Numerical investigation of heat transfer in the clinker cooling process of grate cooler

The grate cooler is the key device for clinker cooling; internal heat transfer between the cooling gas and the clinker affects not only the clinker quality but also the efficiency of heat recovery. In this study, an unsteady numerical calculation model was developed, incorporating the porous media model and the local thermal non-equilibrium model, to describe the flow and heat transfer processes in a grate cooler. The reliability of the calculation model was verified using thermal measurement data. Simulations were carried out and the effects of the cooling gas mass flow rate on the distribution of clinker temperature and exhaust gas temperature were assessed. The results show that both the gas and clinker temperatures decreased along the lengthwise direction of the grate cooler and increased along the direction of the clinker layer thickness. The cooling effect of the clinker increased with an increase in the cooling gas mass flow rate. However, the magnitude of this increase weakened with an increase in air volume. Recirculating low-temperature air to the front chamber can improve the heat recovery efficiency of a grate cooler while ensuring effective clinker cooling.