基于康达效应的海底集矿装置流场与集矿特性试验研究

Experimental investigation on flow field and collecting characteristics of mining device based on Coandǎ effect

海底集矿作为深海矿产资源开发的核心技术之一,直接影响到矿石采集效率和海底沉积物受扰动程度。基于康达效应的水力集矿装置因具有结构简单、可靠性高及对海床扰动小等优点,受到广泛关注。针对基于康达效应的水力集矿头模型进行3种类型的试验研究:1)利用粒子图像测速(PIV)技术测得集矿流场速度分布,试验发现流体质点在靠近凸曲面壁处流速和沿法线速度梯度较大,而远离凸曲面壁处则相反;2)通过高速摄像和图像处理获得球形矿粒运动轨迹和速度,试验发现了不同射流流速下5种典型矿粒运动形态;3)分析了射流流量对矿粒采集率的影响,试验得到了颗粒采集率关于射流流量的变化曲线,并根据变化特征划分为增长区、缓变区和跃升区。研究可为新式集矿装置的优化设计与性能分析提供参考。

Being one of the core technologies of deep-sea mining, the collector near seabed influences the collecting efficiency and seabed disturbance directly. The hydraulic collector based on Coandǎ effect shows satisfactory performance with its simple structure, high reliability and minor disturbance to the seabed, and thus it is paid great attention to. In this study, a hydraulic collector was proposed based on Coandǎ effect and an experiment system was established to examine its performance. The flow field under the collector was recorded using Particle Image Velocimetry(PIV). The characteristics of streamlines and the distribution of velocity were revealed. The results show that the velocity near the curved surface is comparatively large and changes significantly in normal direction, while the velocity far from the curved surface shows the opposite. The motion and trail of nodules under the working collector were captured by a camera. The velocities of nodules under 5 different flow rates of jet were analyzed by image processing technology. The collecting rates under different flows were measured and the relationship appeared to have three stages, i.e. linearly increasing stage, stable stage, and sharply increasing stage. This study is helpful for analyzing the performance and optimizing the design of mining collector.