Nonlinear dynamics and vibration mechanisms in air scroll compressors: a study on orbiting and fixed scroll pair.

Scroll compressors exhibit significant potential for application. However, severe vibration issues substantially compromise their reliability. This study aims to unveil the nonlinear meshing vibration mechanisms of the orbiting and fixed scroll pair (OFSP) in air scroll compressor. A nonlinear dynamic model of the meshing vibration of OFSP incorporating radial clearance, time-varying meshing stiffness, friction, contact forces, and meshing errors is established. The meshing state and disengagement mechanism of OFSP are investigated based on phase trajectories and the time history of dynamic meshing force. The combined analysis using bifurcation diagrams and largest Lyapunov exponent (LLE) reveals the influence of the load factor and error fluctuation amplitude on the nonlinear dynamic behavior and stability of OFSP. Two distinct states are identified: complete engagement and engagement-disengagement. Key findings reveal that the dynamic meshing force demonstrates periodic variations across two distinct time scales, amplifying system complexity. The sudden change of the dynamic meshing force in the direction results in the two scrolls to disengage, deteriorating the dynamic performance. Crucially, lowering the load factor or increasing the meshing error amplitude induces a transition in OFSP from stable periodic motion to chaos through bifurcations, leading to greater disengagement severity. These insights provide critical guidance for optimizing air scroll compressor design to suppress vibration-induced failures.