Studies On Single-Phase Flow Characteristics Of Central-Fuel-Rich Swirl Coal Combustion Burner In A 35 T/h Boiler

With the development of national economy, the demand for electricity is increasing. In order to meet the needs of electricity,the unit capacity boilers are growing in power plant. However, the following problems exist on the operation: the low combustion efficiency and high levels of pollutant emissions. In this case, it is necessary to develop the high efficiency and low NOx swirl combustion technology, which is suitable for China's national conditions and solves the problems existing in the large-scale utility boiler during the pulverized coal combustion process. In this paper, we studies the central-fuel-rich swirl coal combustion burner, which is one of the swirl combustion technologies.In order to carry out boiler burner transformations in a power plant, we study the flow field characteristics of the central-fuel-rich swirl coal combustion burner pilot. Through its single-phase and cold test, we find the optimal structure of pulverized coal combustion in the furnace and use it as the final transformation of the structure. Also, we study the structural parameters and operating parameters on the air flow characteristics of dynamic field of the central-fuel-rich swirl coal combustion burner. Among them, structural parameters include the angle, length and location of the primary air outlet, and the angle and position of the second air outlet, as well as the angle and position of the second air outlet. Moreover, we study the flow field characteristics of the prototype spiral-type swirl burner in the power plant and compare the performance of the two burners. The aerodynamic field results show that the central-fuel-rich swirl coal combustion burner is better than the spiral-type swirl burner.In order to master the ratio of internal and external secondary air volume changed by tangential blade angle, which are not installed the speed devices and in bellows structure, basing on the known optimal structure of it, we get the needed results through the leaves resistance measurement test.According to leaves resistance measurement test results, in order to study the tangential blade angle change on the influence of the flow characteristics outside the burner in bellows structure, we use the hot-wire anemometer to measure the outlet flow of central-fuel-rich swirl coal combustion burner using bellows structure with air distribution to master the flow characteristics, when the tangential blade angle changes. The final results show that it differs the used case, which is that tangential blade angle is changing, but the ratio of the internal and external secondary air volume maintains the same. Therefore, this shows that it can not be ignored that the changing ratio of the internal and external secondary air volume influences the outlet flow of the burner, caused by the tangential blade angle's changing.