Effect of emulsion fluidization state on the fluctuations in gas and particle velocities inside the plume of a gas jet injected into a fluidized bed

Studies concerning the influence of fluidizing air on the gas–solid flow that occurs when a high-speed jet is injected into a fluidized bed have been limited to the measurement and analysis of mean velocity profiles. This study presents Laser Doppler Velocimetry (LDV) measurements and analysis of the change in the fluctuations of both gas and particle phase velocities inside the jet plume region with change in the fluidized state of the emulsion. It is observed that there is a small decrease in the fluctuating intensity in both phases upon increasing the fluidization velocity from 0 to 0.7 times minimum fluidization. However, increasing the fluidization rate (distributor gas flow rate) beyond minimum fluidization significantly increases the intensity of velocity fluctuations in both phases. A qualitative explanation based on the coupling that occurs between the two phases through the mean flow variables is proposed to explain the observations.