Benchmark Trials of Axial-Piston Pumps at Different Levels of Oil-with-Water Fouling

The results of trials of axial-piston pumps with watered lubrication are presented. It has been revealed that the wear intensity of pump pistons follows a logarithmic law in relation to the water content of oil, which (up to 3%) results in a four- to sevenfold gain of the dependent value, with the expectation of a subsequent increase. The interaction between the roughness parameter for the pistons surface and water content in oil demonstrates an exponential behavior and, supposedly, tends toward saturation at 3% water content. The increase in water content from 0 to 3% causes the piston surface roughness to increase owing to “catastrophic” wear out. The latter is indicated by the occurrence of plastic strain on contact surfaces.