A Generalized Approach to the Analysis of Feed Unevenness in Displacement Pumps

A generalized approach to the analysis of feed unevenness in positive displacement pumps is considered. A procedure for calculating the working processes in chambers of constant or variable volume in a discharge line as well as a nonstationary one-dimensional gas flow in a discharge pipe is developed. Boundary conditions are defined. Nonstationary one-dimensional flow is calculated by the method of “characteristics.” By means of a numerical experiment, variations in the pressure in the working chambers and along the length of the pipe as a function of the turning angle of the shaft are established. On the basis of pressure fluctuation in a discharge pipe, it is proved that the feed unevenness significantly exceeds the magnitude of the feed unevenness determined when the pressure fluctuation is not taken into account.