Numerical Determination of Volumetric Effi ciency of High-Pressure Reciprocating Pumps

Results of experimental determination of variable-discharge high-pressure reciprocating pump performances [3, 4] show that by increasing the pressure on the pressure side of a reciprocating pump, at a constant stroke length, the discharge and volumetric effi ciency of the pump decrease. Mathematical expressions defi ning the theoretical and the actual pump discharge have been derived on the basis of the analysis of kinematic and hydrodynamic performances of a high-pressure, single-piston single-acting pump. The applied measuring system is described and examples of analysed measurement results are given. The Fourier approximation method is used to describe mathematically the experimental diagram of operating pressure p1=f(t). Assuming that physical properties of the fl uid are constant, and that geometric and kinematic characteristics of a pump have not changed, the value of volumetric effi ciency is defi ned as a function of pressure. Results of volumetric effi ciency calculation are given for a series of individually performed measurements in the range from H4T25 to H4T250. Results of the numerical determination of volumetric effi ciency confi rm that the chosen method is acceptable since calculation results differ from experimentally determined values by less than 1%