Study On The Stability Prediction And Optimization Of Centrifugal Compressor

The stability of centrifugal compressor operation has been the important bottleneck of the centrifugal compressor which has been developed to a high-level. Seals are important components in centrifugal compressor. Many accidents took place because of flow self-vibration produced in seals. So studying the instability mechanism of the centrifugal compressor non-contact seal, exploring various seal’s contribution to the stability of the rotor and finding a quantitative calculation method of the seal effect on the rotor instability is of great significance. It helps to design good sealing parts with large damping and low cross stiffness. The main contributions of dissertation are summarized as follows:1) Developed procedure of modeling a variety eccentric sealing model, improved the efficiency of the pre-treatment of CFD and realized parametric modeling of seal models. This program can get high quality meshes in a short period of time.2) This paper study the rotordynamic coefficients of three kinds of balance drum seal and calculate the Log.Decrement under a nine-stage compressor rotor. Compare the result the of labyrinth seal, honeycomb seal, hole-pattern seal and dig the effective of seals about the rotor stability.Deep study the relative between detail structure of hole-pattern and compressor leakage quantity or the influence of the Log.Decrement. Analysis the key factors affecting the performance of hole-pattern seal.3) Study kinds of centrifugal compressor impeller eye seal, calculate the rotordynamic coefficients under different boundary conditions and discuss the results. Put forward a method of calculate the sensitivity of different conditions on the Log.Decrement of the rotor with seal.4) Modeling the whole model stage of centrifugal compressor with inter-stage seal, impeller eye seal and study the flow law in the single stage and validation the method of evaluating impact on the stability of the rotor of single stage flow.The work of this paper which is to predict the stability of rotor system, and puts forward the methods to solve the problem of stability is of great significance, and helps to design good sealing element with features of large damping and low cross stiffness.