Instability waves and the origin of bubbles in fluidized beds: Part 1: Experiments

Statistically significant measurements of the propagation properties of instability waves in a two-dimensional liquid fluidized bed are reported. Visual and quantitave measurements show that although the waves experience an initially exponential growth in amplitude, the ultimate state of motion exhibited is that of the complicated formation and destruction of cylindrical bubble-like structures. Expected values of their amplitude, frequency, and velocity are measured, and preliminary scaling laws are proposed. The implication is that bubbles in gas-fluidized beds are a result of the same instability of the state of uniform fluidization.