Numerical Analysis Of The Cooling Of Bladed Disk And The Abrasion Mechanismin Of Rotor Blade In The Flue Gas Turbine

The flue gas turbine is an important energy recovery equipment in petrochemical industry, which plays an important role in the catalytic cracking of heavy oil production process, has active significance to reduce power cost, saving energy, reducing harmful gas emissions. The working principle of the flue gas turbine is similar with steam turbine and gas turbine, It is the use of temperature up to900-1000K expansion produced by combustion of toxic and harmful gases (material) of heavy oil catalytic cracking process which drive axial flow compressor or generator.In order to ensure the key components, such as blade、wheel of sufficient strength and service life. In addition to the use of high temperature strength, good materials, it also need using low temperature steam to cool the high temperature components, for reducing the thermal stress and surface temperature of high temperature components to ensure the safe operation of the unit. After cooling work the cooling steam flow into the main channel, resulting a strong interference on the main flow of the flue gas, making the air flow in the cascade passage very complex. Working medium of flue gas turbine is a mixture of steam, nitrogen, carbon dioxide and other components, but also contains a lot of alumina and silica as the hard catalyst particles, cascade passage vortex flow, two times against repeated impact, solid particle erosion of blade, causing the blade root and flange damage, resulting in turbine blade change frequently, frequent accidents. However, the current research on the gas turbine has not yet attracted extensive attention, its design is always modeled the modular design of the steam turbine, without considering the complex flow of the gas-solid two-phase flow, cooling steam, two flow and so on, which is too ideal. Therefore, to study the flow field, temperature field gas-solid two-phase flow, blade wear problems of flue gas turbine, has the vital significance to improve the flue gas turbine design, improve the flue gas turbine service life, and ensure the safe operation of the unit.This paper using CFD technology, researches the flue gas turbine of a Sinopec Group with large commercial software CFX. First, using fluid-solid coupled heat transfer method to calculate the cooling effect of different flow of cooling steam for the moving impeller disk, get a roulette temperature field position, combined with business operation experience which shown that the current operating conditions of the cooling steam flow can satisfy the security needs, proposed to reduce the flow to0.28kg/s, in order to save the operating costs. Next simulate the inside flow field of the flue gas turbine in the condition of cooling steam and without cooling steam. The result shows that the cooling steam interference the main flow seriously, which causing the flow of outlet nozzle instability, especially has a strong vortex and secondary flow near the moving leaf root, which are consistent with the actual wear of the blade position. After that using the Lagrange method, select the particle trajectory model to simulate the flow behavior of the catalyst particles in the cascade flow channel, analysis the wear mechanism of rotor blades in each wear region. According to the calculation results of the flow field and gas-solid two-phase flow:cascade airflow adverse current situation is the root cause of blade wear. Therefore, this article will change the original radial cooling steam outlet to the axial outlet, simulate the flow field, temperature field, gas-solid two-phase flow to show that the export structure can meet the roulette cooling requirements and have a significant effect in improving the dynamic cascades flow situation, unit efficiency and reducing abrasion of the rotor blades.