HEAT TRANSFER IN A VERTICAL, LIQUID‐FULL SCRAPED‐SURFACE HEAT EXCHANGER. APPLICATION OF THE PENETRATION THEORY AND WILSON PLOTS MODELS

Publisher Website
Google Scholar
Abstract
Heat transfer characteristics of a scraped‐surface heat exchanger (Contherm Model 6 × 2) were evaluated at ultra high temperatures using water and soybean water extracts as model systems. The resistance equation was used to calculate internal (scraped‐side) heat transfer coefficients (hi) from the overall heat transfer coefficient, the wall coefficient and the external (steam‐side) coefficient (calculated from the Nusselt Theory using an iteration procedure). The Penetration Theory of Harriot (1958) predicted hi values quite well at low axial mass flow rates, where laminar flow conditions prevail. However, turbulent axial flow resulted in experimental higreater than predicted by the theory. A correction factor based on Prandtl number suggested by Trommelen et al. (1971) did not improve the prediction. The Wilson Plots method was useful for explicitly accounting for axial and rotational velocity effects, both of which significantly affected heat transfer, especially at high values of either variable.

This publication has 9 references indexed in Scilit: