Gas-fired boiler has received wide attention with the advantages of simple structure and low pollutant emission. In this study, the combustion characteristics and heat flux distribution of gas-fired boiler were investigated numerically under four different loads (30%, 50%, 75%, 100% load). The heat flux distributions of thermal calculation and numerical simulation results have significant difference due to different calculating method. Results show that the temperature in the furnace increases as the increment of boiler loads. The temperature of furnace outlet can reach 1573 K at 100% load. With the increasing of boiler load, the heat flux on each wall increases. The heat flux on rear wall is the highest, whereas the heat flux on front wall is the lowest. The numerical results in this study could provide a reference for optimization of combustion characteristics and design of gas-fired boiler.
Keywords combustion characteristics, heat flux distribution, gas-fired boiler, different loads