Casing Stability Enhancement Design And Numerical Research Of An Axial Gas Turbine

As the core components of gas turbine, the axial compressor has been developed a lot recently with the development of science and technology. Gas turbine usually works under off design conditions, once its working state deviating from the design point to a certain extent,compressor turn into unstable working condition, its performance decline seriously accompanied by fiercely vibration, lots of noise, even appearance of mechanical failure leading to machine damage. Casing treatment is a method which enlarges compressor stable operation scope, and it has been applied extensively in engineering. This paper deals with stall margin extension mechanism research and casing stability enhancement design for an axial compressor. Its main work is as follows:1. Validation of the calculation model. This paper deals with an axial compressor and grid independence study is conducted. Compared with the designed and experimental values,an optimal calculation model is obtained.2. Casing treatment feasibility study. Casing treatment takes an apparent effect on compressor with blade tip stall. So compressor flow field characteristics should be researched and the types of the rotating stall on the compressor should be judged.3. Design of circumferential grooves and its stall margin extension mechanism study.Firstly,the stall margin extension mechanism of circumferential grooves is revealed through numerical flow field research on a common one and then research of different cross section and different processing grooves position impacts on stall margin extension effect is conducted in circumferential grooves casing treatment design.4. Design of self-recirculation casing treatment and its stall margin extension mechanism study. Stall margin extension mechanism of self-recirculation casing treatment is investigated based on flow field research on a self-designed one. And then how structure of injection nozzle, structure of extraction hole and different injection nozzle position affect self-recirculation casing treatment’s stall margin extension effect is studied in self-recirculation casing treatment design.