Analysis of the influence of thermal contact conduction on the intensity of heat flow in a bundle of round steel bars

Abstract

The article analyzes the impact of contact conduction on the intensity of heat flow in a bundle of steel round bars. This issue is related to the optimization of the heat treatment of the bars, as contact conduction is a key mechanism in the heating process of the considered charge. A proprietary computational model, based on the analysis of thermal resistances, was used for the analysis. To quantify heat flow intensity in the bar bundle, the concept of effective thermal conductivity was utilized. The impact of contact conduction on the phenomenon under consideration was expressed using a parameter called the multiplication of effective thermal conductivity (\({M}_{ ETC})\), defined by Eq. (36). Calculations were conducted across a temperature range of 25–800 °C, considering variables such as bar diameters (10, 20, and 30 mm), bundle porosity, and type of gas (air and hydrogen). Results indicate that temperature has the greatest influence on the course of the analyzed phenomenon, as this parameter increases, the influence of contact conduction decreases rapidly. Across the entire temperature range, contact conduction increases heat transfer intensity by approximately: four times (for air) and twice (for hydrogen).