Transient heat transfer and bubble dynamics in a pressurized fluidized bed

A flow visualization technique for studying the gas bubble dynamics in a pressurized fluidized bed was developed and used to quantify these dynamics at the surface of a vertical tube submerged in the bed. Transient heat flux measurements were made and correlated with bubble motion. As a result, it is concluded that the heat transfer process is strongly affected by bubble dynamics and is much more complex than any of the generally accepted models can predict. It is also shown that the overall bed operating conditions are the primary driver for local bubble/particle motion around the tube which significantly affects the time-dependent fluctuation in local heat transfer.