Uncertainty quantification of an effective heat transfer coefficient within a numerical model of a bubbling fluidized bed with immersed horizontal tubes
Moulder, Christopher James
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This study investigates sources of steady state computational uncertainty in an effective heat transfer coefficient (HTC) within a non-reacting bubbling fluidized bed with immersed horizontal heat-conducting tubes. The methodical evaluation of this variation, or Uncertainty Quantification (UQ), is a critical step in the experimental analysis process, and is particularly important when the values of input physical parameters are unknown or experimental data is sparse. While the concept applies broadly to all studies, this application investigates a 2D unit cell analogue of a bubbling fluidized bed designed for large-scale carbon capture applications. Without adequate characterization of simulation uncertainties in the HTC, bed operating characteristics, including the thermal efficiency, carbon capture efficiency, and sorbent half-life cannot be well understood. We focus on three primary parameters, solid-solid coefficient of restitution, solid-wall coefficient of restitution, and turbulence model, and consider how their influences vary at different bed solid fractions. This is accomplished via sensitivity analysis and the Bayesian Spline Smoothing (BSS) Analysis of Variance (ANOVA) framework. Results indicate that uncertainties approach 20% at high gas fractions, with the turbulence model accounting for 80% of this variation and the solid-solid coefficient of restitution accounting for the additional 20%.