Pressure fluctuation in a gas-solid fluidized bed with coarse granules

Pressure fluctuation in a gas-solid fluidized bed with coarse granules was investigated by using a cold model bed The variance of pressure fluctuation lends to increase with increasing average gas velocity. Bubbles were mainly occurred at the central part of bed under low gas velocity condition while under high gas velocity condition bubbles distributed over the bed cross section. At the minimum velocity of fluidization, the maximum fluctuation in the Power spectral density of the pressure fluctuation was detected to 3.5 x 10(6) Pa-2.s at the frequency of 2.51 Hz of the dominant frequency. As the bed became turbulent the maximum was 12.3 x 10(9) Pa-2.s observed at 3.13Hz of the dominant frequency. The investigation on three dimension reconstructed phase space, correlation dimension and Lyapunov exponent showed that the systems of gas-solid fluidized bed with coarse granules have characteristics of chaos. Its correlation dimension gets to 7.87 and the minimum variable number describing state space is 20 and Lyapunov exponent is positive value and neighbor orbit is fit to rule of exponent dissipation and average dissipation rate is 1.34.