Heat transfer and pressure drop in a vertical tube with a nodular turbulizer

The paper describes results of experimental investigations of heat transfer and pressure drop in the flow of water and air through a vertical tube with a nodular turbulizer. The turbulizer is made in the form of a cascade of spherical nodes (nodules) placed in the axis of the tube. The investigations exhibit significant intensification of convective heat transfer pronounced in a large increase, up to 2-4 times, in value of coefficient of heat transfer from the inner wall of the tube to water, which takes place at a negligibly small increase of pressure drop. Experiment-based correlations are elaborated for the calculation of the mean heat transfer coefficient and linear pressure drop coefficient for the investigated turbulizer. A calculation model of the complex phenomena accompanying the heat transfer is also presented. The obtained numerical results show a satisfactory agreement with the experimental data. (C) 2008 Elsevier Ltd. All rights reserved.