Investigation of deposition characteristics on tube-bundle heat exchanger with an improved ash particle model

The deposition of fly ash in the tube-bundle heat exchanger has become an urgent problem that must be resolved. During the deposition process, the fly ash particles will alter the physical properties and geometry of the heat exchange surface. A random function model combined with the dynamic mesh method is proposed to improve the existing particle deposition model. The effects of various flow velocities and particle sizes on particle deposition are analyzed. The results indicated that the total deposition mass of large particles decreases and the small particles increases as the flow velocity increases. With increasing particle size at the same flow velocity, the total particle deposition mass increases first and then decreases for in-line tube bundles. Local analysis indicates that the initial deposition occurs primarily on the windward side of the tube, with a greater number of particles deposited on the upstream tube bundles than on the downstream tube bundles.