Investigation of Parameters Influencing the Establishment of Hydrostatic Mode in the Crosshead-Guide Assembly of High-Pressure Plunger Pump

Introduction . When applying hydraulic fracturing technology to increase the efficiency of formation fluids, high-pressure pumps with a crosshead drive assembly are used. The major problem in the operation of these pumps is the wear of the crosshead guides. The crosshead is a flat sliding friction pair, leading to wear of the plunger seals and a decrease in the basic pump performance indicators. To solve this problem, it was previously proposed to use new materials and antifriction coatings, original designs of friction units, etc. However, a detailed description and solution to the problem under consideration has not been found in the literature at present. The objective of this study is to determine, under maximum load, the influence of the unit design, process temperature and pressure in the lubrication system on the values of the parameters that provide for the hydrostatic mode for a flat thrust bearing in a crosshead-guide unit of a high-pressure plunger pump. Materials and Methods . The parameters were determined by the simulation technique using modal analysis applicable in the case of high dynamic loads acting on the studied unit. The calculation of the hydrodynamic parameters of the lubricating layer was based on the combination of the Reynolds model and the Stokes model in numerical modeling. The study was conducted using a calculation model representing a section of a plunger pump, considered as “flexible bodies” model, in the field of gravity forces. The mathematical dependences of the parameters under consideration were presented in the form of regression equations obtained from the results of a numerical experiment. Results . The maximum load on the lower crosshead guide was determined, for which further hydrodynamic studies were conducted. Factors influencing the process were studied — gaps filled with lubricant (depending on the design of the unit), temperature, and pressure in the lubrication system. Mathematical dependences of the influence of the considered factors on the values of the parameters determining the establishment of the hydrostatic mode were obtained. Discussion and Conclusion . The obtained mathematical models show the degree and influence of the factors under consideration on the studied parameters of the hydrostatic lubrication mode of the unit — the force acting on the crosshead from the lubricating layer, and the mass flow rate of the lubricant at the outlet of the system. It is found that the greatest influence is exerted by the change in the volume of gaps filled with lubricant, the mass flow rate of lubricant at the entrance to the system, which simulates the increase in pressure in the lubrication system of the friction unit. The results obtained do not contradict the conclusions reached in works on similar topics, and can be used in further research.