Heat transfer in aggregative and particulate liquid-fluidized beds

✍ Scribed by Rutton D. Patel; John M. Simpson

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 861 KB
• Volume: 32
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(77)80197-8

✦ Synopsis

Wall-to-bed heat transfer m hquld fluldized beds, particulately and aggregatively flmdued, was studied Glass particles fluuhzed with water gave particulate flmdlzation and lead particles with water gave aggregahve flmduation Local heat transfer coefficients and bed temperature profiles were measured Heat transfer coefficients were found to be strongly dependent on particle size and porosity and Increased with mcreasmg par&le sme, but were independent of the he&t of the heater surface from the gnd Any vanatlons m local bed propeties, such as porosity do not atkct wall-to-bed heat transfer The heat transfer coefficients show a charactenstlc maxImum at porosltles near 0 '7 for both systems Bed temperature profiles deviate conslderably from open-pipe values A two-resistance model for the heat transfer resistance agrees well with the data Bed resistance IS modeled by a radtal eddy dtiuslvlty. whtch m&cates the mlxmg effectiveness m the core of the bed Glass beds (pticulate) show a maximum mlxmg effectiveness at porosities near 0 7 and the nuxmg effectiveness Increases with particle diameter Lead beds (agpregahve) show two maxuna m nuxmg effectiveness, the first between porosltles of 0 5 and 0 6, and the second between porosifies of 0 7 and 0 8 Muring IS greatest at an mtermedmte particle size m the case of lead beds In both systems the fraction of the total resistance m the bed core Increases as porosity decreases towards packed bed con&tions