Thermal fatigue experiment of screw cooling tube under one-sided heating condition

This paper presents the results of thermal fatigue experiments of a cooling tube with a helical triangular fin on its inner cooling surface, namely a screw tube. The screw tube is directly machined in a CuCrZr heat sink bar with slits at its heated side. The thermal fatigue experiments are carried out at 20 and 30 MW/m2. Water leakages from fatigue cracks, found at the slit of the heat sink, occurred at around 4500th and 1400th cycles at 20 and 30 MW/m2, respectively. These results show good agreement with lifetime predictions using Manson–Coffinʹs law based on finite element analyses. Fractographic observations show the fatigue cracks starting from the outer heated surface at the slit region of the cooling channel and propagating toward its inner surface.