Using an all-speed algorithm to simulate unsteady flows through mixed hydro-pneumatic systems

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.In this paper, we take two important steps to analyse hydropneumatic systems and their components. In this regard, we first extend a new all-speed approach to solve the full onedimensional Navier-Stokes equations. The extended approach can be equally used to simulate both gas and liquid flows, considering an equivalent gas constant for the latter case. We further apply the extended approach to analyse both liquid water and air flows through two separate hydro-pneumatic circuits. To verify the accuracy of our solution, we compare our solutions with those of Lax-Wendroff method. The comparison shows that the current proposed all-speed algorithm provides solutions with excellent accuracy. One important advantage of this new extended algorithm is in treating the two-phase fluid flow problems, where there are mixed liquid water and vapour behaviours, e.g., diaphragm pumps. Therefore, as a second contribution, we simulate a multi-component diaphragm pump, whose parts consist of check valves, signal subsystems, conveys, and air distribution system. As a final step, we obtain the limit of cavitation temperature at the suction side of the check valve for a sample diaphragm pump.