Predicting Dust Erosion in a Counter-Rotating Fan

Counter-rotating fans (CRFs) become an attractive solution for the ventilation of tunnels and mines, but operate under particulate flows and suffer from serious erosion. This study aims to provide insights into the dynamics of ingested dust particles and erosion development. The computations used an in-house Lagrangian particle tracking code that implements the random walk algorithm and probabilistic models for the particles release positions, sizes, and rebound factors. The finite element method tracks particles through the mesh elements and provides exact the impacts and the conditions required to evaluate the local erosion rates. The pollutant is the Saharan dust, with finer-sized particles ranging from 0.1 to 100 microns, and concentration between 0.1–0.5 mg/m3, that was extended to 1–3 mg/m3 to simulate a mine atmosphere. As a result, the front rotor (FR) exhibits impacts of high frequency, and thus erosion develops along the leading edge (LE) and extends over a large band from the blade suction side (SS) and upward to two-thirds of the blade pressure side (PS) and along the blade tip. On the other hand, the rear rotor (RR) exhibits similar patterns of erosion where the LE and the fore of the SS are more eroded, as well as the PS, which depicts a larger area of erosion. It seems that the erosion rate densities of RR are practically doubled, except for the upper region from the TE. The present results help to monitor the in-service lifetime of CRFs and select coatings to resist erosion.