Thermal-Hydraulic Optimization of Industrial Double-Cavity Blast Furnace Tuyeres with Plant Validation

Blast furnace tuyeres operate under extremely severe thermal conditions and are highly susceptible to localized overheating, which can lead to structural damage and unplanned production interruptions. Improving tuyere cooling performance is therefore essential for maintaining stable blast furnace operation, particularly under intensified thermal loads associated with modern low-carbon ironmaking practices. In this study, a three-dimensional full-scale numerical model of an industrial double-cavity tuyere was developed to investigate the coupled thermal-hydraulic behavior of its cooling system. The effects of key operating and structural parameters, including cooling-water flow rate, inlet temperature, inlet–outlet arrangement, and front-cavity geometry, were systematically analyzed. The results show that temperature non-uniformity in the copper shell is primarily governed by the distribution of cooling-water velocity within the front cavity, leading to severe thermal concentration at the tuyere nose. Increasing the overall flow rate improves bulk heat removal but has limited effectiveness in suppressing local hot spots. Structural optimization that reduces the distance between cooling channels and high-heat-flux regions significantly enhances local heat transfer. A dual-peak counter-current double-cavity configuration further intensifies convective cooling and reduces the maximum shell temperature by up to 129 K compared with the baseline design. Industrial service-life statistics confirm that the optimized structures substantially extend tuyere lifetime, demonstrating the effectiveness of the proposed thermal-hydraulic optimization strategy for practical blast furnace operation.