(601e) Characterization of the Bubble Swarm Trajectory in a Jet Bubbling Reactor

The jet bubbling reactor is a type of gas-liquid reactor with the liquid jet and gas bubbling generator. In the jet bubbling reactor, liquid is transported through a recycling pump and enters the reactor with high speed through a nozzle at the top, leading to a strong shearing effect, and helps to achieve efficient dispersion and mixing between the gas phase and liquid phase. The equipment maintenance cost is significantly reduced through the introduction of liquid jet to replace the traditional agitator by avoiding the vibration of the agitator. However, few reports about the jet bubbling reactor have been published until now. The research reported is mainly related to the mixing and flow patterns in the jet bubbling reactor. However, the bubble motion behavior in the jet bubbling reactor has not been studied yet. It is well-known that the behavior of bubble motion in a gas-liquid reactor plays an important role on the mixing and mass transfer performance of the reactor. Therefore, in this work, by studying the trajectory of bubble swarm to acquaint the behavior of bubble motion in the jet bubbling reactor, it is expected to better understand the liquid phase mixing and gas-liquid mass transfer characteristics in the jet bubbling reactor.

In this work, the trajectory of bubble swarm in the jet bubbling reactor is determined through the BIV technique. The vortex-like motion of bubble swarm is observed when the jet Reynolds number is relatively high. The characteristics of bubble vortices at different times are analyzed, and the bubble vortices oscillate periodically. Finally, an empirical correlation for the oscillating frequency of the bubble vortices in the jet bubbling reactor is built.

Conclusion

The trajectory of bubble swarm in the jet bubbling reactor is studied through the BIV technique. The bubble swarm trajectory is significantly affected by the jet Reynolds number. When the jet Reynolds number is less than 7,000, the bubble swarm trajectory is approximately linear. The vortex-like motion of the bubble swarm is observed when the jet Reynolds number is more than 14,000. At high jet Reynolds number (Re_j>14000), the superficial gas velocity has little effect on the trajectory of bubble swarm. The bubble vortices periodically oscillate in the reactor, and the moving area and oscillating frequency of bubble vortices increase with the increase of the jet Reynolds number. However, there is no significant difference in the oscillating frequency of bubble vortices with the superficial gas velocity changing. When the jet Reynolds number is the same, the oscillating frequency of bubble vortices under gas bubbling conditions is smaller than the flapping frequency of the pure liquid jet without bubbles. An empirical correlation for the oscillating frequency of bubble vortices in the jet bubbling reactor is built according to the simple harmonic vibration theory. Under the experimental conditions of this work, the relative deviation between the experimental and predicted values is within 10%.