Heat transfer and power measurements in stirred tanks using heat flow calorimetry

✍ Scribed by J.R. Bourne; M. Buerli; W. Regenass

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 654 KB
• Volume: 36
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(81)85014-2

✦ Synopsis

A new method is presented for determining the power consumption of an impeller in a stirred tank as well as the inside film heat transfer coefficient. It uses a bench-scale heat flow calorimeter in which the jacket temperature is rapidly and automatically adjusted to maintain isothermal conditions in the calorimeter. Five working fluids were used. Power consumptions for turbine, Pfaudler and anchor impellers agree well with literature values. Heat transfer coefficients for anchor and gate impellers measured in the calorimeter as well as in 2.5 and 5.4m' tanks were fitted with consistent Nu-Pr-Re equations. The dimensionless correlations for anchor and Pfaudler impellers determined whh the calorimeter were consistent with literature correlations found from other equipment. The heat transfer values for the turbine, although agreeing with some previous investigations, were lower than those found by others. Heat transfer coefficients were also expressed as a function of the physical properties of the fluid and the power consumption per unit volume. irrespective of impeller type.

A plant-scale heat transfer coefficient can be estimated rapidly and accurately from a few runs in a bench-scale heal flow calorimeter, without having to determine the physical properties of the fluid mixture.