Dynamic evaluation of ash deposition behavior and parametric study using an inverse distance weighted interpolation dynamic mesh method

Abstract

Ash deposition is a critical issue concerning the energy utilization and safety operation of heat exchangers. Efficient dynamic evaluation of deposition morphology and reasonable structural parameters contribute to the deposition prediction and the improvement of deposition resistance. In this work, a transient deposition model is established to investigate the dynamic deposition behavior and comprehensive performance. To realize the real-time update of deposition layer morphology, a simple and easy-to-implement dynamic mesh smoothing method based on inverse distance weighted (IDW) interpolation is proposed and then validated by experiments. The effect of the deposition layer dynamic evolution on the particle impact characteristics and the thermal-hydraulic performance of tube bundles is highlighted. In addition, parametric studies are performed on the tube arrangement to obtain the optimal comprehensive performance design. The results show that the angles and velocities of particles impacting the first tube and downstream tubes present a triangular distribution and a butterfly-shaped spatial distribution, respectively. Due to the guidance of the deposition layer on the trajectory of gas and ash particles, the particle impact region on the windward side is more concentrated when using the dynamic mesh model, and the entrainment of small-sized particles is intensified. Besides, the rise in longitudinal spacing significantly exacerbates the deposition and heat transfer deterioration. According to the comprehensive evaluation, the case at SL /D = 2.5 exhibits a higher deposition resistance and heat transfer performance. These results can provide more realistic predictions and indications in practical thermos-equipment design.