Performance Analysis And Working Characteristics Research Of A Novel Rotor For Gear Type Compressor

Gear type compressor is a novel rotary volume compressor,which has the advantages of simple structure,high reliability and simple processing.Based on the theory of plane engagement,the envelope equations of point,arc and circular involute used to construct the gear rotor are derived.Then two new gear rotors for gear type compressor,full mesh gear rotor and pin tooth arc gear rotor,are established.The parameter equations of each component profile are derived.The meshing relationship between the convex gear rotor and concave gear rotor is analyzed,and the performance of two new gear rotors is compared.For the pin tooth arc gear rotor,the influence of the number of convex teeth and the tooth height coefficient on the tooth shape is studied.The area utilization coefficient,relative clearance volume and internal volume ratio of the pin tooth arc gear rotor are calculated with the variation law of the number of convex teeth and the tooth height coefficient.A new discharge port is designed according to the profile of the pin tooth arc gear rotor of the pin tooth.The characteristics of the pressure increasing process of the gear type compressor are analyzed,and the variation law of the volume of the working chamber with the spindle angle is obtained.Three-dimensional numerical simulations of the working process of the gear type compressor with the pin tooth arc gear rotor are carried out,and the distribution of pressure fields,velocity fields and temperature fields are revealed,and the variation law of the pressure of the working chamber varying with the angle is obtained.The force and deformation of the pin tooth arc gear rotor are analyzed with ANSYS.The results show that the proposed full mesh gear rotor and pin tooth arc gear rotor have the advantages of less composition curve and less non smooth points.The proposed pin tooth arc gear rotor has the advantages of small relative clearance volume,large area utilization coefficient and large internal volume ratio.For the pin tooth arc gear rotor,with the increase of the number of convex teeth,the area utilization coefficient decreases while the relative clearance volume increases and the internal volume ratio decreases.When the tooth height coefficient increases,the area utilization coefficient increases while the relative clearance volume decreases first and then increases,and the internal volume ratio decreases.Through numerical simulations,it is found that the internal leakage of gas in compression results in a small pressure difference between the left and right working chambers,and the velocity vector at the meshing gap of rotors is the largest in the discharge process.The leakage of high pressure gas will cause the temperature to increase in the equal volume transport chamber,where the gas pressure fluctuates accordingly.The pressure returns to the normal value after the discharge port is closed.The stress analysis shows that the maximum deformation of the pin tooth arc gear rotor is at the top of the convex tooth and the maximum stress is located on the cycloid side of the tooth groove.The research contents of this paper are very important to guide the design of profile of gear type compressor,improve the working process and reveal the internal flow fields.