Experimental investigation of temperature distribution and hydrodynamics characterization in a high-temperature gas–solid fluidized bed with sidewall liquid injection

Abstract

Liquid injected into the fluidized bed greatly influences the heat and mass transfer ability and fluidization behavior of the particles. This paper systematically investigated the effects of liquid mass flow rate and superficial gas velocity on temperature distribution, bubble behavior, and pressure fluctuations in a bubbling bed contained liquid injection at the sidewall. The results reveal that an obvious low-temperature zone is observed near the liquid injected nozzle, in which, the superheated vapor is generated and then induces the heat transfer rate in fluidized bed with liquid injection more excellent than that of the conventional fluidized bed. The area of liquid injection zone expands with the injecting liquid flow rate while narrows with superficial gas velocity. Besides, liquid evaporation promotes bubble generation. The increasing liquid amount induces the flow pattern converts to bubbling bed from fixed bed at Ug < Umf. The bubble frequency and size increase with the liquid flow rate and superficial gas velocity. Furthermore, the amplitude of pressure fluctuation is also enhanced with the liquid flow rate. After liquid injecting, a distinct multi-modal distribution is plotted in the power spectral density curve and the low-frequency of peak less than 1 Hz increases with the mass of liquid. The intensity of the peak is enhanced and the bandwidth is broader in incoherent-output power spectral density, indicating more disorder fluidization.