The Flow Field Analysis And Performance Research On Vehicle Twin-Screw Compressor

Abstract:Vehicle twin-screw air compressor is a volumetric gas compression machinery providing pneumatic conveying for bulk cement truck, the gas in the compressor internal is three-dimensional viscous compressible flow,the rotor is a core component of twin-screw compressor and is at work in complex stress, and rotor failure accounts for70%of the compressor fault. In order to reduce the failure rate and improve the operation efficiency of the compressor, the method of combining numerical simulation with experiment was adopted to carry on a three-dimension numerical simulation of the internal flow in the compressor and study the factors which influence the exhaust performance of compressor. Based on this, the fluid-solid coupling method was used to evaluate the strength of rotor. The main works is listed below:1. The mathematical model of internal flow field of compressor is established, the compressor internal flow field was numerically simulated by using CFD simulation software FLUENT, and the internal air pressure field, velocity field and temperature field have been gotten. The change of pressure, velocity, and temperature of the internal flow in the compressor was revealed, and the characteristic of the internal leakage and the flow loss was captured.2. Through analyzing them, the influence of the rotation speed and pressure ratio of compressor on outlet pressure and outlet temperature and internal flow condition was obtained; the influence of different rotor meshing clearance on the compressor outlet pressure, outlet temperature and the internal flow condition was obtained.3. The mechanical behavior of compressor rotor under various loading conditions was analyzed by finite element analysis. Based on considering the aerodynamic load and centrifugal load, the fluid-solid coupling analysis for rotor was conducted, and the effect of flow field on the rotor strength properties was revealed. By comprehensive considering of the rotor deformation and the exhaust performance of compressor with different rotor meshing clearance, the optimal rotor meshing clearance value was confirmed to be0.15mm when the compressor is at work.4. The effects of the rotation speed and pressure ratio of compressor on outlet pressure, outlet temperature were studied by experimental study, which verified the correctness of the simulation results. The certain guiding significance for optimization of operational parameters of twin-screw compressor was obtained by this research result, which can improve the operation efficiency of the compressor and reduce the failure rate.