hydrodynamics of a gas-solid fluidized bed at elevated temperatures using the radioactive particle tracking technique

effect of temperature on hydrodynamics of bubbling gas-solid fluidized beds was investigated.  experiments were carried out in the range of 25-600 ºc and different superficial gas velocities in the range of 0.17-0.78 m/s with sand particles. time-position trajectory of particles was obtained by radioactive particle tracking technique. these data were used for determination of mean velocities of upward-moving (including bubble wake and ascending clusters) and downward-moving (descending clusters) particles. it was found that the upward velocity increases by increasing temperature up to 300 ºc, however, it decreases by further increase in temperature. due to the wall effect, there is no significant change in the mean velocity of downward-moving clusters. the change in hydrodynamic parameters with temperature can be a consequence of changing physical properties of the bed which have been represented by reynolds number in this study.