Numerical Simulation Of Erosion Wear On The Rotors Of Flue Gas Turbine

Flue gas turbine is the most critical equipment in FCC energy recovery devices which was widely used in the petrochemical industry. Shaft power was output to turbines or compressors by high-temperature gas expanding power drives dynamic blade of flue gas turbine rotating rapidly, and creates great fortunes. The serious erosion wear caused by catalyst particles impacting blades of high-speed gas not only reduces the strength of rotors,but changes the flow channel, deteriorates the flow conditions, decreases the efficiency, even causes shut down accidents. So it’s significant to study erosion wear of flue gas turbine rotors for the stable operation of the FCC energy recovery devices.The rotors material model of erosion wear for high-temperature was established based on micro-cutting and deformation fatigue wear. The volume loss of material from micro-cutting was calculated by integration, and the erosion rate of GH864 at different angles was calculated and compared with other experimental data according to the deformation wear expressed by localization model and low-cycle fatigue. The erosion properties and rates was researched combine with high-temperature characteristic of GH864 under the actual conditions The results showed that GH864 presented the erosion properties of plastic metal,and the angle was 50° not 30°when maximum erosion rate occurs. The critical deformation of GH864 decreases firstly with the increasing of the temperature, then increases slightly, the maximum deformation increases and the impact number grows exponentially. The erosion rate increases with the increasing of temperature at 30° and 50°, and slows down after 550℃.The erosion rate barely changes between and 400℃ at 90°, then decreases rapidly after 400℃.The variations of flow stress, dynamic hardness and critical strains have great influence on erosion characteristics in different temperatures, but reduce deformation wear also.The key factors such as pressure, velocity, velocity vector and the angle on rotor blade which have significant influence on the flow of catalyst particles and erosion were studied by numerical simulation. The results showed that the pressure drop occurred in the rotor-stator flow, especially the low pressure area at the rotor outlet caused instability of gas flow. There is a large temperature difference on rotor blade, the pressure surface temperature is between 77 K and 893 K, and the suction temperature is between 690 K and 880 K. The maximum velocity is400m/s at the leading edge of rotors, and accelerates from the back to inlet with the spout speed of 289 m/s to 336m/s. The impact angles between velocity vector and the pressure surface are high mostly, and low at the trailing edge; the pressure gradient of rotor in the radial direction is large. The secondary flow formed and the flow downward trend occurred,this affect the movement of particles.On this foundation, the flow laws of catalyst particles with different sizes, erosion areas and erosion rates of rotors were analyzed by DPM, the methods and measures to prevent and reduce the erosion of rotors were explored. The flow laws of catalyst particles change with size, the size smaller, the distribution in runner more uniform; otherwise the size bigger, the more likely to concentrate on the top of rotor where erosion increase. The erosions of small particles are mainly on the leading and trailing edges; the erosions of big particles are mainly at above middle of rotors. The total erosion increases firstly to 10μm, and then decreases with increasing of the size.