Predicting particle deposition for flow over a circular cylinder in combustion environments

Particle deposition on heat exchanger tubes is a serious concern in solid fuel combustion and gasification systems, such as power plants and syngas coolers. In order to predict deposition rates, which affect heat transfer efficiencies, several detailed computational fluid dynamic (CFD) models have been developed. However, these models are computationally expensive and cannot be used for quick determination of deposition and/or slagging tendencies. On the other hand, particle impaction efficiency correlations have been developed. While not as accurate as the detailed models, they are easier to use and indicate the impaction of particles on the heat exchanger tubes. However, since deposition and slagging are not just functions of particle impaction rates, but also their sticking propensity, which is related to the particle temperature at impact, the impaction efficiency correlations fail to provide sufficient information. In this work, similar correlations for particle temperature at impact have been developed, based on a non-dimensional parameter that captures the flow and boundary conditions, as well as particle properties. When used alongside the impaction efficiency correlations, the new correlations developed here can provide a reasonable estimate of the deposition and slagging tendencies, at negligible computational expense.