External Heat Transfer Coefficient in Agitated Vessels Using a Radial Impeller and Vertical Tube Baffles
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- 作者：Vitor da Silva Rosa ; Marlene Silva de Moraes ; Juliana T贸fano de Campos Leite Toneli ; Deovaldo de Moraes J煤nior
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2014
- 出版时间：September 3, 2014
- 年：2014
- 卷：53
- 期：35
- 页码：13797-13803
- 全文大小：402K
- ISSN：1520-5045
文摘
There are several correlations used to predict the external heat transfer coefficient in tanks equipped with vertical tube baffles in batch operations, but little information concerning the external heat transfer coefficient in steady state operations. The objective of the present article is to experimentally determine a correlation of the external heat transfer coefficient based on the model proposed by Sieder and Tate (Ind. Eng. Chem. 1936, 1429鈥?435) in a steady flow rate in a vessel equipped with a radial impeller, turbine type, with six flat blades. The study was carried out in a 50 dm3 working capacity acrylic vessel, fitted with vertical tube baffles made of copper, in which water and sucrose solutions at mass concentrations of 20% and 50% were heated. Heating temperatures varied from 28 to 45 掳C, whereas the rotations varied from 90 to 330 rpm. From the Nusselt, Reynolds, and Prandtl similarity parameters, a correlation was obtained which yielded excellent results of the observed data鈥揳 maximum deviation of 21% between the observed and predicted data for the external heat transfer coefficient. In addition, one could also observe that the radial impeller raises the heat transfer to as much as 70% compared to the axial impeller for the same study conditions.