天然气径向旋流预混高压燃烧特性研究

发布时间：2018-06-07 07:02

本文选题：天然气 + 高压　；参考：《华北电力大学(北京)》2016年硕士论文

【摘要】：随着污染问题和能源危机的日益加重,寻求洁净可靠的能源代替煤炭发电成为亟待解决的问题。近年来以清洁天然气为燃料的燃气轮机发电及燃气-蒸汽联合循环得到极大发展。目前受材料限制,进一步提高初温已非常困难,高压比燃烧成为提高燃气轮机性能的新途径。鉴于目前国内外对天然气在高压下的径向旋流预混燃烧研究较少,本文在总结国内外燃烧实验台设计经验的基础上,设计了天然气高压燃烧实验台,对实验台重要参数进行设计计算,并使用流体动力学计算软件Fluent进行燃烧模拟,归纳总结出部分燃烧参数和工艺参数对高压下天然气旋流预混燃烧的影响规律,为今后实验台的搭建以及天然气高压燃烧的实验研究奠定理论基础。本文开展的工作和获得的成果如下：1.根据国内外燃烧室设计经验,结合天然气燃烧特性和高压条件,与生产厂家沟通协商后,设计了本高压燃烧实验台的基本结构和重要参数。燃烧采用预混燃烧形式,甲烷采用单管入口,空气流经径向旋流器形成旋流并与甲烷混合,燃烧室还包括二次风和冷却空气部分。接下来计算得到标准工况时气体管路设计参数和燃料喷嘴相关参数,为实验台和模型的建立提供参考。2.使用前处理软件Gambit对设计的高压燃烧实验台建立模型。为验证模型能否用于高压燃烧的模拟研究,从两方面测试模型网格的合理性：无化学反应冷态模拟和网格数量无关性验证。经测试,发现模型冷态模拟效果良好,网格数量48万时具有较好的网格无关性。3.利用流体计算软件Fluent模拟不同工况下的天然气高压预混燃烧情况,深入研究燃烧参数(如压力、过量空气系数、功率等)和工艺参数(进气温度、旋流度、预混段长度等)对天然气高压预混燃烧的影响规律,依次分析了高压条件下变工况、变参数时燃烧室温度场、流场、中心轴线温度速度分布、NOx生成、喷口下游中心低速区等的变化。经整理归纳得出天然气高压预混燃烧的部分基本规律,为天然气在燃烧实验台及燃气轮机中的稳定燃烧、低NOx排放提供理论依据,具有较大的实际意义。
[Abstract]:With the worsening of pollution and energy crisis, it is urgent to seek clean and reliable energy instead of coal power generation. Gas turbine power generation and gas-steam combined cycle with clean natural gas as fuel have been greatly developed in recent years. At present, it is very difficult to improve the initial temperature because of the limitation of materials. High pressure specific combustion is a new way to improve the performance of gas turbine. In view of the lack of research on the radial swirl premixed combustion of natural gas at high pressure at home and abroad, based on the summary of the design experience of the domestic and foreign combustion test bench, a natural gas high pressure combustion test bench is designed. The important parameters of the test bench are designed and calculated, and the combustion simulation is carried out by using the hydrodynamic calculation software Fluent. The influence of partial combustion parameters and technological parameters on the premixed combustion of natural gas swirling under high pressure is summarized. It lays a theoretical foundation for the construction of experimental bench and the experimental study of high pressure combustion of natural gas in the future. The work and results of this paper are as follows: 1. Based on the design experience of combustion chamber at home and abroad, combined with the combustion characteristics and high pressure conditions of natural gas, the basic structure and important parameters of the high pressure combustion test bench were designed after communicating with the manufacturer. The combustion is premixed, the methane is a single-tube inlet, the air flows through the radial cyclone to form a swirl and mixed with methane, and the combustion chamber also includes secondary air and cooling air. Then, the design parameters of gas pipeline and fuel nozzle are calculated under standard working conditions, which provides reference for the establishment of test bench and model. A preprocessing software Gambit was used to model the designed high pressure combustion test bench. In order to verify whether the model can be used in the simulation of high pressure combustion, the rationality of the model grid is tested from two aspects: cold state simulation without chemical reaction and mesh quantity independent verification. It is found that the model has good cold simulation effect and has good mesh independence when the number of meshes is 480,000. The high pressure premixed combustion of natural gas under different working conditions was simulated by the fluid calculation software Fluent. The combustion parameters (such as pressure, excess air coefficient, power, etc.) and process parameters (inlet air temperature, swirl fluidity, etc.) were studied in depth. The influence of the length of premixed section on high pressure premixed combustion of natural gas is analyzed in turn. The temperature field, flow field and temperature velocity distribution of central axis are analyzed in turn. The change of the low speed zone in the center of the nozzle downstream. Some basic laws of high pressure premixed combustion of natural gas are concluded, which provides a theoretical basis for the stable combustion of natural gas in combustion test bench and gas turbine and low NOx emission, which is of great practical significance.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK16

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