燃用重整气和煤油的燃烧室燃烧流场数值研究

Numerical Simulation on Combustion Flow Field in Combustor with Reformed Gas and Kerosene

关键词:  双燃料燃烧室  重整气  燃烧流场  数值模拟

Key words:  Dual-fuel combustor  Reformed gas  Combustion flow field  Numerical simulation

摘要:

为考察不同气液燃料对燃烧室性能的影响以及双燃料燃烧室设计时重整气显焓的影响,采用Fluent软件对双燃料燃烧室的燃烧流场进行了数值研究,并将重整气和煤油流场的计算结果进行了对比分析。数值模拟采用了Realizable k-ε湍流模型、PDF燃烧模型、离散相模型和SIMPLE算法。结果表明:燃烧室燃用不同气液燃料时,燃烧室内的回流区结构尺寸大体相同。当重整气和煤油的焓值相同时,重整气燃烧室内的最大轴向回流速度约为煤油燃烧室的5倍,温度降低约300K,火焰变短,出口截面温度分布系数降低7.5%,出口径向温度分布更均匀。进行气液燃料流量换算时,应考虑重整气显焓,否则会导致重整气燃烧室内的最大轴向回流速度增大约12%,火焰拉长,燃烧室出口温度分布系数增大。

Abstract:

In order to investigate the effects of gas/liquid fuel on combustor performance and sensible enthalpy of reformed gas on dual-fuel combustor design,numerical simulation of dual-fuel combustor was performed by Fluent software. A comparative analysis of combustion flow field in combustor with reformed gas and kerosene was carried out. The Realizable k-ε turbulence model,PDF (Probability Density Function) combustion model,discrete phase model and SIMPLE (Semi Implicit Method for Pressure Linked Equations) algorithm were adopted. The simulation results show that the structure size of recirculation zone is almost the same when the combustor is fueled with gas and liquid fuel. When the inlet enthalpy values of the kerosene and reformed gas are same,the maximum back flow velocity in the reformed gas combustor is about 5 times of kerosene combustor,the temperature in reformed gas combustor lowers about 300K,flame length becomes shorter,OTDF (Overall Temperature Distribution Factor) decreases by 7.5% and the combustor outlet radial temperature distribution is more uniform. The sensible enthalpy of reformed gas should be considered when kerosene is replaced by reformed gas. Otherwise,the maximum back flow velocity in reformed gas combustor will increase by about 12%,the flame will become longer and OTDF will become larger.