燃气轮机进气喷雾冷却下层流火焰的特性

Characteristics of laminar flame under inlet spray cooling of gas turbines

建立了燃气轮机进气喷雾冷却条件下燃烧室的一维层流预混燃烧模型,研究了在不同化学当量比、温度和压力下H_(2)O体积分数对火焰传播速度、火焰温度、燃烧产物分布的影响.研究结果表明:火焰传播速度随H_(2)O体积分数升高而近似线性减小,采用进气雾化冷却技术时,可适当提高燃烧室中扩散燃烧所占比例,以此来稳定燃烧工况;火焰温度随混合气中H_(2)O体积分数升高而急剧降低,燃烧尾气排放中NO_(x)体积分数降低;CH_(4)燃烧过程中H_(2)O降低了O,H,OH自由基的体积分数,高H_(2)O体积分数下基元反应R38对促进CH_(4)燃烧的作用效果减弱,火焰传播速度降低.

A one⁃dimensional laminar premixed combustion model for gas turbine combustor under inlet spray cooling was established.Under different factors of temperature,chemical equivalence ratio and pressure,the effects of H_(2)O on the flame propagation speed,flame temperature and product distribution were studied.The findings show that the laminar flame speed decreases approximately linearly with the increase of H_(2)O volume fraction.When the inlet pray cooling is adopted,the proportion of diffusion combustion in the combustion chamber can be appropriately increased to stabilize the combustion condition.The flame temperature and the NO_(x) in the combustion tail gas decrease sharply with the increase of the H_(2)O volume fraction in the premixed gas.In process of CH_(4) combustion,the H_(2)O reduces the volume fraction of O,H and OH radicals.At high H_(2)O volume fraction,the effect of radical reaction R38 on promoting CH_(4) combustion is weakened and the flame propagation speed is reduced.