The Numerical Simulation On Dynamic Characteristic Of Twin-wraps Scroll Compressor

Scroll compressor is a new type of positive-displacement compressor. Compared with other types of compressor, scroll compressor has many advantages such as simple structure, high-efficiency, low noise, low cost, smooth operation, etc. And widely used in refrigeration, air conditioning, a variety of gas compression, supercharged engine and other fields. As the market demand gradually to large displacement direction and development of high-power, it is praised by scholars from various countries through using twin-wraps structure, which can increase displacement, decrease the scroll dimensions and reduce dynamic and static relative sliding plate significant speed. This article is based on the twin-wraps scroll compressor with low pressure as the research object. On the basis of the scroll meshing theory, established the geometry model of the twin-wraps scroll compressor and dynamics model of the orbiting scroll with its gas loads and the ball-orbiting scroll system. And carry on the simulation calculation, providing a theoretical basis for the optimization design of the twin-wraps scroll compressor.Firstly, based on the Circle theory of involute, established the theory of cut-wrap at the starting of the warp through introduce two parameters which are the center plane angle at the beginning of the wrap-type and the center plane angle at the end of the wrap-type. Then the corresponding geometric theoretical model is built by considering the impact from the wall thickness on the exhaust chamber in center. Using the MATLAB software, simulates the variation of the compression chamber, the discharge chamber in center and the pressure with the crank angle, and the variation of the compression ratio and the volume ratio of the pressure chamber, the feature of the chamber’s working process, which from the formation of working chamber, compressed to exhaust are analyzed.Secondly, based on the theory of cutting the scroll tooth, the mathematical models of gas load about the twin-spirals scroll compressor are established, and the changes of the gas load in a crank rotation cycle are simulated. Through the analysis of the mathematical model parameterization, get the constraint range of geometric parameters like a, a and H, which due to the impact of gas load vortex, obtain linear relationship between the geometry parameters with the gas force. In the range of constraints, the gas force is more sensitive to changes of geometric parameters outside the range of constraints. With examples verify the accuracy of the calculation results. The results show that though optimization the stress characteristic of orbiting scroll is improved and scroll area is increased. Thus the performance of twin-spirals scroll compressor is enhanced.Finally, the ball anti-rotation mechanism is studied, and the ball-orbiting scroll mechanical model is built through by analyzing of the ball anti-rotation mechanism and the orbiting scroll, Using newton iterative method to numerical equations, and get the crank pin force changing with the spindle rotation. For further numerical simulation of the performance about the twin-wraps scroll compressor provide theoretical basis.