Numerical and Experimental Study of Pressure Drop Reduction in a Power Plant Stack

As governmental regulations on the emission of the power industry became more restrictive, many power plants operating today experience severe problems. The fans that handle the flow through the stack, that were originally designed to handle a certain maximum flow rate, are now required to handle even higher flow rates due to the introduction of emission control devices. In this study, computational fluid dynamics (CFD) and experimental studies have been carried out on the scale model of a stack to identify means for pressure drop reduction. The CFD model was constructed using the commercial software CFX-5.6. The model solves the Reynolds averaged Navier-Stokes equation with Shear-Stress turbulence model (SST) and the CFD results are validated by data taken from the scale model. Baffles of different orientation have been installed in the stack under different flow conditions. Both numerical and experimental results confirm that adding baffles can reduce the pressure drop in a stack significantly. Thus, with minimum effort, power plants can keep running the stacks at a higher flow rate.