Abstract The present work aims for the isolated investigation of the influence of system pressure on spray quality of twin-fluid atomizers. An approach of pressure adapted nozzles was applied, allowing for constant mass flows, gas-to-liquid ratio as well as fluid velocities at the nozzle orifice independent of system pressure. Two Newtonian liquids featuring viscosities of 1 and 100 mPa · s were used, varying the system pressure from 1 to 16 bar for gas velocities of 60, 80 and 100 m · s − 1 . A phase doppler analyzer was applied for measurement of resulting drop size and velocity. Primary breakup morphology was detected by a high-speed camera. Two regions with different dependencies of spray quality on system pressure were identified. Applying pressure adapted nozzles while increasing system pressure, first results in a decrease of droplet size followed by an increase. A maximum of the dynamic pressure of the gas phase was determined at minimum droplet size, which is explained based on the theory of a free jet. The observations are underlined by images of the high-speed camera. Here, a change in breakup morphology from fiber type to a mixture of fiber type and non-axisymmetric Rayleigh type breakup at high system pressure was observed.

中文翻译：

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系统压力对产生的喷雾质量和射流破碎应用压力适应双流体喷嘴影响的实验研究

摘要 目前的工作旨在独立研究系统压力对双流体雾化器喷雾质量的影响。应用了压力适应喷嘴的​​方法，允许恒定的质量流量、气液比以及喷嘴孔口处的流体速度与系统压力无关。使用了两种粘度分别为 1 和 100 mPa·s 的牛顿液体，对于 60、80 和 100 m·s - 1 的气体速度，系统压力从 1 巴变化到 16 巴。相位多普勒分析仪用于测量产生的液滴尺寸和速度。初级破碎形态由高速相机检测。确定了喷雾质量对系统压力具有不同依赖性的两个区域。在增加系统压力的同时应用压力适应喷嘴，首先导致液滴尺寸减小，然后增加。在最小液滴尺寸时确定气相的最大动态压力，这是基于自由射流理论解释的。高速摄像机的图像强调了观察结果。在这里，观察到在高系统压力下从纤维类型到纤维类型和非轴对称瑞利类型的混合物的破裂形态的变化。