In order to determine the mechanism of heat transfer to fluidized beds, heat transfer coefficients were measured in the bubble bed, the gas-liquid and the gas-solid fluidized beds. And the rate of mixing measured by a solid tracer technique, and the fluidization quality including bubble frequency and number of density fluctuation per unit time by leak current meter in the gas-solid fluidized bed were correlated.
A semi-theoretical equations to predict heat transfer coefficients in those systems were found, and compared with experimental results.
The equations are as fallwos;
i） Gas-solid fluidized bed
h= 2/π^-1/2·（k_mρ_bmc(u_o/L）)^-1/2 (20)
Developing the model of the packet, relation with heat transfer coefficient, h, and the rate of mixing, Wm, was obtained as follows
h=C_vW_m （19）
ii） Bubble bed and gas-liquid-solid fluidized bed
h = log （μ_Φ/u_o）·(2/π^-1/2)·(k_mρ_mu_o /L)^-1/2 (23)