Time dependent hydrodynamics in multiphase reactors

✍ Scribed by D.C. Dankworth; I.G. Kevrekidis; S. Sundaresan

• Book ID: 103008689
• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 802 KB
• Volume: 45
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(90)80101-j

✦ Synopsis

Time dependent flow often occurs in multiphase reactors. Examples of practical interest include pulsing flow in the case of cocurrent downflow of gas and liquid through a packed column, and voidage fluctuations in fluid-solid flows. In these examples, the local mean volume fractions and velocities of each phase can bc described by similar volume-averaged macroscopic models. In one dimension, fully developed flow takes the form of periodic waves travelling at constant speed through the bed. The shape of waves having observable wavelength is dictated by proximity to a heteroclinic connection in the travelling wave frame between two unstable uniform solutions having the same total volumetric flux. Consequently, the properties of the fully developed travelling waves can be determined by locating the two connected fixed points. A concise operating diagram can be constructed for the gas-liquid-packing system in terms of the externally applied fluxes of each phase. Qualitatively different solutions are obtained in each region of the operating diagram. Application of these methods to models for fluid-solid flow is also discussed.