Simulation of Pressure Distribution in Confusor and Diffuser Gaps

The paper presents problems related to the flow of selected liquids, such as water, aqueous emulsion and hydraulic oil, through confusor and diffuser gaps in the kinematic pair piston - cylinder in pumps and multi-piston motors. The values of the Reynolds number for those liquids were presented to indicate if the flow is laminar or turbulent. An analytic equation was developed on the basis of the Navier-Stokes equations and the continuity equation in order to obtain pressure in the gap. The results of the pressure distribution in the confusor and diffuser gaps are presented as dependent on liquid viscosity and on piston velocity in the cylinder, with the piston eccentricity taken into account.