Heat transfer and thermal deformation analyses of a copper stave used in the belly and lower shaft area of a blast furnace

• Previous models only describe the temperature and thermal stress distribution of copper stave, and rather less effort have been invested to understand the thermal deformation behavior of copper stave. However, the thermal deformation behaviors have an important influence on the campaign life of copper stave.
• A 3D mathematical model considered the effect of constraint of the shell is established in this paper, and there is a good agreement between calculated and measured temperature.
• Previous work neglects the effects of copper stave thickness and bolts position on the thermal deformation behaviors in copper stave. The quantitative relation between copper stave thickness and the thermal deformation behaviors in copper stave is very important for design of copper stave.
• A completed quantitative analysis of thermal and deformational behavior in copper stave has not yet been performed.
• The quantitative relation between gas temperature, water velocity, copper stave thickness, bolt position and thermal deformation, stress distribution of copper stave at the root of the pipe can provide an understand of the pipe weld failure problem.

This article describes a mathematical model to predict the temperature, thermal deformation and stress in a copper stave with no accretion layer during operation. The effects of gas temperature, cooling water velocity, copper stave thickness and bolt position on temperature, thermal deformation and stress of copper stave are investigated. The results show that a maximum temperature, about 422.5 K (149.5 °C), is found just near the top or bottom of the copper stave hot face. Copper stave deforms into the typical parabolic arc. Decreasing gas temperature can decrease the temperature, thermal deformation and stress, and decreasing the distance between the bolts and top or bottom border of copper stave are available in decreasing the copper stave thermal deformation, therefore improving the copper stave life. Increasing copper stave thickness can increase the temperature and thermal deformation for smaller copper stave thickness, while the thermal deformation in copper stave decreases with copper stave thickness increase for higher copper stave thickness. Water velocity has little effect on temperature and thermal deformation in copper stave, while much effect on the thermal stress around the root of the pipe.