【作者】 胥标；

【导师】 龙天渝；

【作者基本信息】 重庆大学 ， 市政工程， 2010， 硕士

【摘要】 在构建低碳经济、倡导可持续发展的当今社会,水源热泵技术作为一种可靠的具有高效节能、减碳效果的可再生能源应用技术近年来在我国得到了迅速的发展。充足的水源和良好的水质条件是应用水源热泵技术的基础条件,论文以重庆主城区应用地表水源热泵技术为背景,从计算流体力学角度研究了专门针对嘉陵江、长江水质中含沙量过高而设计的新型翼片斜板取水头的内部流场及其对沙粒的分离性能,并探讨了不同入口水流速度、不同密度差、不同结构参数条件下翼片斜板取水头对固体颗粒的去除效果的优劣。论文通过对固液两相流理论的研究与计算流体力学基本控制方程的分析,确立了采用湍流雷诺模型以及离散相模型对翼片斜板取水头中固液两相流进行数值模拟的计算方案,并以设计的中试装置的结构参数为基础对翼片斜板取水头的分离性能以及内部流场进行了数值模拟。通过计算单一粒径颗粒在翼片斜板取水头内的分离效率,得到了该新型翼片斜板取水头的分离效率图,结果表明该翼片斜板取水头对10微米级以上粒径的颗粒去除率可达40%以上;通过计算得到的流场结果显示,有压流条件下的翼片斜板取水头内部流场呈明显的平行流动和环形流动两个区域,并且环形流动的翼片格子区域内的水流速度相比于平行流动的主流区要小很多,这一特殊的流场特性对于进入翼片格内的沙粒等固体颗粒物的去除非常有利;通过对比不同入口水流速度、固液两相间不同密度差条件下该新型取水头对固体颗粒的去除效率发现,水流速度和两相密度差这两大因素对取水头的去除效率都有较大影响。论文从取水头对固体颗粒的去除规律与试验结果进行了对比验证,结果表明数值计算所得到的结果与试验结果基本吻合,从而证明了我们所建立的计算模型和选择数值计算方案的正确性。采用已被证实为正确的计算模型和数值计算方案就翼片斜板结构的主要结构参数(翼片格数N、翼片宽度B、斜板宽度h和斜板倾角θ)对固体颗粒的分离性能的影响作了研究,并就各参数对分离性能的影响作了定性分析,得出了使取水头出水所含颗粒最少时的结构参数值。论文中研究有压流条件下翼片斜板结构的取水头的内部流场和固液两相流中固体颗粒的分离效率所确立的数值计算方法,能够为实际工程中设计的类似取水头部性能的研究提供一种新的思路和可靠的方法,具有一定的参考价值。更多还原

【Abstract】 In modern society that builds low carbon economy and promotes sustainable development, as a reliable, energy efficient and carbon reducing renewable energy application technology, the water source heat pump technology (WSHP) has been developed rapidly in recent years in China. Sufficient water source and good water quality condition are the basic conditions for application of WSHP technology. Based on application of WSHP technology in Chongqing city, from the perspective of computational fluid dynamics, this paper studies the internal flow field and separation performance of the new water intake head with inclined vane plates designed for high sediment concentration in Jialing River and Yangtze River water, and discusses the performance of the new water intake head with inclined vane plates removing solids under the different inlet water velocity, the different density contrast, and the different structural parameters.In this paper, through studying the liquid-solid two-phase flow theory and analyzing the basic equations of computational fluid dynamics, the numerical simulation method for solid-liquid two-phase flow in the water intake head with inclined vane plates by use of turbulent Reynolds Model and Discrete Phase Model was established, the separation performance and internal flow field of the new water intake head based on the designed structural parameters of pilot-plant are simulated.By calculating the separation efficiency of single size particles in the new water intake head with inclined vane plates, its separation efficiency diagram was obtained. The results showed that the removal efficiency of particle that its size is more than 10 micron, can reach above 40% in this new water intake head. The computational flow field results showed that the internal flow field in the new water intake head with inclined vane plates is obvious parallel flow and annular flow., and the water velocity of annular flow in vane grid region is much lower than that of parallel flow in mainstream area, which is very favorable to remove sand and other solid particles in vane grid region. By comparing the removal efficiency under the conditions of different inlet water velocity and solid-liquid two phase density contrast, we found that water velocity and density contrast have great influence on the removal efficiency of this new water intake head. The laws of the new water intake head removing solid particles were compared with experiment results, which proved that the results of numerical calculation were almost the same as experiment results, and proved that our computation model and numerical calculation solution is correct.The separation performance of water intake head with inclined vane plates removing particles influenced by its main structural parameters, including vane number N, vane width B, inclined plate width h, and inclined plate tilt angleθwas studied by use of the correct calculation model and numerical simulation solution that had been confirmed. Through qualitative analysis, the optimum structural parameter values to make effluent water contain minimum particles were obtained.In this paper, we established a numerical calculation method of studying the internal flow field of the new water intake head with inclined vane plates and solid-liquid two phase separation efficiency of solid particles under the conditions of pressure flow, which provides a new idea and reliable methods for similar research on the performance of water intake head and has certain reference value in actual engineering design.更多还原