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Title: Heat transfer and power consumption in an agitated vessel
Author: Nezhati, K.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1983
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This thesis presents the results of an investigation of heat transfer in a Jacketted agitated vessel, using Newtonian and non-Newtonian fluids (pseudoplastic and dilatant). Heating and cooling data were taken for these liquids for different geometries of the paddle (height, width, and diameter) and for double paddles, a pitched-bladed paddle, and a double pitched-bladed paddle. All the above data were taken for the baffled and unbaffled condition. Impeller power consumption was measured using an electro-mechanical method. The average shear-rate in the vessel for the non-Newtonian liquids was calculated by applying the method presented by Parlushenko, which considers flow behaviour index, agitator speed and agitator diameter. The results were correlated using three methods: 1. Conventional dimensional analysis; 2. By application of the theory of local isotropic turbulence; 3. By considering the mixing of the boundary layer flow with the bulk liquid. The results were correlated for one geometry of the paddle impeller using dimensionless numbers. A method of statistical analysis was used to investigate the difference between the measured accumulated heat and the heat transfer calculated from the theory of boundary layer mixing. Comparison between the three methods showed that the first method was the most accurate for deriving the heat transfer coefficient. Comparison of plots of power input versus heat transfer coefficient for the impellers used, showed that the double-paddle impeller (d = 229 mm) was more efficient for heat transfer. In general, the standard paddle impellers (single and double) were more effective than the pitched-bladed paddle for heat transfer.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available