Computer Simulation of a Variable Fill Hydraulic Dynamometer; Part 1: Torque Absorption Theory and the Influence of Working Compartment Geometry on Performance

Abstract

A mathematical model of the steady state torque absorption process in variable fill hydraulic dynamometers is described. This is the initial part of a general model that has been developed to simulate the dynamic behaviour of Froude-type dynamometers under open-loop control and of an engine/dynamometer system under various closed-loop control modes. In this paper, the equations for steady state torque, energy dissipation, fluid vortex pressure in the working compartment and water outflow from the dynamometer are presented. Predictions by the model for the special case of characteristic running full torque absorption performance are compared with experimental test bed results for different working compartment geometries. Effects of vane angle and working fluid properties on maximum torque capability are examined. Subsequent parts of this paper will address the dynamic variable fill simulation.