【作者】 杨亚军；

【导师】 林其钊；

【作者基本信息】 中国科学技术大学 ， 工程热物理， 2014， 硕士

【摘要】 引射器具有结构简单、成本低、维护和操作方便等特点,因此在制冷、航空航天、轻化工等工业领域中得到了广泛的应用。针对引射器内部复杂的流场,实验研究具有局限性。随着计算机的发展以及计算流体力学软件的不断更新,可以采用数值模拟的方法准确模拟出引射器内部流场的分布,这对引射器的优化设计,具有重要的意义。本文首先介绍了课题的研究背景及现状,确定了研究方法和内容；其次,通过计算得出了引射式燃烧器的基本尺寸；再次,对计算软件Fluent做了介绍；最后,借助于Fluent软件对引射式燃烧器进行了数值模拟,得到了引射式燃烧器内部的速度分布、工作流体流量、被引射流体流量。研究了影响引射式燃烧器引射效率的主要因素：几何参数(被引射入口与喷嘴的当量直径比、出口直径、喷嘴位置、喷嘴直径、喉口直径、喉口长度与扩压室长度比值等)和工况参数(工作压力、被引射压力、引射背压等)。研究结果表明：在工况参数不变时,引射式燃烧器的结构参数对引射系数的影响规律如下：1.当量直径比小于0.6时,随着当量直径比的增大,引射系数增大,当量直径比大于0.6时,随着当量直径比的增大,引射系数基本不变。2.在不同当量直径比下,随着出口直径的不断增大,引射系数不断地降低,并最终出现临界出口直径；3.随着L1/L2的增大,即喷嘴的位置远离吸收室入口处,引射系数降低；4.随着喷嘴直径的增大,引射系数降低；5.随着混合室喉口直径的增大,引射系数降低；6.随着喉口与扩压室长度比值的增大,引射系数增大。在结构参数不变时,引射式燃烧器的工况参数对引射系数的影响规律如下：1.随着工作压力的增大,被引射流体流量基本不变,工作流体流量不断地增大,结果就是引射系数不断地下降；2.随着被引射压力的增大,引射系数和被引射流体流量都增大；3.随着引射背压的增大引射系数和被引射流体流量都降低,并且当量直径比越大,下降的速度越快。更多还原

【Abstract】 The structure of ejector is simple and easy to manufacture. It is convenient to operate and thus has been widely used in cooling, aerospace application, light chemical engineering, and other industrial applications. For the complex flow field of ejector, experimental study has its limitations. With the continuous development of computer skills and the innovation of fluid dynamics, it can use numerical simulation accurate simulation the complex flow field of ejector, which has important significance for ejector optimization design.First, we introduce research background and current situation, determine the research methods and content; Secondly, we calculate the ejector burners basic dimensions; Once again, we introduce the software Fluent; At last, we use Fluent to simulation the ejector burner, calculate the ejector burner velocity distribution, the operating flow, the ejected mass flow, study the main factors affecting the ejector burner. Study the geometric parameters (the equivalent diameter ratio of ejected inlet and nozzle inlet; outlet diameter; the position of nozzle; the diameter of nozzle; the throat diameter of primary nozzle; the ratio of throat length and the diffuser chamber length) and the operating parameters (operating pressure; ejected pressure; ejector backpressure). The main results show that:Under the same operating parameters of ejector burner, the geometric parameters that impact for ejector burner as follows:l.When the equivalent diameter ratio less than0.6, with the increase of the equivalent diameter ratio, the ejecting coefficient increased; When the equivalent diameter ratio greater than0.6, the ejecting coefficient basically unchanged;2. With the increase of the outlet diameter, the ejecting coefficient decreased, in the end there will be a critical outlet diameter;3. With the increase of the L1/L2, i.e., the position of the nozzle away from absorption chamber entrance, the ejecting coefficient decreased;4. With the increase of the diameter of the nozzle, the ejecting coefficient decreased;5. With the increase of the diameter of the mixing chamber, the ejecting coefficient decreased;6. With the increase of the ratio of throat length and the diffuser chamber length, the ejecting coefficient increased;Under the same geometric parameters of ejector burner, the operating parameters that impact for ejector burner as follows:1. With increase of the operating pressure, ejected mass flow almost remained the same, but the mass flow of the operating fluid continued to increase, which resulted in the continuous decrease of the ejecting coefficient;2. With the increase of the ejected pressure, both ejecting coefficient and ejected mass flow increased;3. With the increase of the ejecting backpressure, both ejecting coefficient and ejected mass flow decreased. Furthermore, with larger equivalent diameter ratio, the rate of decreasing was larger.更多还原