算流体力学软件FLUENT,通过UG构建模型,采用四面体非结构化网格自动划分网格,计算采用气液二相流VOF模型,Standard k-ε紊流模型,以及SIMPLE算法。通过对下压式挡板放水阀中一种过流能力最大的工况建立三维数值模型,利用Flunet软件模拟的几组流量情况,得出计算模型可靠的结论。同时对比了不同流量下相同断面速度、流态、压强的差异,分析了可能的原因。通过对新型低压灌溉球型放水阀建立三维数值模型。利用Fluent模拟分析了在相同的工作水头下,不同转角下放水阀阀内的水流流态,水头损失和过流能力,分析得出球阀的的适宜工作的转角在0°至25°之间。同时模拟了相同过流流量下,球阀全开工况与下压式挡板放水阀全开工况的水头损失、压强的对比,分析得到球型放水阀无论是在工作环境的适应性、密封性能、过流能力还是减少水头损失上都比下压式挡板放水阀更具优势。本文研究的结果将用于分析阀体结构内部水流情况,分析阀体内部对水流的阻力,为对进一步优化阀体结构减小水流阻力提供参考和依据。
[Abstract]:After entering the 21st century, with the progress of technology and the further development of economy, people have higher requirements for water saving, land conservation, ecology, high yield and good quality. The irrigation technology of low pressure pipeline water conveyance has also become an important measure for the development of agriculture at this stage. In order to speed up the development, the research of pipe and water distribution device are the two most important items. At present, the development of pipe material has been paid more attention to, but the development of water distribution device is a weak link, which seriously hinders the popularization and application of this technology. It is urgent to put forward a simple, low head loss, good sealing new discharge valve. In this paper, the computational fluid dynamics software fluent is used to construct the model by UG, the tetrahedron unstructured grid is used to mesh automatically, the gas-liquid two-phase flow VOF model is used to calculate the standard k- 蔚 turbulence model, and the SIMPLE algorithm is used. By establishing a three-dimensional numerical model for a working condition with maximum overflow capacity in a downpressure baffle discharge valve, and using several groups of flow conditions simulated by Flunet software, the reliable conclusion of the calculation model is obtained. At the same time, the differences of the same cross section velocity, flow state and pressure under different flow rate are compared, and the possible reasons are analyzed. A three-dimensional numerical model was established for a new type of low-pressure irrigation ball discharge valve. The flow pattern, head loss and overflow capacity of the valve under the same working head are simulated by Fluent. The suitable working angle of the ball valve is found to be between 0 掳and 25 掳. At the same time, the comparison of the head loss and pressure between the ball valve and the downpressure baffle valve under the same overflow flow rate is simulated. The results show that the ball outlet valve is fit for the working environment and the sealing performance is not only in the working environment, but also in the whole open condition. Overflowing capacity or reducing head loss are superior to lower pressure baffle discharge valves. The results of this paper will be used to analyze the internal flow of the valve body and the resistance of the body to the flow, which will provide a reference and basis for further optimization of the valve body structure to reduce the flow resistance.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S277.9
，

本文编号：1948386