Computational analysis of secondary air flow in a wall-fired power plant.

摘要

In many older fossil power plants operating today, there is insufficient means to assure the proper balancing of the secondary airflows between the individual burners of wall-fired units. This mismatch leads to decreased boiler efficiency and increased emissions. Through the use of a computational fluid dynamics numerical model, a procedure for the balancing of this airflow is developed and tested.; A computational fluid dynamics modeling of a fossil power plant wind box scale model has been constructed using the CFX version 5.4 computer program. This program solves the time averaged Navier Stokes equations with a RNG k-epsilon turbulence model closure. The simulation considers the wind box, burners and associated ductwork of a wall fired fossil power plant. The CFD model results are compared to experimental flow and pressure data taken from a 1/8 th scale model of a wail fired fossil unit. The CFX code is also compared to three other simpler test cases with supporting experimental data.; A numerical procedure for bringing about the equalization of the secondary airflow through the burners of the wind box was developed. This procedure was applied to the simulated burners of the CFD model. Over several iterations the burner secondary air ports were adjusted in position to bring about near equal flow through the burners.