喷射器结构优化及其在电厂中的应用研究

发布时间：2018-07-23 17:03

【摘要】：基于喷射器的应用特性，对可调式喷射器进行了结构优化，利用突片和旋流掺混理论，在喷射器喷嘴出口处加装突片或旋流叶片，以较小的射流核心的能量损失获得喷射系数的大幅提高。针对这两种结构优化思路，以某型号可调式喷射器为基础模型，对不同高度、安装个数及安装角度的突片和旋流叶片进行了数值研究。得出了温度、压力、速度和引射流量比等多组计算数据，并对喷射器内部流场进行了定性分析；研究了突片、旋流叶片的结构及安装形式对可调式喷射器引射特性的基本影响规律；实现了以较小的射流核心能量损失获得喷射性能大幅提升的目的。此外，从数值计算结果来看，突片式和旋流式喷嘴射流结构均能够明显的增强高、低压流体掺混性能，改善混合效果，使下游速度、压力及温度分布更加均匀。同时，本文针对某火电厂辅助蒸汽系统进行了研究，分析了系统中不同蒸汽用户汽源参数选择的合理性，提出了利用引射汇流装置（喷射器）对其进行改进，并进行了实例计算。结果表明，利用引射汇流装置不仅减少了阀门调节的节流损失，利于蒸汽用户的压力调节，并且随着引射能力的增强，系统节能效果也大幅提升。总体来看，与传统的可调式喷射器相比，突片式和旋流式喷射器的掺混性能和引射能力均有较大提高，且旋流式喷射器效果优于突片式喷射器；喷射器在电厂辅助蒸汽系统中的应用，节能效果明显，系统接入方便、安全，具有广泛的应用前景。通过本文的数值计算研究，，在现有可调式喷射器的基础上对其结构优化进行了有益的尝试，得出了一些有关突片式喷嘴和旋流式喷嘴的初步结论，对喷射器的优化设计和的进一步研究具有一定参考意义。
[Abstract]:Based on the application characteristics of the ejector, the structure of the adjustable ejector is optimized. By using the theory of jet and swirl mixing, the nozzle outlet of the ejector is equipped with a jet blade or swirl blade. The jet coefficient is greatly increased with the smaller energy loss of the jet core. Aiming at these two kinds of structural optimization ideas, based on a model of adjustable ejector, numerical study was carried out on different height, installation number and installation angle of flaps and swirl blades. The temperature, pressure, velocity and jet volume ratio are obtained, and the flow field inside the ejector is analyzed qualitatively. The basic influence of the structure and installation of swirl blade on the ejection characteristics of adjustable ejector has been achieved, and the purpose of improving jet performance greatly with smaller core energy loss of jet has been achieved. In addition, from the results of numerical calculation, the jet structure of the jet can obviously enhance the mixing performance of low pressure fluid, improve the mixing effect, and make the downstream velocity, pressure and temperature distribution more uniform. At the same time, this paper studies the auxiliary steam system of a thermal power plant, analyzes the rationality of the selection of steam source parameters of different steam users in the system, and proposes to improve it by means of ejector (ejector). An example is given. The results show that the ejection confluence device not only reduces the throttling loss of valve regulation, but also benefits the pressure regulation of steam users, and with the enhancement of ejection capacity, the energy saving effect of the system is greatly improved. On the whole, compared with the traditional adjustable ejector, the mixing performance and ejection ability of the ejector are improved greatly, and the effect of the swirl ejector is better than that of the ejector. The application of ejector in auxiliary steam system of power plant has obvious energy saving effect, convenient access and safety, and has wide application prospect. Based on the existing adjustable injector, a useful attempt has been made to optimize its structure through the numerical calculation in this paper, and some preliminary conclusions have been drawn about the inrush nozzle and swirl nozzle. The optimization design and further study of the ejector have certain reference significance.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621

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