燃气轮机燃烧室预混喷嘴排放性能的试验和数值研究

Experiment and Numerical Study on Emission Characteristics of Premixing Fuel Nozzle in Gas Turbine Combustor

关键词:  低排放  燃烧室  预混燃烧  化学反应器网络  燃气轮机

Key words:  Low emission  Combustor  Premixed combustion  Chemical reactor networks  Gas turbine

摘要:

为了研究当量比、值班燃料量和压力对燃气轮机燃烧室预混喷嘴排放指标的影响，在环境压力下按照等速模化原理进行了燃烧室预混喷嘴的燃烧试验，基于化学反应网络法构建了污染物预测模型，开展了试验和数值对比研究。结果表明：在带值班燃料的情况下该预混喷嘴当量比 φ在0.35~0.5时可满足国标排放要求，但是值班燃料量增大会使NO _x 排放升高；在 φ<0.4时，压力对纯预混燃烧NO _x 生成无影响， φ>0.4时，NO _x 会随压力升高而增多；带有值班燃料的预混燃烧时，NO _x 对压力变化敏感，压力升高导致NO _x 增多；该预混喷嘴混合性能对空气流速不敏感、燃料兼容性强，排放达标当量比范围宽，经进一步设计开发后有潜力应用于燃气轮机低排放燃烧室中。该化学反应器网络模型依赖经验较少，当值班燃料比例≤0.17时，对污染物预测与试验数据符合较好。

Abstract:

In order to study the effects of equivalence ratio, pilot fuel flowrate, and pressure on emission characteristics of premixing fuel nozzle in gas turbine combustor, combustion experiment on emission of premixing fuel nozzle were conducted at atmospheric pressure，and an emission prediction model based on chemical reactor networks was proposed. The experimental and numerical results indicated that the nozzle would meet the low NO _x emission standard at equivalence ratios from 0.35 to 0.5, but increasing pilot fuel flowrate would lead NO _x emission to increase. The increase of pressure have no effect on NO _x emission of pure premixed combustion at φ<0.4, otherwise, NO _x would rise with the increasing pressure. NO _x emission of premixed combustion with pilot flame was sensitive to pressure change and would increase as pressure increased. The premixing fuel nozzle, the mixing performance of which is insensitive to air velocity, which has strong fuel compatibility and a wide range of equivalence ratio to meet emission limit, has the potential to be used in low emission combustors of gas turbines after further development. The chemical reactor networks (CRN) model presented relies less on experience and the emission prediction of which is in good agreement with the experimental data when the ratio of pilot fuel to total fuel is no greater than 0.17.