Drag coefficient of Solid Recovered Fuels (SRF)

Abstract

The numerical simulation of Solid Recovered Fuels (SRF) co-combustion in pulverised coal power plants requires a flexible particle model, which among other properties should be able to predict the aerodynamic behaviour of the irregular-shaped particles, especially their trajectories along the boiler axis. This will help to provide vital information on whether the SRF particles are entrained in the combustion gases or drop to the boiler bottom. One difficulty encountered in the process is the true value of the drag coefficient ( C D) of the coarse SRF particles. Most of the numerical simulation codes calculate the particle trajectories by integrating the force balance of the particles in which the C D plays an important role. As a result, a true C D of SRF will definitely lead to more realistic results. In this short communication, the authors have taken a practical approach in determining the C D of the SRF. It was found that within the Newton’s law range the C D of the SRF lies between 0.6 and 2.0 with a mean value of 1.5. The results were further validated by correlating the calculated lift velocities of SRF using different C D values and that obtained through experiment.