Experimental study on the flow and mixing properties of the radial bias combustion swirl burner

In this paper a new kind of swirl pulverized coal burner, the Radial Bias Combustion swirl (RBC) burner, is introduced. A pulverized coal concentrator is set in the primary air passage, and the primary air is separated into two parts, one has the higher concentration of particles than the another. Since the fuel rich jet owns a stronger flame stability and the overall stoichiometric ratio is the same as an ordinary swirl burner, pulverized coal combustion will have good flame stability and high efficiency. The cold model experiments have been performanced on a one-fifth burner model. A five-hole probe is used to measure the three elements of time-average velocity. For the purpose to investigate the mixing characters of the primary air jet with the secondary air jet, the primary air is heated to several degrees above the other air jets, and the temperature distribution downstream the model is measured. The effects of some flow parameters are studied, which includes the primary air ratio, the non-swirling secondary air ratio. The results show that all of these operating variables have important influence on the flow and mixing properties of swirling jet. The experiments on the cold model have fundamental importance of understanding the combustion performance of the new swirl burner.