The influence of water and mineral oil on mechanical losses in the displacement pump for offshore and marine applications

In this paper mechanical losses in a positive displacement pump supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted by using a prototype satellite pump of a special design. The design of the satellite pump is presented in the article. The pump features and a non-circular tooth working mechanism was developed to work with both water and mineral oil. The sources of mechanical losses in such pump are also characterized in this paper. On this basis, a mathematical model of the losses has been developed and presented. The results of the calculation of mechanical losses according to the model are compared with the results of the experiment. The experimental studies have shown that the mechanical losses in the water pump are even 2.8 times greater than those in the oil pump. It has been demonstrated that the mathematical model well describes the mechanical losses both in the water pump and the oil pump. It has been found that the results from the loaded pump simulation (at Δp=25MPa) differ from the results of the experiment by no more than 5% both for oil and water.