Performance Analysis Of Complicated Working Conditions And Unsteady Numerical Study Of Flue Gas Turbine

The energy problem has become an outstanding problem which hinders the national economy from developing fast and healthily. Due to the energy shortage of petroleum and natural gas and the low energy utilization efficiency of existing equipments, our national economy grows with low quality and the ecological environment is destroyed seriously day by day. To solve our country's energy and environment problem fundamentally, hugeness scientific workers must endeavor to develop new energy saving technologies and improve the existing equipments'energy utilization efficiency.The flue gas turbine is one kind of active turbomachine. As the key equipment in petrochemical enterprise, it is widely used in petroleum chemical industry. The flue gas turbine produces work by using high temperature flue gas from the technological process of catalytic cracking reaction. This helps sufficient use of energy and emission reduction. Hence it plays a very important role in energy saving and environmental protection. Its running situations impact directly on the equipments'long-term and safe operation and the enterprises'economic benefits. However, a flue gas turbine generally works in bad conditions such as high temperature, high pressure and impact of solid particles. These bad working conditions make the efficiency low, running period short and damage of blade serious. So the flue gas turbine became one of equipments with the highest failure rate in petrochemical enterprises.This paper combined with the scientific research project of optimization analysis and design of the flue gas turbine of the triad unit of Shandong Jingbo Petrochemical Co, Ltd. Firstly, the preliminary numerical simulation of the internal flow in the flue gas turbine was conducted using the commercial CFD software-NUMECA. And the results showed that some bad flow phenomena exited in the turbine. Through study and analysis, it is recommended that the moving blade installation angle of the turbine should be adjusted. And researches about influence of moving blade installation angle on the turbine's performance were carried out subsequently. Secondly, considering that the working condition of the flue gas turbine often changes in the enterprise production processes, numerical simulations of the flue gas turbine under variable conditions were conducted by means of changing the flue gas flow rate. Then the regularity of influence of flue gas flow rate on the turbine's performance was grasped and the performance curve of the flue gas turbine under variable conditions was drawn. As a result, a kind of superior running condition was recommended to keep the turbine working long and safely. Finally, in order to reflect the flow status in the flue gas turbine comprehensively and truly, unsteady numerical simulations of the internal flow under recommended condition were conducted using Nonlinear Harmonic Method which only exists in the NUMECA software. And the influence of stator-rotor interactions on the internal flow in the flue gas turbine was studied mainly. Basing on this study, the influence of the axial spacing of stator and rotor cascades on the turbine's performance was studied subsequently. And the optimal axial spacing of stator and rotor cascades was recommended in the last.Through above studies, some beneficial conclusions about structure improvement and running condition optimization of the flue gas turbine were obtained in this paper. These conclusions can provide some theoretical evidences and guidance which not only make the flue gas turbine run safely and stably but also improve enterprise's economic benefit.