A particle deposition model considering particle size distribution based on the Eulerian approach

Abstract

The problem of ash deposition on heat exchange surfaces is one of the main causes hindering the safe and efficient operation of conventional boilers. Hence, looking into the particle deposition characteristics on heat transfer surfaces as well as the formation process and the deposition mechanism is essential. In this study, a particle deposition model considering the particle size distribution based on the Eulerian approach is presented to predict the dynamic deposition process of multi-sized particles on the surfaces of heat exchange tubes. The model harnesses the advantages of the Eulerian approach and takes into account the particle size distribution as well as the interaction between them. By coupling computational fluid dynamics (CFD) analysis with the population balance model, and the embedding user-defined function code with the deposition model, the deposition characteristics of the multi-sized particles are predicted. It is established that the simulation findings of this model, as opposed to models for average-sized particles, are in greater accord with the experimental data by comparing the model predictions against published experimental results, with the average relative deviations are reduced by 9.28%, 8.11%, and 7.14%, respectively. The weighted average of the latter three dimensionless deposition velocities of multi-sized particles are all greater than those of average-sized particles. Moreover, the net deposition mass of multi-sized particles is 9.34% higher than that of average-sized particles.