片状微细颗粒高速撞击壁面的反弹特性研究

Researching on the rebound characteristics of fine flaky particles impinging solid wall with high velocity is the key technical foundation to solve particle erosion and deposition problem of key components in power equipment. In the project, a vacuum acceleration method is employed to eliminate the effect of air flow on the particle rebound characteristics in the near-wall region. Based on the long-distance microscopy and shadowgraph, a novel idea is presented to measure the shape, size, orientation, translational velocity, angular velocity, flow field of flaky particles synchronously. Through statistical analysis on the extensive experimental results, the physical nature of particle rebound-rotation behavior, as well as the critical parameter feature and dynamic mechanism of particle rebound direction of centralization and decentralization is revealed. A universal particle rebound model is established, and the basic theory and application criteria of fine flaky particles motion behavior in near wall region is perfected. These studies will provide a reliable technical basis for theoretical analysis of phase flow, particle erosion damage control and service life prediction of equipment.

研究片状微细颗粒高速撞击固体壁面的反弹特性是解决动力装备关键部件颗粒冲蚀和沉积的关键技术基础。本项目通过真空加速方法消除近壁区气流对颗粒反弹测量的影响，并基于阴影长距离显微成像技术，提出一种同步测量片状颗粒的形状、尺寸、三维平移和旋转速度及其流场的新方法。通过大量试验研究和统计分析，揭示颗粒反弹-旋转的物理本质以及反弹方向集中与分散的临界参数特征和动力学机制，建立具有普适性的颗粒反弹模型，完善片状微细颗粒近壁运动行为的基本理论和应用准则。这些研究将为气固两相流理论分析、颗粒冲蚀破坏控制和设备服役寿命预测提供可靠的技术依据。

本项目以化石燃料、氧化皮等片状颗粒对锅炉换热管、蒸汽流道和气力输送管等装备部件的冲蚀问题为研究背景，以20~500μm片状固体颗粒与固体壁面的撞击反弹过程为研究对象，采用真空加速方法和PIV可视化测量技术，设计搭建了一套可实现片状颗粒运动行为观测、追踪的试验测试系统。基于该实验系统，开展了不同工况下片状颗粒高速撞击壁面的反弹特性实验研究。通过对大量试验结果的统计分析，结合对试验后靶材表面的微观形貌和力学性能测试，获得了颗粒撞击速度、撞击角度、颗粒尺寸、靶材硬度等参数对片状微细颗粒反弹特性的影响规律，揭示了上述参数对片状颗粒反弹特性的影响机制。在对实验结果总结分析的基础上，通过多元拟合方法建立了片状颗粒反弹模型。通过将数值模拟应用结果与动力装备实际冲蚀位置和分布相比较，初步验证了模型的可靠性和适用范围。研究结果为气固两相流理论分析、颗粒冲蚀破坏控制和动力设备服役寿命预测提供了的基础数据。项目执行期间，共撰写学术论文5篇，SC1源刊论文2篇，EI论文3篇，申请国家发明专利2项，授权实用新型专利2项。