Early start-up of solid oxide fuel cell hybrid systems with ejector cathodic recirculation: experimental results and model verification

For higher concentrations the predictions fall progressively below measured values, leading to order-of-magnitude underestimates for dense beds at close to minimum fluidization conditions. This latter phenomenon might be ascribable to the dominance, under these conditions, of particle–particle interactions. At high particle concentrations, these would give rise to the observed phenomenon of liquid- and gas-fluidized bed apparent viscosities approaching very similar values, and gas pressure having no influence at all.