Abstract Highly viscous flow in a large-scale pressure-swirl atomizer is studied by (1) 3d scale-resolving large-eddy simulations and volume-of-fluid method, and (2) experiments based on laser-Doppler anemometry, imaging techniques and pressure measurements. Here, a low Reynolds number regime (600 ≤ Re ≤ 910) is investigated by varying the mass flow rate of the water-glycerol mixture. The aim of the study is to perform a comprehensive comparison between the simulations and experiments at a parameter range and nozzle geometry relevant for biomass based fuels. We report the inner-nozzle velocity profiles noting good agreement for mean velocities inside the swirl chamber between the simulations and the experiments. Consistent with the earlier work ( Laurila et al., 2019 ), the simulations indicate the flow mode to be laminar with weak or non-existent gaseous core inside the swirl chamber. As revealed by both approaches, liquid film shapes after the nozzle discharge orifice are qualitatively similar, of hollow cone type, and highly unstable. Both approaches indicate linear scaling of the liquid film velocity with the inlet Reynolds number and discharge coefficients to be in the range 0.57–0.64. The experimentally measured mean opening angles are reported to be 45–62∘, while the numerical counterparts show reasonable correspondence with the experiments. The results demonstrate the predictive ability of the present numerical method in swirl injector analysis.

中文翻译：

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粘性流体涡流喷嘴的计算与实验研究

摘要 通过 (1) 3d 尺度分辨大涡模拟和流体体积法, (2) 基于激光多普勒风速测量、成像技术和技术的实验研究了大型压力旋流雾化器中的高粘性流动。压力测量。在这里，通过改变水-甘油混合物的质量流速来研究低雷诺数制度 (600 ≤ Re ≤ 910)。该研究的目的是在与基于生物质的燃料相关的参数范围和喷嘴几何形状下对模拟和实验进行全面比较。我们报告了内部喷嘴速度分布，注意到模拟和实验之间涡流室内的平均速度具有良好的一致性。与早期的工作一致（Laurila et al., 2019），模拟表明流动模式是层流的，在涡流室内有微弱或不存在的气态核心。两种方法都表明，喷嘴排放孔后的液膜形状在性质上相似，为空心锥型，极不稳定。两种方法都表明液膜速度的线性标度，入口雷诺数和流量系数在 0.57-0.64 的范围内。据报道，实验测量的平均开口角为 45-62∘，而数值对应物与实验显示出合理的对应关系。结果证明了本数值方法在旋流喷射器分析中的预测能力。空心锥型，极不稳定。两种方法都表明液膜速度的线性标度，入口雷诺数和流量系数在 0.57-0.64 的范围内。据报道，实验测量的平均开口角为 45-62∘，而数值对应物与实验显示出合理的对应关系。结果证明了本数值方法在旋流喷射器分析中的预测能力。空心锥型，极不稳定。两种方法都表明液膜速度的线性标度，入口雷诺数和流量系数在 0.57-0.64 的范围内。据报道，实验测量的平均开口角为 45-62∘，而数值对应物与实验显示出合理的对应关系。结果证明了本数值方法在旋流喷射器分析中的预测能力。