NUMERICAL STUDY OF COMBUSTION PHENOMENON IN AN INDUSTRIAL LOW NOx BURNER

摘要

Reduced emission, higher efficiency, optimum flame shape, better Turn down are the prime design criteria of Industrial burners. Optimizing the Burner design through Experiments calls for increased design Cycle time and cost. This study was aimed at reducing the number of Design of Experiment (DoE) by Numerical modeling multigrid burner system and evaluation of combustion characteristics such as temperature distribution, Flame shape, NOx Emission by varying Primary to Secondary Air split, Degree of Swirl imparted, throat angle. The study comprises of two categories: (a) Isothermal simulation of Air distribution system to ensure uniform distribution to identical burners. (b) Combustion simulation of Fuel oil and air inside furnace. Commercial CFDCode CFX10.0 was used to simulate the reacting flow involving Radiative heat transfer, Pollutant modeling. It was found out that the maintaining optimum ratio of tangential momentum and linear momentum ensures proper mixing of combustion products into core flame region reduces peak flame temperature and thus the max NOx emission. The flame shape was predicted by plotting Isosurface of CO concentration at 1000ppm.The numerical results are compared with the data of an operating unit which showed good agreement in terms of Flame shape (4 m), NOx emission (230 ppm).