Research On Rotor System Dynamic Properties Of DH Centrifugal Compressor

DH centrifugal compressor is a wide-applied centrifugal compressor type, while domestic DH centrifugal compressor has come to lots of difficulty in design aspect as well as application aspect. Take one Japanese DH centrifugal compressor as a sample, some three parallel axis gear-bearing-rotor system modes, dynamic properties of which are studied in the thesis, are set up. The research results of the thesis are helpful to design and application fields of domestic DH centrifugal compressor as well as further research on three parallel axis gear-bearing-rotor system including a shaft coupling and a electrical motor.The main work of the thesis can be included as follows: Firstly, based on basic knowledge of gear-bearing-rotor system dynamics, take a Japanese DH centrifugal compressor as a sample, some three parallel axis gear-bearing-rotor system finite element modes, dynamic properties of which are studied in the thesis, are set up. Secondly, dynamic characteristics of coupling three parallel axis gear-bearing-rotor system and dynamic properties of non-coupling shafts are compared. Thirdly, the influence of journal bearing damp to three parallel axis gear-bearing-rotor system dynamic properties is researched. Finally, the influence of bearing parameters and gear parameters to three parallel axis gear-bearing-rotor system dynamic properties is studied.The main research results can be summarized as follows. (1) The number of three parallel axis gear-bearing-rotor system's natural frequencies reduces while bearing clearance ratio and driving shaft bearing width-diameter ratio, which almost have no influence to system's low stage natural frequencies, increasing to some degree. Bearing clearance ratio and driving shaft bearing width-diameter ratio should be properly designed, which can make a three parallel axis gear-bearing-rotor system work steady. (2) The variation of lube oil temperature influences the three parallel axis gear-bearing-rotor system natural frequencies between 0Hz and 115Hz little. The numeric value of natural frequencies between 120Hz and 270Hz scales up while lube oil temperature increasing. (3) The stability of the system goes worse and the numeric value of natural frequencies decreases while rotational speed decreasing. (4) The three parallel axis gear-bearing-rotor system dynamic characteristics change little while skew gear spiral angle varies between 8 degree and 20 degree. (5) The low stage natural frequencies of skew gears driving system and the low stage natural frequencies of spur gears driving system are almost as the same when the engaged stiffness at the same order of magnitude. The number of spur gears driving three parallel axis gear-bearing-rotor system's natural frequencies reduces while the engaged stiffness increasing.