No abstract

No abstract

No abstract

The spatial distribution of gas holdup in a stirred tank with a Rushton impeller and i.d. of 380 mm was measured by the fiber optic technique to show the different gas−liquid flow patterns including flooding. The data on loading/flooding transition are found consistent with the general correlation. The experiments were also simulated numerically by the Eulerian−Eulerian approach with the control volume formulation with the k−ε−A p two-phase turbulence model, and different flow patterns in the gas−liquid stirred tank were well demonstrated. It is found that the gas holdup in the impeller discharge stream is underpredicted, but in the broad bulk flow region the results of simulation are in good agreement with the experimental data.

No abstract

A new vision probe based on telecentric photography has been developed for multiphase system measurement. Four outstanding advantages of the probe are as follows: (i) Sharp pictures with little image distortion can be obtained because of the distinctive parallel light paths from the telecentric lens. (ii) The slim probe can be inserted everywhere in large reactors. (iii) Local characteristics such as particle (solid particle or drop or bubble) size, holdup, and interfacial area with one or even more dispersed phases can be measured. (iv) The higher holdup of the dispersed phase is allowed. The robustness of the probe has been tested in a multiphase reactor. Finally, applications in solid−liquid, gas−liquid, and gas−liquid−solid stirred tanks are present respectively to demonstrate the measurements on the particle holdup, bubble size, and particle and bubble size using this vision probe.

No abstract

No abstract