Abstract Radiation absorption by preferentially concentrated particles in a turbulent square duct flow is studied experimentally. The particle-laden flow is exposed to near-infrared radiation, and the gas phase temperature statistics are measured along the wall bisector of the duct. It is found that the instantaneous temperature fluctuations are comparable to the overall mean temperature rise. The temperature statistics at the duct centerline and near the wall are qualitatively different. The former reflects preferential concentration in isotropic flows while the latter displays evidence of particle clustering into streamwise elongated streaks. Comparison of the experimental data to a simplified heat transfer model suggests that the Lagrangian evolution of particle clusters and voids, and turbulent mixing in the vicinity of particle clusters, are important. This work was motivated by particle solar receiver technology, but the findings are also relevant to systems where there is localized heat release or mass transfer from disperse particles or droplets. It shows that obtaining Lagrangian histories of particle trajectories is an important next step towards understanding thermal transport phenomena in particle-laden turbulent flows.

中文翻译：

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辐射加热的载有颗粒的湍流方管流中的温度统计

摘要 实验研究了湍流方管流中优先集中粒子对辐射的吸收。载有颗粒的流暴露在近红外辐射下，沿管道壁等分线测量气相温度统计数据。发现瞬时温度波动与整体平均温升相当。风管中心线和靠近壁面的温度统计有质的不同。前者反映了各向同性流动中的优先浓度，而后者显示了粒子聚集成流向细长条纹的证据。将实验数据与简化的传热模型进行比较表明，粒子簇和空隙的拉格朗日演化以及粒子簇附近的湍流混合，是重要的。这项工作的动机是粒子太阳能接收器技术，但这些发现也与分散粒子或液滴局部放热或传质的系统有关。它表明，获得粒子轨迹的拉格朗日历史是理解载有粒子的湍流中的热传输现象的重要下一步。