Different structures for fatigue life analysis of plunger pair considering stress distribution

Harsh working conditions such as high dust, high humidity, and abrasive particle contamination exist underground in coal mines. In such environments, the plunger pair is vulnerable to impacts, and the problem of wear failure is prominent. Taking the RMI Trimax S500 plunger pump as the research object, a plunger with an alumina coating was selected, the type of coating material and spraying process parameters were clarified, and relevant mechanical calculation formulas were derived. Three-dimensional models corresponding to plunger pairs of different structures were established to simulate the stress distribution under typical pump unit operating pressure, and the fatigue life was theoretically calculated using the Archard wear formula. The results show that with the increase of plunger diameter, the stress distribution in the static analysis shows dispersed stress spots; in the dynamic analysis, the maximum stress of the plunger pair shows a continuous climbing trend, while the fatigue life shows a decreasing trend. Theoretical basis and engineering reference is provided to the selection of plunger pairs in high-water-based high-pressure emulsion pumps, and has important engineering significance for improving the overall reliability of the pump body and extending its service life.