ABSTRACT International standards for cooling curve analysis use flat-end cylindrical quench probes; however, changing the probe end may lead to a better performance. To assess the effect of probe geometry on the flow near the solid–liquid interface, computational fluid dynamics (CFD) simulations of velocity and pressure fields under low-temperature conditions were carried out. To validate the mathematical model, tests were performed in a laboratory-scale device to visualise streamlines around the probe. The variables studied were probe end geometry (flat-end, hemispherical-end, and conical-end) and water free-stream velocity. From the simulations, it was observed that the flat-end cylindrical probe distorts the flow pattern near the probe end. This distortion agrees with the computed dynamic pressure field, and it is attributed to the decreasing velocity in that region. Streamlines around the conical-end and the hemispherical-end probes suggests more favourable hydrodynamic conditions for cooling curve tests. The measured cooling curves were more reproducible when using the conical-end probe, which may be explained based on variability in the collapse of the vapour film and the advancing of the wetting front. Videos taken during the quench tests showed different initial vapour film geometry, depending on the probe geometry, that can be explained using the computed streamlines.

中文翻译：

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探针几何形状对实验室规模淬火探针附近流体流动的影响

摘要 冷却曲线分析的国际标准使用平端圆柱形淬火探头；但是，改变探头末端可能会带来更好的性能。为了评估探针几何形状对固液界面附近流动的影响，进行了低温条件下速度和压力场的计算流体动力学 (CFD) 模拟。为了验证数学模型，在实验室规模的设备中进行了测试，以可视化探头周围的流线。研究的变量是探头端部几何形状（平端、半球形端和锥形端）和水自由流速度。从模拟中，观察到平端圆柱形探头扭曲了探头端附近的流动模式。这种失真与计算出的动态压力场一致，这归因于该区域的速度下降。锥形端和半球端探头周围的流线表明冷却曲线测试更有利的流体动力学条件。当使用锥形端探头时，测得的冷却曲线更具有重现性，这可能是基于蒸气膜塌陷和润湿前沿推进的可变性来解释的。在淬火测试期间拍摄的视频显示了不同的初始蒸汽膜几何形状，这取决于探头几何形状，可以使用计算的流线进行解释。这可以根据蒸气膜塌陷和润湿前沿的推进的可变性来解释。在淬火测试期间拍摄的视频显示了不同的初始蒸汽膜几何形状，这取决于探头几何形状，可以使用计算的流线进行解释。这可以根据蒸气膜塌陷和润湿前沿的推进的可变性来解释。在淬火测试期间拍摄的视频显示了不同的初始蒸汽膜几何形状，这取决于探头几何形状，可以使用计算的流线进行解释。