Simulation analysis of backflow prevention design and optimization of power station exhaust system

In diesel generator systems, the exhaust duct has significant impacts on the power generation performance and exhaust safety. Varied exhaust duct design schemes often lead to different patterns of flue gas flow, and high-velocity wind will exert a shear effect on the system, which impedes normal discharge of flue gas and results in downdraft. In response to this problem, the ANASYS FLUENT software is employed in this study to simulate the gas flow in exhaust duct of diesel generator units in a power station to identify the optimal stack structure. Specifically, this study examines the pressure distribution, gas flow velocity distribution, and mass fraction of the gas at the stack outlet under different operating conditions—three stack design schemes and two flue gas mass flow rates at Beaufort Force 9 winds. Moreover, in relation to the pressure at the stack outlet and the gas velocities, the downdraft under different operating conditions is analyzed, and the optimal stack structure is identified for the diesel generator units in the studied power station that takes into account the flow resistance and prevent downdraft.