Coordinate transformation method for heat reallocation in the spiral water-cooled wall temperature calculation

Fireside metal temperature is quite important in the safety evaluation of boiler water-cooled wall. While little literature reported the accurate temperature calculation model for spiral water-cooled wall. This paper proposes a coordinate transformation method for heat reallocation in the spiral water-cooled wall temperature calculation. A computational fluid dynamics (CFD) model based on a 600 MW tangentially coal-fired boiler is used to provide the original heat flux distributions under various boiler loads. The reallocated heat distribution directly maps with the flow path of the spiral water-cooled wall. The combination of the heat reallocation model and thermal-hydraulic model is realized in MATLAB platform. The calculated temperature distributions at the outlet of the spiral water-cooled wall agree well with the in-situ data, and the maximum relative errors under 100% BMCR load and 75% THA load are 2.7% and 3.2%, respectively. The numerical results show that the working fluid flow rates of the divided loops are almost equal and the maximum metal temperatures of the spiral water-cooled wall are 732.1 K, 710.4 K, 760.9 K and 792.9 K under 100% BMCR, 75% THA, 50% THA and 35% BMCR loads, respectively. The local overheating is likely to occur in low boiler load. This model is intended to improve the metal temperature calculation method of the spiral water-cooled wall, which could benefit the safety monitoring of the boiler under variable loads. © 2022 Elsevier Masson SA