A Novel Numerical Simulation Study of Air Leakage in Rotary Air Preheaters Based on Rotor Thermal Deformation

Abstract

Thermal deformation of the rotor is a critical factor leading to radial air leakage in rotary air preheaters. However, previous studies have not comprehensively established the correlation between rotor thermal deformation during thermal operation and radial air leakage. This study addresses this gap by introducing a novel model for calculating radial air leakage, incorporating the thermal deformation of the rotor. To achieve this, we selected a three-section rotary air preheater from a 330 MW coal-fired unit boiler for investigation. This research begins by constructing a heat transfer–structure coupled numerical simulation model using Fluent and ANSYS Workbench. This model is employed to analyze the thermal deformation of the rotor under varying unit power generation loads. This paper meticulously examines the thermal deformation patterns of the rotor in diverse circumstances, explores their impact on air leakages, and provides a comprehensive analysis of air leakage fluctuations in different ducts. The influence of rotor thermal deformation on the local radial leak characteristics is ultimately established. The results indicate that incorporating the impact of preheater thermal deformation into the examination of preheater air leakage enhances the model’s capacity to accurately simulate values of leakage distribution at various cell clearances. This research concludes by offering recommendations for effectively managing hot end radial air leakage in preheater systems, providing valuable insights for the design and adjustment of sealing systems.