Mass and heat transfer intensification at the wall of a square agitated vessel by chemically active semicylindrical turbulence promoters
| Autor: | N. K. Amin, El-Sayed Z. El-Ashtoukhy, Ahmed S. Fathalla, Gomaa H. Sedahmed |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Turbulence 020209 energy Flow (psychology) General Engineering 02 engineering and technology Mechanics Built-in cooler Engineering (General). Civil engineering (General) 01 natural sciences 010305 fluids & plasmas Impeller Semicylindrical turbulence promoters Mass transfer 0103 physical sciences Heat transfer 0202 electrical engineering electronic engineering information engineering Mechanical energy utilization Diffusion current TA1-2040 Immobilized enzyme Mechanical energy Dimensionless quantity |
| Zdroj: | Alexandria Engineering Journal, Vol 60, Iss 5, Pp 4775-4786 (2021) |
| ISSN: | 1110-0168 |
| DOI: | 10.1016/j.aej.2021.03.066 |
| Popis: | Rates of mass and heat transfer at the wall of a square agitated vessel fitted with semicylindrical turbulence promoters were measured using the electrochemical limiting diffusion current technique. Variables studied were promoter diameter, spacing between successive promoters, promoter orientation, impeller speed, and impeller geometry. The data were correlated by empirical dimensionless correlations. The promoters increased both the wall mass transfer coefficients and the volumetric mass transfer coefficients by factors ranging from 1.1 to 1.59 and 1.25 to 2.09, respectively depending on the operating conditions. Vertical turbulence promoters enhanced the rate of mass transfer by 3–29% more than the horizontal promoters. Confirming their economic worth, the turbulence promoters enhanced the mechanical energy utilization of the reactor up to 96%. Power consumption measurements revealed that the 45 ° impeller was more energy-efficient than the 90 ° impeller up to 54%. Besides the novelty of using turbulence promoters in agitated vessels rather than their common use in flow ducts, the present study used chemically active promoters as a catalyst support in conducting diffusion-controlled catalytic reactions at the wall. The novelty of using chemically active promoters qualified the present promoters to outperform the chemically inert promoters in enhancing the mass and heat transfer rates. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|