Numerical simulation of gas leakage through stuffing box packing of reciprocating compressors

In this research, leaking flow from inside the cylinder-piston space to the crankcase through the very narrow passage in the stuffing box is numerically simulated. Two distinguish geometries are considered, and it is assumed the flow is steady, three-dimensional, non-isothermal, laminar, and compressible. The governing equations (including the mass, momentum, and energy conservations) are solved simultaneously along with the ideal equation of state by finite volume method. It is demonstrated that the Mach number is under ۰.۸ in the majority of the domain. Therefore, the pressure-based strategy is selected to have faster convergence. It is found that the maximum leakage rate for one-row and two-row packing is respectively ۴۹.۶ and ۴۱ g/s obtained for a pressure difference of ۷۰ bar. Also, it is shown that the presence of the second row is mandatory to be in safe condition. The percentage of leak control by the second row is much higher for lower pressure differences. Strictly speaking, the second row of rings decreases the leakage rate depending on the pressure difference from ۷.۹% to ۶۰.۷%. To the best of the authors' knowledge, this would be the first time the flow through the stuffing box is simulated.

Keywords:

Natural gas processing plants , Reciprocating compressor , Stuffing box , Numerical Simulation , Finite volume method