Kang Can, Liu Haixia
School of Energy and Power Engineering, Jiangsu University, Zhenjiang 212013, China.
School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, China.
Materials (Basel). 2013 Aug 14;6(8):3514-3529. doi: 10.3390/ma6083514.
Being subjected to a high-pressure abrasive water jet, solid samples will experience an essential variation of both internal stress and physical characteristics, which is closely associated with the kinetic energy attached to the abrasive particles involved in the jet stream. Here, experiments were performed, with particular emphasis being placed on the kinetic energy attenuation and turbulent features in the jet stream. At jet pressure of 260 MPa, mean velocity and root-mean-square (RMS) velocity on two jet-stream sections were acquired by utilizing the phase Doppler anemometry (PDA) technique. A jet-cutting experiment was then carried out with Al-Mg alloy samples being cut by an abrasive water jet. Morphological features and roughness on the cut surface were quantitatively examined through scanning electron microscopy (SEM) and optical profiling techniques. The results indicate that the high-pressure water jet is characterized by remarkably high mean flow velocities and distinct velocity fluctuations. Those irregular pits and grooves on the cut surfaces indicate both the energy attenuation and the development of radial velocity components in the jet stream. When the sample is positioned with different distances from the nozzle outlet, the obtained quantitative surface roughness varies accordingly. A descriptive model highlighting the behaviors of abrasive particles in jet-cutting process is established in light of the experimental results and correlation analysis.
在高压磨料水射流作用下，固体样品的内部应力和物理特性都会发生显著变化，这与射流中磨料颗粒所附着的动能密切相关。在此，进行了实验，特别关注射流中的动能衰减和湍流特性。在260MPa的射流压力下，利用相位多普勒测速仪（PDA）技术获取了两个射流截面的平均速度和均方根（RMS）速度。然后进行了磨料水射流切割Al-Mg合金样品的射流切割实验。通过扫描电子显微镜（SEM）和光学轮廓测量技术对切割表面的形态特征和粗糙度进行了定量检测。结果表明，高压水射流具有非常高的平均流速和明显的速度波动特征。切割表面上那些不规则的凹坑和沟槽既表明了能量衰减，也表明了射流中径向速度分量的发展。当样品与喷嘴出口的距离不同时，所获得的定量表面粗糙度也会相应变化。根据实验结果和相关性分析，建立了一个突出磨料颗粒在射流切割过程中行为的描述模型。
