Numerical simualtion of a circulating fluidized bed combustor and evaluation of empirical models for estimating solids volume fraction
2021
Yang, Changwon | Jeong, Jaeyong | Kim, Youngdoo | Bang, Byeongryeol | Lee, Uendo
The hydrodynamics of a circulating fluidized bed (CFB) combustor were investigated by conducting experiments on a 100 kWₜₕ CFB test rig and a 3D simulation using a computational particle fluid dynamics numerical scheme. Two empirical models were evaluated for estimating the solids volume fraction of the reactor by comparing the experimental and simulation results. The decay coefficients (a and K for the models) were derived from the simulation results to predict the decay of the axial solids volume fraction in the riser. From the viewpoint of accuracy, the two exponential functions model outperformed the one exponential function model. Empirical models for estimating the core-annulus flow structure in the transport zone were also investigated. Two existing empirical correlations reasonably predicted the wall layer thickness of the test cases except when the superficial velocity was 6.2 m/s. Under such high-velocity conditions, the empirical models overestimated the wall layer thickness by more than 100%.
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