Dynamic analysis of reciprocating compressor with clearance and subsidence

In this paper, the reciprocating compressor with clearance and subsidence of the crosshead is studied, considering the varying cylinder pressure. To investigate the nonlinear dynamical behaviors of the reciprocating compressor precisely, a novel dynamic model of the reciprocating compressor of single cylinder with clearance and subsidence for the varying cylinder pressure is established based on the Lagrangian approach. It is demonstrated that different clearance sizes, subsidence sizes and crankshaft angular velocities can affect the dynamic response of the crosshead in the horizontal direction, respectively. The analysis results of dynamic response illustrate that with the increase of clearance sizes and subsidence sizes, the influence of crosshead displacement, velocity and acceleration increase, but the effect of clearance is much stronger than subsidence. Fast Fourier transformation is also applied to analyze the frequency spectrum of the system response. Moreover, the stability of the motion is studied using phase trajectories, maximum Lyapunov exponents and Poincare sections. Numerical solution results show that clearance sizes, subsidence sizes and crankshaft angular velocities change the dynamical behavior of the system. Through calculation of the maximum Lyapunov exponents and Poincare portraits, the results reveal that the reciprocating compressor system is characterized by chaotic behavior with the faults of clearance and subsidence. Furthermore, with the increase of the clearance sizes and the crankshaft angular velocities, the shapes of chaotic phase trajectories have changed greatly, and varied inconspicuously with the increase of subsidence sizes in reciprocating compressor system.