Development of a transient gas dynamic model for the simulation of pulsation in reciprocating compressor piping systems

Abstract

The subject of this paper is to develop a nonlinear transient dynamic model for simulating the pressure pulsation in reciprocating compressor piping systems. The model allows the interaction between the piping response and compressor processes. The two-step Lax–Wendroff method is employed to obtain solutions to the unsteady flow equations at internal points in a pipe, and the Trapezoidal version of the method of characteristics is adopted for handling boundary conditions. The compressor, which serves as a boundary condition for predicting the piping's pressure pulsation, is modeled comprehensively on the basis of the first law of thermodynamics, the valve dynamics assumed as a one-degree-of-freedom system and the flow through valve by introducing an effective area for flow through the valve throat. It is worth to note that, to solve the compressor boundary condition, all the related equations are necessary to be solved simultaneously to obtain the pulsating pressure in the pipe end, pressure variation in the cylinder, valve response, mass flow rate, indicated power, and other compressor performance parameters. Numerical results based on these proposed modeling techniques show a good agreement with previous measured data.