In an experimental study the effects of varied oxygen concentrations in the oxidizer gas on resulting flow fields, combustion products and general behavior of pulverized coal swirl flames under oxy-fuel conditions have been investigated. Experiments were carried out in a small scale down-fired cylindrical combustion chamber equipped with an annular swirl burner. Studied flames had a constant power output of 40 kW_th and O₂/CO₂ oxidizer gas mixtures with O₂ concentrations ranging from 23 to 33 vol%. Detailed two-dimensional flow field measurements are obtained from laser Doppler anemometry (LDA). Velocity profiles (Mean and RMS) have been obtained for all conditions investigated and serve as basis for identification of flow field characteristics. Velocity RMS values are provided as supplementary material. To complement flow field measurements, in-flame gas composition measurements were also conducted using a sampling probe combined with infrared gas absorption analysis via Fourier-transform infrared (FTIR) spectrometry. The results obtained show increased velocities, particularly along the main vortex for flames with increased oxygen contents, while lower velocities are found to occur inside the recirculation regions. The opposite occurs with lower O₂ concentrations, showing significantly reduced velocities in the main vortex, but stronger recirculation than the high oxygen counterparts. This effect is attributed to a modification of the swirl level introduced by the expansion of product gases. Measured NO and CO in-flame concentrations showed significant variations under different O₂ concentrations in the oxidizer.

在一项实验研究中，研究了氧化剂气体中不同的氧气浓度对在氧气-燃料条件下产生的流场，燃烧产物和粉煤旋流火焰的一般行为的影响。在装有环形涡流燃烧器的小尺寸向下燃烧的圆柱形燃烧室中进行实验。研究火焰的恒定功率输出为40 kW _th，O ₂ / CO ₂氧化剂与O _2的混合气体浓度范围从23到33 vol％。详细的二维流场测量是从激光多普勒风速仪（LDA）获得的。速度曲线（平均值和均方根值）已针对所有研究条件获得，并作为识别流场特性的基础。速度RMS值作为补充材料提供。为了补充流场测量，还使用采样探针与通过傅里叶变换红外（FTIR）光谱进行红外气体吸收分析相结合的方法进行了火焰中气体成分的测量。所获得的结果表明，速度增加了，特别是对于含氧量增加的火焰，沿着主涡流的速度增加了，而发现较低的速度发生在再循环区域内。较低的O _2则相反浓度，显示出主旋涡的速度显着降低，但比高氧对应物的再循环更强。该效果归因于由产物气体的膨胀引入的涡旋水平的改变。在氧化剂中不同的O ₂浓度下，测得的NO和CO燃烧浓度显示出显着变化。