【作者】 王虎；

【导师】 李少华；

【作者基本信息】 东北电力大学 ， 工程热物理， 2006， 硕士

【摘要】 横向紊动射流是流体运动的一种重要类型,它广泛存在于工程实际应用中,对横向紊动射流流场结构、流动机理的研究具有重要的学术意义,同时对解决工程应用中存在的许多问题具有指导作用。本文对不同入射角横向紊动射流的流场进行了数值模拟和实验分析,系统地分析了横向紊动射流的流场结构和流动机理。首先,采用标准K-ε模型和RNGK-ε模型对不同入射角横向紊动射流问题进行了数值模拟,结果表明RNGK-ε模型对横向紊动射流流场的预测能力比标准K-ε模型有所改进。求解的计算区域包括主气流通道和射流出射喷管,分别用适体坐标方法生成结构化网格和非结构化网格,使计算准确度得到了提高。.其次,建立了用于测量横向紊动射流的实验台,并利用IFA 300型热膜风速仪系统测量了多种工况下的流场,并将速度、湍动能结果与数值计算结果进行了比较,实验结果与数值模拟结果吻合较好,从而为分析流场特性、比较湍流模型以及验证数值计算方法提供了依据。计算了射流入射角变化时的流场,计算结果给出了不同M和α等工况下的速度场、湍动能的变化,分析了流场在沿流动方向、纵向及垂直方向不同截面内的发展变化规律。结果表明:射流正向倾斜入射时,射流起始段增加,在垂直方向对主流场的影响区域减小,射流喷口上游位置处的“孔吸流动”更为明显,射流出口下游背风侧的分离现象逐渐减弱。更多还原

【Abstract】 A turbulent jet issuing transversely into a uniform cross-flow is an important type of fluid flow and can be found in many engineering applications. It is of both academic and applied value to research its structural features and flow mechanisms. In this paper, the numerical simulation and experimental studies have been performed in order to understand the characteristics of the turbulent jets in cross-flow, and the result is analyzed.The normal K-εturbulence model and the RNGK-εturbulence model are used respectively to simulate the different injection angles turbulent flows, and the results show that the prediction performance of the RNGK-εmodel is better when simulating the turbulent jets in cross-flow. The computational domain consists of two parts, the main stream duct and the jet hole, where grids are generated respectively structured grid and unstructured grid in the body-fitted coordinates. The girds near the wall and the jet hole are got finer.The experimental set up for the turbulent jets in cross-flow is designed, and the hot wire anemometry IFA 300 is used to measure the velocity field and the turbulent kinetic energy, and the computational result matches experimental measurement reasonably well. The experimental result is very important in the analysis of the flow field, check of the turbulence model and validation of the numerical method.The flow fields are simulated in the conditions of positive different injection angles; the velocity fields, and turbulent kinetic energy fields are got in different conditions of M andαthe evolution of flow patterns on the centre planes, and both the transverse and vertical planes are analyzed. It can be concluded that, when the jet is injected at positive angles, the initial section of the jet increases and the region affected by the jet decreases in the vertical direction; moreover, the circumfluence toward the jet exit becomes more obvious, and the separation events in the lee of the jet weaken.更多还原