The Numerical Optimization Of The Stators In Centrifugal Compressor Model Stage With Small Flow Coefficient

Centrifugal compressor model stages with small flow coefficient are often characterized by small height of blade and limited outlet width. The friction loss, leakage loss, and secondary flow losses are much higher comparing to conventional model stages. As a result, the efficiencies of such model stages are usually not very high. With the development of CFD tech, foreign manufacturing factories in the world had made great progress in improving the compressor efficiency. In China, however, only a few primary works had been reported.The model stage studied in this thesis was designed by Nuovo Pignone in the 70s last century but is still in use in manufacturing factory in China. The efficiency of such a model stage is usually 10% lower than the modern state-of-art products in current market. Significant improvement had been reported in reference [1] following many numerical experiments and a series of structure modifications. However, it wasn't validated in experiments.As the models used in reference [1] was different from the real experimental model, a new numerical CFD analytic platform based on experimental model was developed in this thesis, using the same approach as that used in reference [1]. Intensive numerical experiments were carried out to explore the optimal geometry of the diffuser, curved duct and return channel. And an increased of efficiency by 7% was achieved. Off-design predictions indicate an improved off-design performance than that of the design reported in reference [1].