Computational Model of Complex Heat Flow in the Area of Steel Rectangular Section

The paper presents a computational model used for the analysis of complex heat flow in the area of steel rectangular sections. The model is based on the analysis of heat resistance. A section is considered in the study as a two-phase system of steel and air. Calculation of total section resistance Rst takes into consideration heat conduction in individual phases, thermal radiation between internal section surfaces and free convection of the gaseous phase. Calculations are performed within the temperature range from 20 to 700°C. The results obtained in the study were presented using the replacement thermal conductivity of the section krp. Calculations were performed for three types of sections: 20×40, 40×40 and 60×60 mm with different wall thickness. The values obtained for kef ranged from 3÷13 W/(m·K). The model also allows for the qualitative analysis of heat flow. This analysis is connected with determination of the quantitative fraction of specific heat transfer mechanisms which occur in global heat flow.