Dynamic Flow Field Simulation Of The Sliding Vane Compressors With Rotating Cylinder

The sliding vane compressor is widely used in vaccum pumps,small air compresors and small air conditioning refrigeration equipment for its compact structure,low speed,stable operation and continuous working for a long time.However,the sliding vane compressor generally has relatively low pressure ratio,and large mechanical friction occured between the cylinder and the sliding vanes and the rotor,resulting in energy loss,which seriously affects its efficiency and service life.The synchronous rotary compressor solves the friction and wear problem by a moving cylinder that rotates synchronously with the rotor.However,since it has only one sliding plate and the arrangement of the inlet and outlet is complicated,greater pulsation flow but lower efficacy are resulted in.In this paper,a sliding vane compressor with a rotating cylinder was proposed and investigated to eliminate the friction and wear between the cylinder and the sliding vanes in reference to the synchronous rotary compressor.The main research contents and results of work are as follows:The theoretical relationship was deducted of the performances with the geometry and the structural design of the sliding vane compressor with synchronous rotating cylinder.A 3D CFD model was established based on the compressor geometry theory design;and the dynamic mesh technology was adopted with the UDF program to complete the simulation of the dynamic process.The friction loss of the rotating cylinder structure was estimated and compared with that of the conventional sliding vane compressor and confirmed that the rotating cylinder structure can greatly reduce the friction and abrasion between the cylinder and the sliding vanes.Five schemes with different central angle?_o and coverage angle??_o of the designed axial drop/circular outlet of#1:-28°/45°,#2:-28°/30°,#3:-28°/15°,#4:-23°/30°and#5:-18°/30°were designed for CFD simulation,and by analyzing the internal flow field,the effect of the exit configuration on the parameters of pressure,temperature and mass flow rate as well as the compression performance of each scheme was presented.The results show that:The outlet coverage angle and position have great impact on the exhaust process and state of compression at a given pressure ratio.Proper outlet coverage angle??_o can slow the vortex at the outlet,and smooth the exhaust process.Moving properly the outlet position?_o towards the contact line of the cylinder and the rotor can increase the internal pressure in the chamber near the exit,and thus raise the potential pressure ratio with reduced mass flow rate.The effect of the number of sliding vanes on the compression performance was studied,and three schemes with 2,4 and 8 sliding vanes were simulated.The internal flow field and leakage pattern of each compressor scheme were also quantitatively compared and analyzed in terms of the outlet mass flow rate,pressure distribution and flow-pressure ratio characteristic curves.The results show that reducing the number of sliding vanes can not only greatly increase the theoretical design pressure ratio of the compressor,but also increase correspondingly the leakage and pasation magnitude;the scheme with 4 sliding vanes has the optimal compression performances that a mild pulsation magnitude of the outlet mass flow rate,a broadened pressure ratio with restricted internal leakage.