Analysis of Vertical Vibration Mechanism of Reciprocating Compressors considering Flexibility of Piston Rod and Crosshead Subsidence

This paper is targeted on the vertical vibration of the crosshead in a reciprocating compressor, taking into consideration the crosshead subsidence. The traditional model of the compressor is usually a crank-slider mechanism system without considering the abrasion loss for any parts, thus neglecting the influence of the piston rod flexibility. A rigid-flexible model of slider-crank is described theoretically, in which the crank, connecting rod, and crosshead are treated as rigid bodies, while the piston rod connected to the crosshead is considered as a flexible body. Lagrange equation was adopted to establish the kinetic equation of the system, considering the mass of the crank, the linkage, and the crosshead. After modeling the mechanism, the simulation shows that the dynamic response of the crosshead will be greatly influenced if crosshead subsidence is considered. Additionally, the influence of the crosshead subsidence is also investigated, and some new phenomena arise especially the vertical vibration of crosshead.