Khan Rehan, Wieczorowski Michał, Damjanović Darko, Karim Mohammad Rezaul, Alnaser Ibrahim A
Department of Mechanical Engineering, College of Electrical and Mechanical Engineering, National University of Sciences and Technology, Islamabad 44000, Pakistan.
Faculty of Mechanical Engineering, Institute of Applied Mechanics, Poznan University of Technology, 3 Piotrowo St., 60-965 Poznan, Poland.
Materials (Basel). 2023 Nov 8;16(22):7084. doi: 10.3390/ma16227084.
Several leaks appeared in a mild steel (MS) pipe jet nozzle installed in a direct impact test rig after a few months of operation in erosive flow at the Centre for Erosion-Corrosion Research. The locations of perforation leaks were primarily upstream, but severe wall thinning was also noticed adjacent to the exit section. In this paper, a failure analysis was carried out on the leaking of a pipe jet nozzle, and the results are discussed in detail. The investigation carried out includes visual observation, scanning electron microscopy, 3D scanning, energy-dispersive spectroscopy, and laser profilometry measurements. In addition, numerical simulations based on computational fluid dynamics (CFD) and the discrete phase model (DPM) were conducted to investigate the root cause of the failure of leaks in the pipe jet nozzle. Further CFD-DPM simulations were performed on three different pipe jet designs for liquid-solid flow conditions, and were compared to find an alternative design to prevent the failure of the pipe jet nozzles. It was found that the increase in turbulence along with multiple impacts of particles on the wall generate leaks and cracks in the pipe jet nozzle. Moreover, the CFD-DPM showed a five-fold reduction in the maximum erosion rate; this was observed in the replacement of failed pipes with the proposed alternative nozzle pipe design featuring a chamfer reducer section. The CFD-DPM analysis of all geometric configurations showed that alteration of reducer section design has the greatest impact on erosive wear mitigation.
在腐蚀-磨损研究中心的侵蚀性流体中运行几个月后，安装在直接冲击试验台上的低碳钢管式喷嘴出现了几处泄漏。穿孔泄漏的位置主要在上游，但在出口段附近也发现了严重的管壁变薄。本文对管式喷嘴的泄漏进行了失效分析，并详细讨论了结果。所进行的调查包括目视观察、扫描电子显微镜、三维扫描、能谱分析和激光轮廓测量。此外，基于计算流体动力学（CFD）和离散相模型（DPM）进行了数值模拟，以研究管式喷嘴泄漏失效的根本原因。针对液固流动条件，对三种不同的管式喷嘴设计进行了进一步的CFD-DPM模拟，并进行比较以找到一种替代设计来防止管式喷嘴失效。研究发现，湍流的增加以及颗粒对壁面的多次冲击会在管式喷嘴中产生泄漏和裂纹。此外，CFD-DPM显示最大侵蚀速率降低了五倍；在用具有倒角变径段的建议替代喷嘴管设计替换失效管道时观察到了这一点。对所有几何构型的CFD-DPM分析表明，变径段设计的改变对减轻侵蚀磨损的影响最大。
