Study of crosshead-guided lubrication systems for hydraulic fracturing plunger pumps

Abstract

Efficient extraction of hard-to-recover hydrocarbon reserves requires impressive expenditures on the use of advanced technologies and energy-intensive equipment. Hydraulic fracturing technologies require the use of high-pressure pumps (105 and 138 MPa), and this determines the use of plunger pumps in these conditions. To relieve the radial load on the plunger seals, a crosshead layout of the drive part is used. The goal is to investigate crosshead (guide) load distribution throughout the crankcase and also the oil distribution in the crosshead-guide gap to find the most efficient design. The methods of simulation modeling of the kinematics of the crosshead and connecting rod group with the use of modal analysis were applied for the study. The analysis was performed taking into account the elastic properties of the crosshead, seal and connecting rod. The Reynolds-Stokes-Halerkin finite element method (R-SGFEM) with sliding boundary conditions was used to model and study hydrodynamic lubrication. A study was conducted for three types of oil channels on the crosshead: one longitudinal channel at the apex, one longitudinal channel and two transverse channels, one longitudinal channel and three transverse channels. Load distribution graphs were obtained for the contact area with respect to the oil-feeding hole in the guide. The obtained data make it possible to understand the nature of the crosshead sliding on the guide and evaluate the possibility of providing the hydrostatic mode in the friction knot at different types of the lubricant supply into the contact zone. The study showed one of the causes of increased wear of the bottom guide of the crosshead, which consists in insufficient non-drying ability of the lubricating layer and allowed to determine the parameters for further research and optimization of the node design.