Abstract: Pulverized coal high-efficiency and low-nitrogen combustion technology is a hot spot in the field of coal utilization.As a core equipment of the pulverized coal boiler,it is very important to study the design principle and technology of pulverized coal burner suitable for multiple coal types and wide load conditions.The mechanism of reverse jet steady combustion is mostly applied in the field of aero-engines and gas turbines,and rarely used in the field of pulverized coal combustion.Therefore,the studies on the influence of the pre-combustion chamber on the flowfield characteristics of the swirl burner are available,however,there are few studies about the influence on the flow field of the reverse-jet swirl burner.In this paper,In order to explore the influence of precombustion chamber on the flow field characteristics of a reverse swirl pulverized coal burner,and taking a 20 t/h reverse jet swirling burner as a prototype,a cold burner model was built based on the isothermal modeling principle.Then,with the help of streamer method,the flow field test and analysis were carried out via hot-wire anemometer.The results show that the annular shape of the backflow area will not be changed in the presnece of the pre-combustion chamber.By contrast,the recirculation zone,formed within the burned and featured by low axial velocity and high turbulence intensity,is beneficial to pulverized coal ignition. For the aera of X/D < 1. 3,the area of backflow area is prohibited due to the existence of pre-combustion chamber,which is conected to the squeezing effect of the conical pre-combustion chamber on the airflow. While for 1.32.3,the effect of pre-combustion chamber on the internal flow field can be ignored.The widest part of the recirculation zone is reduced from 0.97 D to 0.86 D under the action of the pre-combustion chamber.At the same time,the maximum relative recirculation rate is moved from the cross section X/D = 1 to 1. 6 and the relative recirculation rate is decreased from 1. 17 to 0. 99. The existence of pre-combustion chamber has a great influence on the axial mean velocity and turbulence distribution in the secondary air zone. Under the condition of no pre-combustion chamber,in the region of X/D<0.6,the peak values of velocity and turbulence appear; in the region of X/D>1.6,the peak values disappear,and the inner and outer secondary air are completely mixed; under the condition of pre-combustion chamber,in the region of X/D<0.6,the velocity increases along the radial direction,and the turbulence decreases along the radial direction; in the region of X/D>1.6,the velocity and turbulence are evenly distributed along the radial direction.The existence of pre-combustion chamber is beneficial to the stable combustion of pulverized coal in recirculation zone.It plays the role of rapid ignition of pulverized coal and stable combustion of low volatile coal in engineering application.In addition,the over-temperature or coking phenomenon of the pre-combustion chamber will be prevented by the pre-combustion chamber wall with large air velocity and strong rigidity,which is expected to prolong the trouble-free operation time and overall service life of the pulverized coal burner.