Heat penetration rates of natural convection heating liquids in metal containers

Abstract

Heat penetration (HP) test data have been obtained for water in 13 sizes of metal cans and for 16 fluids with different physical properties in 211 x 400 metal cans. Data were collected until the slowest heating zone was less than 0.1 C° below the heating medium temperature. When conventional HP graphs were plotted, these natural convection heating liquids formed curves instead of straight lines. A straight line was fitted by least squares regression to the data between (T1 - T) values from 40.0 to 4.0, 10.0 to 1.0, 4.0 to 0.4, and 1.0 to 0.2 C° and the f-values determined. The results show that the f-value of fluids that heat by convection increase with heating time, indicating that the true shape of the heat penetration data on a semilogarithmic graph is a curve. Copyright ©, International Association of Milk, Food and Environmental Sanitarians.