3-DIMENSIONAL FLUID-FLOW AND HEAT-TRANSFER ANALYSIS OF GRATE BLOCKS IN A WASTE-TO-ENERGY POWER-PLANT

The cause of high operating temperatures experienced by grate blocks i n a waste-to-energy power plant is investigated. A three-dimensional n umerical analysis is performed to assess convection from the grate to the underfire air supply and conduction within the grate. A number of geometric complexities, including variable solid thickness, extended s urfaces, sharp curvatures, and narrow passages, are accounted for via a finite element approach. The grate temperature is found to be very s ensitive to the flow characteristics beneath the grates. Analysis of a modified grate structure was performed, showing a 14% reduction in ma ximum grate temperature.