Energy and exergy analysis for waste heat cascade utilization in sinter cooling bed

• A 2-D unsteady model was established to reduce the simulation time.
• The Brinkman–Forchheimer extended Darcy model was adopted for fluid flow.
• The local thermal non-equilibrium model was inserted into CFX for heat transfer.
• The effects of operating parameters on temperature and waste heat were examined.
• Waste heat cascade utilization was analyzed from both energy and exergy aspects.

In the present paper, a numerical study is presented to investigate the cascade utilization of waste heat in sinter cooling bed. With the aid of CFD (computational fluid dynamics), a two-dimensional unsteady mathematical model, which would significantly reduce the computational time, is established to describe three-dimensional steady flow and heat transfer in sinter cooling bed. The Brinkman–Forchheimer extended Darcy model and the LTNE (local thermal non-equilibrium) model are employed to describe flow and heat transfer in sinter cooling bed. And the reliability of this mathematical model is validated with both related simulation and experimental work. And then, numerical simulations are conducted to examine the effects of different operating parameters on the cooling air temperature and waste heat utilization quantity. Furthermore, the waste heat grade and quantity are taken into comprehensive consideration in energy and exergy analysis. The results indicate that, both the quantity and quality of waste heat utilization would be improved by increasing sinter cooling bed height, trolly's moving speed and sinter heat flux. Meanwhile, it is also found that, with different assignments of cooling air flow rate, the quantity and quality of waste heat in sinter cooling bed would not be improved at the same time.